51
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Kim J, Kudisch M, Mudumba S, Asada H, Aya-Shibuya E, Bhisitkul RB, Desai TA. Biocompatibility and Pharmacokinetic Analysis of an Intracameral Polycaprolactone Drug Delivery Implant for Glaucoma. Invest Ophthalmol Vis Sci 2017; 57:4341-6. [PMID: 27556217 PMCID: PMC5015984 DOI: 10.1167/iovs.16-19585] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose We developed polycaprolactone (PCL) implants that achieve zero-order release of a proprietary ocular hypotensive agent (DE-117) over 6 months. Methods The release rates of DE-117–loaded PCL devices were tuned based on an established predictive model and confirmed by in vitro release studies. Devices containing DE-117 and empty devices were implanted intracamerally in normotensive rabbits for up to 8 weeks' duration. Devices were retrieved after rabbits were euthanized and evaluated for tissue adherence. The drug remaining in each device was analyzed by high performance liquid chromatography. Drug distribution in ocular tissues was measured by liquid chromatography coupled with a tandem mass spectrometry (LC/MS/MS). Results In vitro release of DE-117 showed zero-order release with a release rate of 0.5 μg/day over 6 months. Implantation in rabbit eyes demonstrated that the devices were well tolerated in the intracameral space. Quantification of DE-117 and hDE-117 (the hydrolyzed active form of DE-117) in ocular tissues (cornea, iris-ciliary body, aqueous humor, and vitreous humor) indicated sustained release of DE-117 and its conversion to hDE-117 when released from the device. Analysis of drug remaining in the device found that concentration of hDE-117 was below the limit of detection, indicating the encapsulated drug was protected from hydrolysis in the device. Conclusions Proof-of-concept PCL drug delivery devices containing DE-117 show promise as a long-term glaucoma treatment based on their zero-order drug release profile in vitro, biocompatibility in vivo, and effective distribution of released drug in relevant ocular tissues.
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Affiliation(s)
- Jean Kim
- UCB-UCSF Graduate Program in Bioengineering, San Francisco, California, United States
| | - Max Kudisch
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Sri Mudumba
- Santen, Inc., Emeryville, California, United States
| | - Hiroyuki Asada
- Santen Pharmaceutical Co., Ltd., Nara RD Center, Nara, Japan
| | - Eri Aya-Shibuya
- Santen Pharmaceutical Co., Ltd., Nara RD Center, Nara, Japan
| | - Robert B Bhisitkul
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States
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52
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Song S, Yeung R, Park J, Posselt AM, Desai TA, Tang Q, Roy S. Glucose-Stimulated Insulin Response of Silicon Nanopore-Immunoprotected Islets under Convective Transport. ACS Biomater Sci Eng 2017; 3:1051-1061. [PMID: 29250596 DOI: 10.1021/acsbiomaterials.6b00814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Major clinical challenges associated with islet transplantation for type 1 diabetes include shortage of donor organs, poor engraftment due to ischemia, and need for immunosuppressive medications. Semipermeable membrane capsules can immunoprotect transplanted islets by blocking passage of the host's immune components while providing exchange of glucose, insulin, and other small molecules. However, capsules-based diffusive transport often exacerbates ischemic injury to islets by reducing the rate of oxygen and nutrient transport. We previously reported the efficacy of a newly developed semipermeable ultrafiltration membrane, the silicon nanopore membrane (SNM) under convective-driven transport, in limiting the passage of pro-inflammatory cytokines while overcoming the mass transfer limitations associated with diffusion through nanometer-scale pores. In this study, we report that SNM-encapsulated mouse islets perfused in culture solution under convection outperformed those under diffusive conditions in terms of magnitude (1.49-fold increase in stimulation index and 3.86-fold decrease in shutdown index) and rate of insulin secretion (1.19-fold increase and 6.45-fold decrease during high and low glucose challenges), respectively. Moreover, SNM-encapsulated mouse islets under convection demonstrated rapid glucose-insulin sensing within a physiologically relevant time-scale while retaining healthy islet viability even under cytokine exposure. We conclude that encapsulation of islets with SNM under convection improves islet in vitro functionality. This approach may provide a novel strategy for islet transplantation in the clinical setting.
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Affiliation(s)
- Shang Song
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158, United States
| | - Raymond Yeung
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158, United States
| | - Jaehyun Park
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158, United States
| | - Andrew M Posselt
- Department of Surgery, University of California-San Francisco, San Francisco, California 94143, United States
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158, United States
| | - Qizhi Tang
- Department of Surgery, University of California-San Francisco, San Francisco, California 94143, United States
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158, United States
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53
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Stewart T, Koval WT, Molina SA, Bock SM, Lillard JW, Ross RF, Desai TA, Koval M. Calibrated flux measurements reveal a nanostructure-stimulated transcytotic pathway. Exp Cell Res 2017; 355:153-161. [PMID: 28390677 DOI: 10.1016/j.yexcr.2017.03.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 01/08/2023]
Abstract
Transport of therapeutic agents across epithelial barriers is an important element in drug delivery. Transepithelial flux is widely used as a measure of transit across an epithelium, however it is most typically employed as a relative as opposed to absolute measure of molecular movement. Here, we have used the calcium switch approach to measure the maximum rate of paracellular flux through unencumbered intercellular junctions as a method to calibrate the flux rates for a series of tracers ranging in 0.6-900kDa in size across barriers composed of human colon epithelial (Caco-2) cells. We then examined the effects of nanostructured films (NSFs) on transepithelial transport. Two different NSF patterns were used, Defined Nanostructure (DN) 2 imprinted on polypropylene (PP) and DN3 imprinted on polyether ether ketone (PEEK). NSFs made direct contact with cells and decreased their barrier function, as measured by transepithelial resistance (TER), however cell viability was not affected. When NSF-induced transepithelial transport of Fab fragment (55kDa) and IgG (160kDa) was measured, it was unexpectedly found to be significantly greater than the maximum paracellular rate as predicted using cells cultured in low calcium. These data suggested that NSFs stimulate an active transport pathway, most likely transcytosis, in addition to increasing paracellular flux. Transport of IgG via transcytosis was confirmed by immunofluorescence confocal microscopy, since NSFs induced a significant level of IgG endocytosis by Caco-2 cells. Thus, NSF-induced IgG flux was attributable to both transcytosis and the paracellular route. These data provide the first demonstration that transcytosis can be stimulated by NSFs and that this was concurrent with increased paracellular permeability. Moreover, NSFs with distinct architecture paired with specific substrates have the potential to provide an effective means to regulate transepithelial transport in order to optimize drug delivery.
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Affiliation(s)
- Tarianna Stewart
- Morehouse School of Medicine, Atlanta, GA, United States; Division of Pulmonary Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, United States
| | - William T Koval
- Division of Pulmonary Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, United States
| | - Samuel A Molina
- Division of Pulmonary Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, United States
| | | | | | | | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, United States
| | - Michael Koval
- Division of Pulmonary Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, United States; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States.
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54
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Weber RJ, Desai TA, Gartner ZJ. Non-autonomous cell proliferation in the mammary gland and cancer. Curr Opin Cell Biol 2017; 45:55-61. [PMID: 28314237 PMCID: PMC8811621 DOI: 10.1016/j.ceb.2017.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/27/2017] [Accepted: 02/08/2017] [Indexed: 12/28/2022]
Abstract
Cells decide whether to grow and divide by integrating internal and external signals. Non-autonomous cell growth and proliferation occurs when microenvironmental signals from neighboring cells, both physical and secreted, license this decision. Understanding these processes is vital to developing an accurate framework for cell-cell interactions and cellular decision-making, and is useful for advancing new therapeutic strategies to prevent dysregulated growth. Here, we review some recent examples of non-autonomous cell growth in the mammary gland and tumor cell proliferation.
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Affiliation(s)
- Robert J Weber
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States; Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, 600 16th Street, Room 522, San Francisco, California 94158, United States; Medical Scientist Training Program, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, United States
| | - Tejal A Desai
- UC Berkeley-UCSF Group in Bioengineering, 1700 Fourth Street, Room 216, San Francisco, California 94158, United States; UCSF Bioengineering and Therapeutic Sciences, 1700 Fourth Street, Room 216B, San Francisco, California 94158, United States
| | - Zev J Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States; UC Berkeley-UCSF Group in Bioengineering, 1700 Fourth Street, Room 216, San Francisco, California 94158, United States; Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, 600 16th Street, Room 522, San Francisco, California 94158, United States.
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55
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Fox CB, Nemeth CL, Chevalier RW, Cantlon J, Bogdanoff DB, Hsiao JC, Desai TA. Picoliter-volume inkjet printing into planar microdevice reservoirs for low-waste, high-capacity drug loading. Bioeng Transl Med 2017; 2:9-16. [PMID: 28503662 PMCID: PMC5426811 DOI: 10.1002/btm2.10053] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Oral delivery of therapeutics is the preferred route for systemic drug administration due to ease of access and improved patient compliance. However, many therapeutics suffer from low oral bioavailability due to low pH and enzymatic conditions, poor cellular permeability, and low residence time. Microfabrication techniques have been used to create planar, asymmetric microdevices for oral drug delivery to address these limitations. The geometry of these microdevices facilitates prolonged drug exposure with unidirectional release of drug toward gastrointestinal epithelium. While these devices have significantly enhanced drug permeability in vitro and in vivo, loading drug into the micron-scale reservoirs of the devices in a low-waste, high-capacity manner remains challenging. Here, we use picoliter-volume inkjet printing to load topotecan and insulin into planar microdevices efficiently. Following a simple surface functionalization step, drug solution can be spotted into the microdevice reservoir. We show that relatively high capacities of both topotecan and insulin can be loaded into microdevices in a rapid, automated process with little to no drug waste.
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Affiliation(s)
- Cade B Fox
- Dept. of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158
| | - Cameron L Nemeth
- UC Berkeley and UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158
| | - Rachel W Chevalier
- Dept. of Pediatrics, Division of Pediatric Gastroenterology, School of Medicine, University of California, San Francisco, CA 94158
| | | | - Derek B Bogdanoff
- Center for Advanced Technology, University of California, San Francisco, CA, 94158
| | - Jeff C Hsiao
- Dept. of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158
| | - Tejal A Desai
- Dept. of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158.,UC Berkeley and UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158
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56
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Affiliation(s)
- Ketul C. Popat
- Department of Bioengineering, University of Illinois at Chicago
| | | | - Tejal A. Desai
- Department of Bioengineering, University of Illinois at Chicago
- Department of Biomedical Engineering, Boston University
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57
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Weber RJ, Cerchiari AE, Delannoy LS, Garbe JC, LaBarge MA, Desai TA, Gartner ZJ. Rapid Organoid Reconstitution by Chemical Micromolding. ACS Biomater Sci Eng 2016; 2:1851-1855. [DOI: 10.1021/acsbiomaterials.6b00421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Robert J. Weber
- Department
of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States,
- Chemistry
and Chemical Biology Graduate Program, University of California, San Francisco, 600 16th Street, Room 522, San Francisco, California 94158, United States,
- Medical
Scientist Training Program, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, United States
| | - Alec E. Cerchiari
- Department
of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States,
- UC Berkeley−UCSF Group in Bioengineering, 1700 Fourth Street, Room 216, San Francisco, California 94158, United States,
- UCSF Bioengineering and Therapeutic Sciences, 1700 Fourth Street, Room 216B, San Francisco, California 94158, United States
| | - Lucas S. Delannoy
- Laboratory
of Stem Cell Bioengineering, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Station
15, Building Al 1106, CH-1015 Lausanne, Switzerland
| | - James C. Garbe
- Department
of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States,
- Life
Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Mark A. LaBarge
- Life
Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Tejal A. Desai
- UC Berkeley−UCSF Group in Bioengineering, 1700 Fourth Street, Room 216, San Francisco, California 94158, United States,
- UCSF Bioengineering and Therapeutic Sciences, 1700 Fourth Street, Room 216B, San Francisco, California 94158, United States
| | - Zev J. Gartner
- Department
of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, San Francisco, California 94158, United States,
- Chemistry
and Chemical Biology Graduate Program, University of California, San Francisco, 600 16th Street, Room 522, San Francisco, California 94158, United States,
- UC Berkeley−UCSF Group in Bioengineering, 1700 Fourth Street, Room 216, San Francisco, California 94158, United States,
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58
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Affiliation(s)
| | - Tejal A. Desai
- Therapeutic Microtechnology Laboratory, Department of Biomedical Engineering, Boston University, Boston, MA
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59
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Lance KD, Chatterjee A, Wu B, Mottola G, Nuhn H, Lee PP, Sansbury BE, Spite M, Desai TA, Conte MS. Unidirectional and sustained delivery of the proresolving lipid mediator resolvin D1 from a biodegradable thin film device. J Biomed Mater Res A 2016; 105:31-41. [PMID: 27508346 DOI: 10.1002/jbm.a.35861] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/24/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
Resolvin D1 (RvD1) belongs to a family of endogenously derived proresolving lipid mediators that have been shown to attenuate inflammation, activate proresolution signaling, and promote homeostasis and recovery from tissue injury. In this study we present a poly(lactic-co-glycolic acid) (PLGA) based thin-film device composed of layers of varying ratios of lactic and glycolic acid that elutes RvD1 unidirectionally to target tissues. The device demonstrated sustained release in vitro for 56 days with an initial burst of release over 14 days. The asymmetric design of the device released 98% of RvD1 through the layer with the lowest molar ratio of lactic acid to glycolic acid, and the remainder through the opposite side. We validated structural integrity of RvD1 released from the device by mass spectrometry and investigated its bioactivity on human vascular endothelial (EC) and smooth muscle cells (VSMC). RvD1 released from the device attenuated VSMC migration, proliferation, and TNF-α induced NF-κB activation, without evidence of cytotoxicity. Delivery of RvD1 to blood vessels was demonstrated ex vivo in a flow chamber system using perfused rabbit aortas and in vivo in a rat carotid artery model, with the devices applied as an adventitial wrap. Our results demonstrate a novel approach for sustained, local delivery of Resolvin D1 to vascular tissue at therapeutically relevant levels. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 31-41, 2017.
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Affiliation(s)
- Kevin D Lance
- UC Berkeley-UCSF Graduate Group in Bioengineering, San Francisco, California, 94158.,Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, 94158
| | - Anuran Chatterjee
- Cardiovascular Research Institute (CVRI) and Department of Surgery, University of California San Francisco, San Francisco, California, 94143
| | - Bian Wu
- Cardiovascular Research Institute (CVRI) and Department of Surgery, University of California San Francisco, San Francisco, California, 94143
| | - Giorgio Mottola
- Cardiovascular Research Institute (CVRI) and Department of Surgery, University of California San Francisco, San Francisco, California, 94143
| | - Harald Nuhn
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, 94158
| | - Phin Peng Lee
- UC Berkeley-UCSF Graduate Group in Bioengineering, San Francisco, California, 94158
| | - Brian E Sansbury
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard Institutes of Medicine HIM 830, Boston, Massachusetts, 02115
| | - Matthew Spite
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard Institutes of Medicine HIM 830, Boston, Massachusetts, 02115
| | - Tejal A Desai
- UC Berkeley-UCSF Graduate Group in Bioengineering, San Francisco, California, 94158.,Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, 94158
| | - Michael S Conte
- Cardiovascular Research Institute (CVRI) and Department of Surgery, University of California San Francisco, San Francisco, California, 94143
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60
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Fox CB, Cao Y, Nemeth CL, Chirra HD, Chevalier RW, Xu AM, Melosh NA, Desai TA. Fabrication of Sealed Nanostraw Microdevices for Oral Drug Delivery. ACS Nano 2016; 10:5873-81. [PMID: 27268699 PMCID: PMC5435488 DOI: 10.1021/acsnano.6b00809] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The oral route is preferred for systemic drug administration and provides direct access to diseased tissue of the gastrointestinal (GI) tract. However, many drugs have poor absorption upon oral administration due to damaging enzymatic and pH conditions, mucus and cellular permeation barriers, and limited time for drug dissolution. To overcome these limitations and enhance oral drug absorption, micron-scale devices with planar, asymmetric geometries, termed microdevices, have been designed to adhere to the lining of the GI tract and release drug at high concentrations directly toward GI epithelium. Here we seal microdevices with nanostraw membranes-porous nanostructured biomolecule delivery substrates-to enhance the properties of these devices. We demonstrate that the nanostraws facilitate facile drug loading and tunable drug release, limit the influx of external molecules into the sealed drug reservoir, and increase the adhesion of devices to epithelial tissue. These findings highlight the potential of nanostraw microdevices to enhance the oral absorption of a wide range of therapeutics by binding to the lining of the GI tract, providing prolonged and proximal drug release, and reducing the exposure of their payload to drug-degrading biomolecules.
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Affiliation(s)
- Cade B. Fox
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
| | - Yuhong Cao
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Cameron L. Nemeth
- Graduate Program in Bioengineering, University of California at Berkeley and San Francisco, UCSF Mission Bay Campus, San Francisco, California 94158, United States
| | - Hariharasudhan D. Chirra
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
| | - Rachel W. Chevalier
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
- Department of Pediatrics, Division of Pediatric Gastroenterology, School of Medicine, University of California, San Francisco, California 94158, United States
| | - Alexander M. Xu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Nicholas A. Melosh
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
- Graduate Program in Bioengineering, University of California at Berkeley and San Francisco, UCSF Mission Bay Campus, San Francisco, California 94158, United States
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61
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Huebsch N, Loskill P, Deveshwar N, Spencer CI, Judge LM, Mandegar MA, Fox CB, Mohamed TMA, Ma Z, Mathur A, Sheehan AM, Truong A, Saxton M, Yoo J, Srivastava D, Desai TA, So PL, Healy KE, Conklin BR. Miniaturized iPS-Cell-Derived Cardiac Muscles for Physiologically Relevant Drug Response Analyses. Sci Rep 2016; 6:24726. [PMID: 27095412 PMCID: PMC4837370 DOI: 10.1038/srep24726] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/05/2016] [Indexed: 01/16/2023] Open
Abstract
Tissue engineering approaches have the potential to increase the physiologic relevance of human iPS-derived cells, such as cardiomyocytes (iPS-CM). However, forming Engineered Heart Muscle (EHM) typically requires >1 million cells per tissue. Existing miniaturization strategies involve complex approaches not amenable to mass production, limiting the ability to use EHM for iPS-based disease modeling and drug screening. Micro-scale cardiospheres are easily produced, but do not facilitate assembly of elongated muscle or direct force measurements. Here we describe an approach that combines features of EHM and cardiospheres: Micro-Heart Muscle (μHM) arrays, in which elongated muscle fibers are formed in an easily fabricated template, with as few as 2,000 iPS-CM per individual tissue. Within μHM, iPS-CM exhibit uniaxial contractility and alignment, robust sarcomere assembly, and reduced variability and hypersensitivity in drug responsiveness, compared to monolayers with the same cellular composition. μHM mounted onto standard force measurement apparatus exhibited a robust Frank-Starling response to external stretch, and a dose-dependent inotropic response to the β-adrenergic agonist isoproterenol. Based on the ease of fabrication, the potential for mass production and the small number of cells required to form μHM, this system provides a potentially powerful tool to study cardiomyocyte maturation, disease and cardiotoxicology in vitro.
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Affiliation(s)
- Nathaniel Huebsch
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158.,Department of Pediatrics, University of California, San Francisco, CA 94143
| | - Peter Loskill
- Department of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, USA
| | - Nikhil Deveshwar
- Department of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA
| | - C Ian Spencer
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Luke M Judge
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158.,Department of Pediatrics, University of California, San Francisco, CA 94143
| | | | - Cade B Fox
- University of California, San Francisco, Schools of Pharmacy and Medicine, Department of Bioengineering and Therapeutic Sciences, San Francisco, CA 94158
| | - Tamer M A Mohamed
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158.,Institute of Cardiovascular Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,Faculty of Pharmacy, Zagazig University, EL-Sharkiak, Egypt
| | - Zhen Ma
- Department of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, USA
| | - Anurag Mathur
- Department of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, USA
| | - Alice M Sheehan
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Annie Truong
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Mike Saxton
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Jennie Yoo
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Deepak Srivastava
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158.,Department of Pediatrics, University of California, San Francisco, CA 94143
| | - Tejal A Desai
- University of California, San Francisco, Schools of Pharmacy and Medicine, Department of Bioengineering and Therapeutic Sciences, San Francisco, CA 94158
| | - Po-Lin So
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Kevin E Healy
- Department of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, USA
| | - Bruce R Conklin
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158.,Departments of Medicine, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
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62
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Lance KD, Good SD, Mendes TS, Ishikiriyama M, Chew P, Estes LS, Yamada K, Mudumba S, Bhisitkul RB, Desai TA. In Vitro and In Vivo Sustained Zero-Order Delivery of Rapamycin (Sirolimus) From a Biodegradable Intraocular Device. Invest Ophthalmol Vis Sci 2016; 56:7331-7. [PMID: 26559479 DOI: 10.1167/iovs.15-17757] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE We created implantable intraocular devices capable of constant and continuous rapamycin release on the scale of months to years. METHODS Polycaprolactone (PCL) thin films were used to encapsulate rapamycin to create implantable and biodegradable intraocular devices. Different film devices were studied by modifying the size, thickness, and porosity of the PCL films. RESULTS In vitro release of rapamycin was observed to be constant (zero-order) through 14 weeks of study. Release rates were tunable by altering PCL film porosity and thickness. In vivo release of rapamycin was observed out through 16 weeks with concentrations in the retina-choroid in the therapeutic range. Rapamycin concentration in the blood was below the lower limit of quantification. The drug remaining in the device was chemically stable in vitro and in vivo, and was sufficient to last for upwards of 2 years of total release. The mechanism of release is related to the dissolution kinetics of crystalline rapamycin. CONCLUSIONS Microporous PCL thin film devices demonstrate good ocular compatibility and the ability to release rapamycin locally to the eye over the course of many weeks.
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Affiliation(s)
- Kevin D Lance
- University of California at Berkeley-University of California, San Francisco Bioengineering Graduate Program, San Francisco, California, United States
| | - Samuel D Good
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Thaís S Mendes
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Mynna Ishikiriyama
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Patrick Chew
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States
| | - Laurel S Estes
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States
| | - Kazuhito Yamada
- Pharmaceutical Development Group, Pharmaceutical Development Center, Santen Pharmaceutical Co., Ltd., Nara, Japan
| | - Sri Mudumba
- Pharmaceutical Development, Santen, Inc., Emeryville, California, United States
| | - Robert B Bhisitkul
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Tejal A Desai
- University of California at Berkeley-University of California, San Francisco Bioengineering Graduate Program, San Francisco, California, United States 3Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Fra
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63
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Abstract
Current approaches to reducing restenosis do not balance the reduction of vascular smooth muscle cell proliferation with the increase in the healing of the endothelium. Building on our previous work, we present our study on the effects of Nitinol-based nanotubular coatings with different nanotube diameters on the reduction of restenosis. Here, we demonstrate that the nanotubular coatings reduced primary human aortic smooth muscle cell (HASMC) proliferation and increased the migration (by more than 4 times), collagen (by 2-3 times per cell) and elastin (by 5-8 times per cell) production of primary human aortic endothelial cells (HAEC). Furthermore, a significant increase in elastin and soluble collagen production of HAEC was observed with an increase in nanotube diameter. Our findings suggest that nanotubes-coated Nitinol may provide a surface conducive for HAEC reendothelialization while reducing the proliferation of HASMC.
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Affiliation(s)
- Phin P Lee
- Department of Bioengineering and Therapeutic Sciences and The UC Berkeley-UCSF Graduate Group in Bioengineering, University of California-San Francisco, San Francisco, California 94158, United States
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences and The UC Berkeley-UCSF Graduate Group in Bioengineering, University of California-San Francisco, San Francisco, California 94158, United States
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64
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Genchi GG, Nuhn H, Liakos I, Marino A, Marras S, Athanassiou A, Mattoli V, Desai TA. Titanium dioxide nanotube arrays coated with laminin enhance C2C12 skeletal myoblast adhesion and differentiation. RSC Adv 2016. [DOI: 10.1039/c6ra00716c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
TiO2 nanotube arrays of various topography/surface chemistry are tested with C2C12 cells. Improved cell adhesion and differentiation are shown on 10 nm diameter nanotube arrays coated with laminin, encouraging array use for skeletal muscle tissue engineering and stimulation.
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Affiliation(s)
- Giada G. Genchi
- Center for Micro-BioRobotics @SSSA
- Istituto Italiano di Tecnologia
- 56025 Pontedera
- Italy
- Department of Bioengineering and Therapeutic Sciences
| | - Harald Nuhn
- Department of Bioengineering and Therapeutic Sciences
- University of California
- San Francisco
- USA
| | - Ioannis Liakos
- Smart Materials
- Nanophysics Department
- Istituto Italiano di Tecnologia
- Genoa
- Italy
| | - Attilio Marino
- Center for Micro-BioRobotics @SSSA
- Istituto Italiano di Tecnologia
- 56025 Pontedera
- Italy
- The BioRobotics Institute
| | - Sergio Marras
- Nanochemistry Department
- Istituto Italiano di Tecnologia
- Genoa
- Italy
| | | | - Virgilio Mattoli
- Center for Micro-BioRobotics @SSSA
- Istituto Italiano di Tecnologia
- 56025 Pontedera
- Italy
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences
- University of California
- San Francisco
- USA
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65
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Abstract
Refinement of micro- and nanofabrication in the semiconductor field has led to innovations in biomedical technologies. Nanotopography, in particular, shows great potential in facilitating drug delivery. The flexibility of fabrication techniques has created a diverse array of topographies that have been developed for drug delivery applications. Nanowires and nanostraws deliver drug cytosolically for in vitro and ex vivo applications. In vivo drug delivery is limited by the barrier function of the epithelium. Nanowires on microspheres increase adhesion and residence time for oral drug delivery, while also increasing permeability of the epithelium. Low aspect ratio nanocolumns increase paracellular permeability, and in conjunction with microneedles increase transdermal drug delivery of biologics in vivo. In summary, nanotopography is a versatile tool for drug delivery. It can deliver directly to cells or be used for in vivo delivery across epithelial barriers. This editorial highlights the application of nanotopography in the field of drug delivery.
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Affiliation(s)
- Laura A Walsh
- a UC Berkeley & UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus , San Francisco , CA 94158 , USA
| | - Jessica L Allen
- b Department of Bioengineering and Therapeutic Sciences , University of California , San Francisco , CA 94158 , USA
| | - Tejal A Desai
- b Department of Bioengineering and Therapeutic Sciences , University of California , San Francisco , CA 94158 , USA
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66
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Todhunter ME, Jee NY, Hughes AJ, Coyle MC, Cerchiari A, Farlow J, Garbe JC, LaBarge MA, Desai TA, Gartner ZJ. Programmed synthesis of three-dimensional tissues. Nat Methods 2015; 12:975-81. [PMID: 26322836 PMCID: PMC4589502 DOI: 10.1038/nmeth.3553] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/17/2015] [Indexed: 12/31/2022]
Abstract
Reconstituting tissues from their cellular building blocks facilitates the modeling of morphogenesis, homeostasis and disease in vitro. Here we describe DNA-programmed assembly of cells (DPAC), a method to reconstitute the multicellular organization of organoid-like tissues having programmed size, shape, composition and spatial heterogeneity. DPAC uses dissociated cells that are chemically functionalized with degradable oligonucleotide 'Velcro', allowing rapid, specific and reversible cell adhesion to other surfaces coated with complementary DNA sequences. DNA-patterned substrates function as removable and adhesive templates, and layer-by-layer DNA-programmed assembly builds arrays of tissues into the third dimension above the template. DNase releases completed arrays of organoid-like microtissues from the template concomitant with full embedding in a variety of extracellular matrix (ECM) gels. DPAC positions subpopulations of cells with single-cell spatial resolution and generates cultures several centimeters long. We used DPAC to explore the impact of ECM composition, heterotypic cell-cell interactions and patterns of signaling heterogeneity on collective cell behaviors.
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Affiliation(s)
- Michael E Todhunter
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA
| | - Noel Y Jee
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Chemistry &Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, California, USA
| | - Alex J Hughes
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Maxwell C Coyle
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Alec Cerchiari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Graduate Program in Bioengineering, University of California, Berkeley, and University of California, San Francisco, Berkeley, California, USA
| | - Justin Farlow
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA
| | - James C Garbe
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Mark A LaBarge
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Tejal A Desai
- Chemistry &Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, California, USA.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Graduate Program in Bioengineering, University of California, Berkeley, and University of California, San Francisco, Berkeley, California, USA
| | - Zev J Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA.,Chemistry &Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, California, USA.,Graduate Program in Bioengineering, University of California, Berkeley, and University of California, San Francisco, Berkeley, California, USA.,Center for Systems and Synthetic Biology, University of California, San Francisco, San Francisco, California, USA
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67
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Fox CB, Kim J, Le LV, Nemeth CL, Chirra HD, Desai TA. Micro/nanofabricated platforms for oral drug delivery. J Control Release 2015; 219:431-444. [PMID: 26244713 DOI: 10.1016/j.jconrel.2015.07.033] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 12/18/2022]
Abstract
The oral route of drug administration is most preferred due to its ease of use, low cost, and high patient compliance. However, the oral uptake of many small molecule drugs and biotherapeutics is limited by various physiological barriers, and, as a result, drugs suffer from issues with low solubility, low permeability, and degradation following oral administration. The flexibility of micro- and nanofabrication techniques has been used to create drug delivery platforms designed to address these barriers to oral drug uptake. Specifically, micro/nanofabricated devices have been designed with planar, asymmetric geometries to promote device adhesion and unidirectional drug release toward epithelial tissue, thereby prolonging drug exposure and increasing drug permeation. Furthermore, surface functionalization, nanotopography, responsive drug release, motion-based responses, and permeation enhancers have been incorporated into such platforms to further enhance drug uptake. This review will outline the application of micro/nanotechnology to specifically address the physiological barriers to oral drug delivery and highlight technologies that may be incorporated into these oral drug delivery systems to further enhance drug uptake.
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Affiliation(s)
- Cade B Fox
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Jean Kim
- UC Berkeley & UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158, USA
| | - Long V Le
- UC Berkeley & UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158, USA
| | - Cameron L Nemeth
- UC Berkeley & UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158, USA
| | - Hariharasudhan D Chirra
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA; UC Berkeley & UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, CA 94158, USA.
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68
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Schlesinger E, Ciaccio N, Desai TA. Polycaprolactone thin-film drug delivery systems: Empirical and predictive models for device design. Mater Sci Eng C Mater Biol Appl 2015; 57:232-9. [PMID: 26354259 DOI: 10.1016/j.msec.2015.07.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 07/11/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To define empirical models and parameters based on theoretical equations to describe drug release profiles from two polycaprolactone thin-film drug delivery systems. Additionally, to develop a predictive model for empirical parameters based on drugs' physicochemical properties. METHODS Release profiles from a selection of drugs representing the standard pharmaceutical space in both polycaprolactone matrix and reservoir systems were determined experimentally. The proposed models were used to calculate empirical parameters describing drug diffusion and release. Observed correlations between empirical parameters and drug properties were used to develop equations to predict parameters based on drug properties. Predictive and empirical models were evaluated in the design of three prototype devices: a levonorgestrel matrix system for on-demand locally administered contraception, a timolol-maleate reservoir system for glaucoma treatment, and a primaquine-bisphosphate reservoir system for malaria prophylaxis. RESULTS Proposed empirical equations accurately fit experimental data. Experimentally derived empirical parameters show significant correlations with LogP, molecular weight, and solubility. Empirical models based on predicted parameters accurately predict experimental release data for three prototype systems, demonstrating the accuracy and utility of these models. CONCLUSION The proposed empirical models can be used to design polycaprolactone thin-film devices for target geometries and release rates. Empirical parameters can be predicted based on drug properties. Together, these models provide tools for preliminary evaluation and design of controlled-release delivery systems.
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Affiliation(s)
- Erica Schlesinger
- University of California, Berkeley-University of California San Francisco Graduate Program in Bioengineering, CA, USA
| | - Natalie Ciaccio
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA; BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Tejal A Desai
- University of California, Berkeley-University of California San Francisco Graduate Program in Bioengineering, CA, USA; Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
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69
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Fox CB, Chirra HD, Desai TA. Planar bioadhesive microdevices: a new technology for oral drug delivery. Curr Pharm Biotechnol 2015; 15:673-83. [PMID: 25219863 DOI: 10.2174/1389201015666140915152706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 06/01/2014] [Accepted: 06/23/2014] [Indexed: 12/12/2022]
Abstract
The oral route is the most convenient and least expensive route of drug administration. Yet, it is accompanied by many physiological barriers to drug uptake including low stomach pH, intestinal enzymes and transporters, mucosal barriers, and high intestinal fluid shear. While many drug delivery systems have been developed for oral drug administration, the physiological components of the gastro intestinal tract remain formidable barriers to drug uptake. Recently, microfabrication techniques have been applied to create micron-scale devices for oral drug delivery with a high degree of control over microdevice size, shape, chemical composition, drug release profile, and targeting ability. With precise control over device properties, microdevices can be fabricated with characteristics that provide increased adhesion for prolonged drug exposure, unidirectional release which serves to avoid luminal drug loss and enhance drug permeation, and protection of a drug payload from the harsh environment of the intestinal tract. Here we review the recent developments in microdevice technology and discuss the potential of these devices to overcome unsolved challenges in oral drug delivery.
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Affiliation(s)
| | | | - Tejal A Desai
- 1700 4th Street, Byers Hall 204, Box 2520, San Francisco, CA 94158, USA.
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70
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Wu B, Lance KD, Chatterjee A, Mottola G, Chen M, Komshian SR, Desai TA, Conte MS. Abstract 300: A Biodegradable Wrap for Peri-vascular Delivery of Pro-resolving Lipid Mediators. Arterioscler Thromb Vasc Biol 2015. [DOI: 10.1161/atvb.35.suppl_1.300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
Persistent inflammation following vascular injury leads to excessive scarring, limiting the success of vascular interventions. Recent work has identified that endogenous specialized proresolving lipid mediators (SPM) such as resolvin D1 (RvD1) actively orchestrate the process of resolution, exerting vasculo-protective effects without associated toxicity. We propose local vascular delivery of SPM through a biodegradable wrap.
Methods:
RvD1 (200 ng) was heat-sealed between thin layers of polycaprolactone (PCL) or poly-lactic-co-glycolic acid (PLGA). PLGA membranes differed in their composition of lactic versus glycolic acid (%-lactide). Directional drug release was measured via EIA in a cell-free system in vitro and into rabbit aortas exposed to pulsatile flow ex vivo. Bioactivity was confirmed on human vascular smooth muscle cells (VSMC) using migration and proliferation assays.
Results:
Of the constructs tested, a 3-layered PLGA wrap consisting of 85%/75%/50%-lactide provided the most favorable drug elution (Fig1a), with sustained release of >800 pg/day for at least 14 days and nearly all elution occurring from the 50%-lactide side (Fig1b). Perivascular application of this wrap ex vivo with the 50%-lactide side facing “in” demonstrated uptake into rabbit aortic walls at 8 hours (0.4 ± 0.1 pg/mg). VSMC cultures exposed to drug-loaded wraps showed inhibition of migration (40%) and proliferation (25%).
Conclusion:
We demonstrate sustained and directional elution of therapeutically relevant amounts of biologically-active RvD1 through a biodegradable perivascular wrap, providing opportunity for translational studies of SPM in vascular injury.
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Affiliation(s)
- Bian Wu
- Surgery, Univ of California, San Francisco, San Francisco, CA
| | - Kevin D Lance
- Bioengineering, Univ of California, San Francisco, San Francisco, CA
| | | | - Giorgio Mottola
- Surgery, Univ of California, San Francisco, San Francisco, CA
| | - Mian Chen
- Surgery, Univ of California, San Francisco, San Francisco, CA
| | | | - Tejal A Desai
- Bioengineering, Univ of California, San Francisco, San Francisco, CA
| | - Michael S Conte
- Surgery, Univ of California, San Francisco, San Francisco, CA
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71
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Peña JR, Pinney JR, Ayala P, Desai TA, Goldspink PH. Localized delivery of mechano-growth factor E-domain peptide via polymeric microstructures improves cardiac function following myocardial infarction. Biomaterials 2015; 46:26-34. [PMID: 25678113 PMCID: PMC4328136 DOI: 10.1016/j.biomaterials.2014.12.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/09/2014] [Accepted: 12/22/2014] [Indexed: 01/28/2023]
Abstract
The Insulin like growth factor-I isoform mechano-growth factor (MGF), is expressed in the heart following myocardial infarction and encodes a unique E-domain region. To examine E-domain function, we delivered a synthetic peptide corresponding to the unique E-domain region of the human MGF (IGF-1Ec) via peptide eluting polymeric microstructures to the heart. The microstructures were made of poly (ethylene glycol) dimethacrylate hydrogel and bioengineered to be the same size as an adult cardiac myocyte (100 × 15 × 15 μm) and with a stiffness of 20 kPa. Peptide eluting microrods and empty microrods were delivered via intramuscular injection following coronary artery ligation in mice. To examine the physiologic consequences, we assessed the impact of peptide delivery on cardiac function and cardiovascular hemodynamics using pressure-volume loops and gene expression by quantitative RT-PCR. A significant decline in both systolic and diastolic function accompanied by pathologic hypertrophy occurred by 2 weeks which decompensated further by 10 weeks post-infarct in the untreated groups. Delivery of the E-domain peptide eluting microrods decreased mortality, ameliorated the decline in hemodynamics, and delayed decompensation. This was associated with the inhibition of pathologic hypertrophy despite increasing vascular impedance. Delivery of the empty microrods had limited effects on hemodynamics and while pathologic hypertrophy persisted there was a decrease in ventricular stiffness. Our data show that cardiac restricted administration of the MGF E-domain peptide using polymeric microstructures may be used to prevent adverse remodeling of the heart and improve function following myocardial infarction.
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Affiliation(s)
- James R Peña
- Department of Physiology & Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - James R Pinney
- UCSF Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Perla Ayala
- UC Berkeley-UCSF Graduate Group in Bioengineering, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tejal A Desai
- UC Berkeley-UCSF Graduate Group in Bioengineering, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Paul H Goldspink
- Department of Physiology & Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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72
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Fox CB, Kim J, Schlesinger EB, Chirra HD, Desai TA. Fabrication of micropatterned polymeric nanowire arrays for high-resolution reagent localization and topographical cellular control. Nano Lett 2015; 15:1540-6. [PMID: 25639724 PMCID: PMC4664059 DOI: 10.1021/nl503872p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Herein, we present a novel approach for the fabrication of micropatterned polymeric nanowire arrays that addresses the current need for scalable and customizable polymer nanofabrication. We describe two variations of this approach for the patterning of nanowire arrays on either flat polymeric films or discrete polymeric microstructures and go on to investigate biological applications for the resulting polymeric features. We demonstrate that the micropatterned arrays of densely packed nanowires facilitate rapid, low-waste drug and reagent localization with micron-scale resolution as a result of their high wettability. We also show that micropatterned nanowire arrays provide hierarchical cellular control by simultaneously directing cell shape on the micron scale and influencing focal adhesion formation on the nanoscale. This nanofabrication approach has potential applications in scaffold-based cellular control, biological assay miniaturization, and biomedical microdevice technology.
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Affiliation(s)
- Cade B. Fox
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
| | - Jean Kim
- UC Berkeley and UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, California 94158, United States
| | - Erica B. Schlesinger
- UC Berkeley and UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, California 94158, United States
| | - Hariharasudhan D. Chirra
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
- UC Berkeley and UCSF Graduate Program in Bioengineering, UCSF Mission Bay Campus, San Francisco, California 94158, United States
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73
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Cerchiari AE, Garbe JC, Jee NY, Todhunter ME, Broaders KE, Peehl DM, Desai TA, LaBarge MA, Thomson M, Gartner ZJ. A strategy for tissue self-organization that is robust to cellular heterogeneity and plasticity. Proc Natl Acad Sci U S A 2015; 112:2287-92. [PMID: 25633040 PMCID: PMC4343104 DOI: 10.1073/pnas.1410776112] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Developing tissues contain motile populations of cells that can self-organize into spatially ordered tissues based on differences in their interfacial surface energies. However, it is unclear how self-organization by this mechanism remains robust when interfacial energies become heterogeneous in either time or space. The ducts and acini of the human mammary gland are prototypical heterogeneous and dynamic tissues comprising two concentrically arranged cell types. To investigate the consequences of cellular heterogeneity and plasticity on cell positioning in the mammary gland, we reconstituted its self-organization from aggregates of primary cells in vitro. We find that self-organization is dominated by the interfacial energy of the tissue-ECM boundary, rather than by differential homo- and heterotypic energies of cell-cell interaction. Surprisingly, interactions with the tissue-ECM boundary are binary, in that only one cell type interacts appreciably with the boundary. Using mathematical modeling and cell-type-specific knockdown of key regulators of cell-cell cohesion, we show that this strategy of self-organization is robust to severe perturbations affecting cell-cell contact formation. We also find that this mechanism of self-organization is conserved in the human prostate. Therefore, a binary interfacial interaction with the tissue boundary provides a flexible and generalizable strategy for forming and maintaining the structure of two-component tissues that exhibit abundant heterogeneity and plasticity. Our model also predicts that mutations affecting binary cell-ECM interactions are catastrophic and could contribute to loss of tissue architecture in diseases such as breast cancer.
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Affiliation(s)
- Alec E Cerchiari
- University of California at Berkeley-University of California at San Francisco Graduate Program in Bioengineering, University of California, Berkeley, CA 94720; Departments of Bioengineering and Therapeutic Sciences and Pharmaceutical Chemistry, and
| | - James C Garbe
- Departments of Bioengineering and Therapeutic Sciences and Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | | | | | | | - Donna M Peehl
- Stanford University School of Medicine, Stanford University, Palo Alto, CA 94305
| | - Tejal A Desai
- University of California at Berkeley-University of California at San Francisco Graduate Program in Bioengineering, University of California, Berkeley, CA 94720; Departments of Bioengineering and Therapeutic Sciences and
| | - Mark A LaBarge
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Matthew Thomson
- Center for Systems and Synthetic Biology, University of California, San Francisco, CA 94143
| | - Zev J Gartner
- University of California at Berkeley-University of California at San Francisco Graduate Program in Bioengineering, University of California, Berkeley, CA 94720; Pharmaceutical Chemistry, and Center for Systems and Synthetic Biology, University of California, San Francisco, CA 94143;
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74
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Silvestrini MT, Yin D, Martin AJ, Coppes VG, Mann P, Larson PS, Starr PA, Zeng X, Gupta N, Panter SS, Desai TA, Lim DA. Interventional magnetic resonance imaging-guided cell transplantation into the brain with radially branched deployment. Mol Ther 2015; 23:119-29. [PMID: 25138755 PMCID: PMC4426791 DOI: 10.1038/mt.2014.155] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/09/2014] [Indexed: 01/06/2023] Open
Abstract
Intracerebral cell transplantation is being pursued as a treatment for many neurological diseases, and effective cell delivery is critical for clinical success. To facilitate intracerebral cell transplantation at the scale and complexity of the human brain, we developed a platform technology that enables radially branched deployment (RBD) of cells to multiple target locations at variable radial distances and depths along the initial brain penetration tract with real-time interventional magnetic resonance image (iMRI) guidance. iMRI-guided RBD functioned as an "add-on" to standard neurosurgical and imaging workflows, and procedures were performed in a commonly available clinical MRI scanner. Multiple deposits of super paramagnetic iron oxide beads were safely delivered to the striatum of live swine, and distribution to the entire putamen was achieved via a single cannula insertion in human cadaveric heads. Human embryonic stem cell-derived dopaminergic neurons were biocompatible with the iMRI-guided RBD platform and successfully delivered with iMRI guidance into the swine striatum. Thus, iMRI-guided RBD overcomes some of the technical limitations inherent to the use of straight cannulas and standard stereotactic targeting. This platform technology could have a major impact on the clinical translation of a wide range of cell therapeutics for the treatment of many neurological diseases.
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Affiliation(s)
- Matthew T Silvestrini
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Present address: Department of Bioengineering, University of California, Davis, Davis, California, USA
| | - Dali Yin
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Alastair J Martin
- Department of Radiology, University of California, San Francisco, San Francisco, California, USA
| | - Valerie G Coppes
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Department of Surgery, Veteran's Affairs Medical Center, San Francisco, California, USA
| | - Preeti Mann
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Department of Surgery, Veteran's Affairs Medical Center, San Francisco, California, USA
| | - Paul S Larson
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Department of Surgery, Veteran's Affairs Medical Center, San Francisco, California, USA
| | - Philip A Starr
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Xianmin Zeng
- Buck Institute for Research on Aging, Novato, California, USA
| | - Nalin Gupta
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
| | - S S Panter
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Department of Surgery, Veteran's Affairs Medical Center, San Francisco, California, USA
| | - Tejal A Desai
- Department of Bioengineering, University of California, San Francisco, San Francisco, California, USA
| | - Daniel A Lim
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA
- Department of Surgery, Veteran's Affairs Medical Center, San Francisco, California, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF, San Francisco, California, USA
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75
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Cerchiari A, Garbe JC, Todhunter ME, Jee NY, Pinney JR, LaBarge MA, Desai TA, Gartner ZJ. Formation of spatially and geometrically controlled three-dimensional tissues in soft gels by sacrificial micromolding. Tissue Eng Part C Methods 2014; 21:541-7. [PMID: 25351430 DOI: 10.1089/ten.tec.2014.0450] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Patterned three-dimensional (3D) cell culture models aim to more accurately represent the in vivo architecture of a tissue for the purposes of testing drugs, studying multicellular biology, or engineering functional tissues. However, patterning 3D multicellular structures within very soft hydrogels (<500 Pa) that mimic the physicochemical environment of many tissues remains a challenge for existing methods. To overcome this challenge, we use a Sacrificial Micromolding technique to temporarily form spatially and geometrically defined 3D cell aggregates in degradable scaffolds before transferring and culturing them in a reconstituted extracellular matrix. Herein, we demonstrate that Sacrificial Micromolding (1) promotes cyst formation and proper polarization of established epithelial cell lines, (2) allows reconstitution of heterotypic cell-cell interactions in multicomponent epithelia, and (3) can be used to control the lumenization-state of epithelial cysts as a function of tissue size. In addition, we discuss the potential of Sacrificial Micromolding as a cell-patterning tool for future studies.
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Affiliation(s)
- Alec Cerchiari
- 1UC Berkeley-UCSF Graduate Program in Bioengineering, Department of Bioengineering, University of California Berkeley, Berkeley, California.,6Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California
| | - James C Garbe
- 2Lawrence Berkeley National Lab, Berkeley, California
| | - Michael E Todhunter
- 3TETRAD Graduate Program, University of California San Francisco, San Francisco, California.,4Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California
| | - Noel Y Jee
- 4Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California.,5Chemistry and Chemical Biology Graduate Program, University of California San Francisco, San Francisco, California
| | - James R Pinney
- 1UC Berkeley-UCSF Graduate Program in Bioengineering, Department of Bioengineering, University of California Berkeley, Berkeley, California.,6Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California
| | | | - Tejal A Desai
- 1UC Berkeley-UCSF Graduate Program in Bioengineering, Department of Bioengineering, University of California Berkeley, Berkeley, California.,5Chemistry and Chemical Biology Graduate Program, University of California San Francisco, San Francisco, California.,6Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California
| | - Zev J Gartner
- 1UC Berkeley-UCSF Graduate Program in Bioengineering, Department of Bioengineering, University of California Berkeley, Berkeley, California.,3TETRAD Graduate Program, University of California San Francisco, San Francisco, California.,4Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California.,7University of California San Francisco Center for Systems and Synthetic Biology, San Francisco, California
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76
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Abstract
INTRODUCTION The ongoing surge of resistance of bacterial pathogens to antibiotic therapies and the consistently aging median member of the human race signal an impending increase in the incidence of chronic bone infection. Nanotechnological platforms for local and sustained delivery of therapeutics hold the greatest potential for providing minimally invasive and maximally regenerative therapies for this rare but persistent condition. AREAS COVERED Shortcomings of the clinically available treatment options, including poly(methyl methacrylate) beads and calcium sulfate cements, are discussed and their transcending using calcium-phosphate/polymeric nanoparticulate composites is foreseen. Bone is a composite wherein the weakness of each component alone is compensated for by the strength of its complement and an ideal bone substitute should be fundamentally the same. EXPERT OPINION Discrepancy between in vitro and in vivo bioactivity assessments is highlighted, alongside the inherent imperfectness of the former. Challenges entailing the cross-disciplinary nature of engineering a new generation of drug delivery vehicles are delineated and it is concluded that the future for the nanoparticulate therapeutic carriers belongs to multifunctional, synergistic and theranostic composites capable of simultaneously targeting, monitoring and treating internal organismic disturbances in a smart, feedback fashion and in direct response to the demands of the local environment.
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Affiliation(s)
- Vuk Uskoković
- University of Illinois, Department of Bioengineering, Advanced Materials and Bionanotechnology Laboratory, Chicago, IL 60607-7052, USA
| | - Tejal A Desai
- University of California, Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, San Francisco, CA 94158-2330, USA
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77
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Weber RJ, Liang SI, Selden NS, Desai TA, Gartner ZJ. Efficient targeting of fatty-acid modified oligonucleotides to live cell membranes through stepwise assembly. Biomacromolecules 2014; 15:4621-6. [PMID: 25325667 PMCID: PMC4261982 DOI: 10.1021/bm501467h] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Lipid
modifications provide efficient targeting of oligonucleotides
to live cell membranes in a range of applications. Targeting efficiency
is a function of the rate of lipid DNA insertion into the cell surface
and its persistence over time. Here we show that increasing lipid
hydrophobicity increases membrane persistence, but decreases the rate
of membrane insertion due to the formation of nonproductive aggregates
in solution. To ameliorate this effect, we split the net hydrophobicity
of the membrane anchor between two complementary oligonucleotides.
When prehybridized in solution, doubly anchored molecules also aggregate
due to their elevated hydrophobicity. However, when added sequentially
to cells, aggregation does not occur so membrane insertion is efficient.
Hybridization between the two strands locks the complexes at the cell
surface by increasing net hydrophobicity, increasing their total concentration
and lifetime, and dramatically improving their utility in a variety
of biomedical applications.
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Affiliation(s)
- Robert J Weber
- Department of Pharmaceutical Chemistry, University of California, San Francisco , 600 16th Street, Box 2280, San Francisco, California 94158, United States
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78
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Doroudian G, Pinney J, Ayala P, Los T, Desai TA, Russell B. Sustained delivery of MGF peptide from microrods attracts stem cells and reduces apoptosis of myocytes. Biomed Microdevices 2014; 16:705-15. [PMID: 24908137 PMCID: PMC4418932 DOI: 10.1007/s10544-014-9875-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Local release of drugs may have many advantages for tissue repair but also presents major challenges. Bioengineering approaches allow microstructures to be fabricated that contain bioactive peptides for sustained local delivery. Heart tissue damage is associated with local increases in mechano growth factor (MGF), a member of the IGF-1 family. The E domain of MGF peptide is anti-apoptotic and a stem cell homing factor. The objectives of this study were to fabricate a microrod delivery device of poly (ethylene glycol) dimethacrylate (PEGDMA) hydrogel loaded with MGF peptide and to determine the elution profile and bioactivity of MGF. The injectable microrods are 30 kPa stiffness and 15 μm widths by 100 μm lengths, chosen to match heart stiffness and myocyte size. Successful encapsulation of native MGF peptide within microrods was achieved with delivery of MGF for 2 weeks, as measured by HPLC. Migration of human mesenchymal stem cells (hMSCs) increased with MGF microrod treatment (1.72 ± 0.23, p < 0.05). Inhibition of the apoptotic pathway in neonatal rat ventricular myocytes was induced by 8 h of hypoxia (1 % O2). Protection from apoptosis by MGF microrod treatment was shown by the TUNEL assay and increased Bcl-2 expression (2 ± 0.19, p < 0.05). Microrods without MGF regulated the cytoskeleton, adhesion, and proliferation of hMSCs, and MGF had no effect on these properties. Therefore, the combination microdevice provided both the mechanical cues and 2-week MGF bioactivity to reduce apoptosis and recruit stem cells, suggesting potential use of MGF microrods for cardiac regeneration therapy in vivo.
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Affiliation(s)
- Golnar Doroudian
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - James Pinney
- Department of Physiology and Division of Bioengineering, University of California at San Francisco, San Francisco, CA, USA
| | - Perla Ayala
- Department of Physiology and Division of Bioengineering, University of California at San Francisco, San Francisco, CA, USA
| | - Tamara Los
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott, Chicago, IL 60612, USA
| | - Tejal A. Desai
- Department of Physiology and Division of Bioengineering, University of California at San Francisco, San Francisco, CA, USA
| | - Brenda Russell
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott, Chicago, IL 60612, USA
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79
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Chirra HD, Shao L, Ciaccio N, Fox CB, Wade JM, Ma A, Desai TA. Planar microdevices for enhanced in vivo retention and oral bioavailability of poorly permeable drugs. Adv Healthc Mater 2014; 3:1648-54. [PMID: 24711341 DOI: 10.1002/adhm.201300676] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/07/2014] [Indexed: 11/09/2022]
Abstract
The development of novel oral drug delivery platforms for administering therapeutics in a safe and effective manner through the harsh gastrointestinal environment is of great importance. Here, the use of engineered thin planar poly(methyl methacrylate) (PMMA) microdevices is tested to enhance oral bioavailability of acyclovir, a poorly permeable drug. Acyclovir is loaded into the unidirectional drug releasing microdevice reservoirs using a drug entrapping photocross-linkable hydrogel matrix. An increase in acyclovir permeation across in vitro caco-2 monolayer is seen in the presence of microdevices as compared with acyclovir-entrapped hydrogels or free acyclovir solution. Cell proliferation studies show that microdevices are relatively nontoxic in nature for use in in vivo studies. Enhanced in vivo retention of microdevices is observed as their thin side walls experience minimal peristaltic shear stress as compared with spherical microparticles. Unidirectional acyclovir release and enhanced retention of microdevices achieve a 4.5-fold increase in bioavailability in vivo as compared with an oral gavage of acyclovir solution with the same drug mass. The enhanced oral bioavailability results suggest that thin, planar, bioadhesive, and unidirectional drug releasing microdevices will significantly improve the systemic and localized delivery of a broad range of oral therapeutics in the near future.
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Affiliation(s)
- Hariharasudhan D. Chirra
- Department of Bioengineering and Therapeutic Sciences; University of California; 1700 4th Street, Byers Hall 204, Box 2520 San Francisco CA 94158 USA
| | - Ling Shao
- Division of Gastroenterology, Department of Medicine; University of California; 513 Parnassus Ave San Francisco CA 94143 USA
| | - Natalie Ciaccio
- Department of Bioengineering and Therapeutic Sciences; University of California; 1700 4th Street, Byers Hall 204, Box 2520 San Francisco CA 94158 USA
| | - Cade B. Fox
- Department of Bioengineering and Therapeutic Sciences; University of California; 1700 4th Street, Byers Hall 204, Box 2520 San Francisco CA 94158 USA
| | - Jennifer M. Wade
- Department of Bioengineering and Therapeutic Sciences; University of California; 1700 4th Street, Byers Hall 204, Box 2520 San Francisco CA 94158 USA
| | - Averil Ma
- Division of Gastroenterology, Department of Medicine; University of California; 513 Parnassus Ave San Francisco CA 94143 USA
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences; University of California; 1700 4th Street, Byers Hall 204, Box 2520 San Francisco CA 94158 USA
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80
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Abstract
In this study, we describe the synthesis of an upright nanotubular coating with discrete, exposed nanotubes on top of superelastic Nitinol via anodization and characterization of the surface elemental composition and nickel release rates. We demonstrate, for the first time, that this coating could improve re-endothelialization by increasing the cell spreading and migration of primary human aortic endothelial cells on Nitinol. We also show the potential for reducing neointimal hyperplasia by decreasing the proliferation and expression of collagen I and MMP-2 in primary human aortic smooth muscle cells (HASMC). Furthermore, we did not observe the nanotubular surface to induce inflammation through ICAM-1 expression in HASMC as compared to the flat control. This coating could be used to improve Nitinol stents by reducing restenosis rates and, given the extensive use of Nitinol in other implantable devices, act as a generalized coating strategy for other medical devices.
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Affiliation(s)
- Phin P. Lee
- Department of Bioengineering and Therapeutic Sciences, University of California—San Francisco, San Francisco, California 94158, United States
- The UC Berkeley–UCSF Graduate Group in Bioengineering, University of California—San Francisco, San Francisco, California 94158, United States
| | - Alec Cerchiari
- Department of Bioengineering and Therapeutic Sciences, University of California—San Francisco, San Francisco, California 94158, United States
- The UC Berkeley–UCSF Graduate Group in Bioengineering, University of California—San Francisco, San Francisco, California 94158, United States
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences, University of California—San Francisco, San Francisco, California 94158, United States
- The UC Berkeley–UCSF Graduate Group in Bioengineering, University of California—San Francisco, San Francisco, California 94158, United States
- Corresponding Author:. Phone: 415-514-4503. Fax: 415-476-2414
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81
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Pinney JR, Melkus G, Cerchiari A, Hawkins J, Desai TA. Novel functionalization of discrete polymeric biomaterial microstructures for applications in imaging and three-dimensional manipulation. ACS Appl Mater Interfaces 2014; 6:14477-14485. [PMID: 25068888 PMCID: PMC4149329 DOI: 10.1021/am503778t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/14/2014] [Indexed: 05/30/2023]
Abstract
Adapting ways to functionalize polymer materials is becoming increasingly important to their implementation in translational biomedical sciences. By tuning the mechanical, chemical, and biological qualities of these materials, their applications can be broadened, opening the door for more advanced integration into modern medical techniques. Here, we report on a method to integrate chemical functionalizations into discrete, microscale polymer structures, which are used for tissue engineering applications, for in vivo localization, and three-dimensional manipulation. Iron oxide nanoparticles were incorporated into the polymer matrix using common photolithographic techniques to create stably functional microstructures with magnetic potential. Using magnetic resonance imaging (MRI), we can promote visualization of microstructures contained in small collections, as well as facilitate the manipulation and alignment of microtopographical cues in a realistic tissue environment. Using similar polymer functionalization techniques, fluorine-containing compounds were also embedded in the polymer matrix of photolithographically fabricated microstructures. The incorporation of fluorine-containing compounds enabled highly sensitive and specific detection of microstructures in physiologic settings using fluorine MRI techniques ((19)F MRI). These functionalization strategies will facilitate more reliable noninvasive tracking and characterization of microstructured polymer implants as well as have implications for remote microstructural scaffolding alignment for three-dimensional tissue engineering applications.
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Affiliation(s)
- James R. Pinney
- Bioengineering and Therapeutic Sciences, University of California, San Francisco, 1700 Fourth Street, Byers Hall Room 203, San Francisco, California 94158, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, 1700 Fourth Street, Byers Hall
Room 216, San Francisco, California 94158, United States
| | - Gerd Melkus
- Department
of Radiology, UCSF Imaging Center at China Basin, University of California, San Francisco, 185 Berry Street, Suite 190, Lobby 6, San Francisco, California 94107, United States
- Department
of Medical Imaging, Ottawa Hospital, 1053 Carling Avenue, Ottawa K1Y 4E9, Ontario, Canada
| | - Alec Cerchiari
- Bioengineering and Therapeutic Sciences, University of California, San Francisco, 1700 Fourth Street, Byers Hall Room 203, San Francisco, California 94158, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, 1700 Fourth Street, Byers Hall
Room 216, San Francisco, California 94158, United States
| | - James Hawkins
- Department
of Radiology, UCSF Imaging Center at China Basin, University of California, San Francisco, 185 Berry Street, Suite 190, Lobby 6, San Francisco, California 94107, United States
| | - Tejal A. Desai
- Bioengineering and Therapeutic Sciences, University of California, San Francisco, 1700 Fourth Street, Byers Hall Room 203, San Francisco, California 94158, United States
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82
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Uskoković V, Desai TA. Does translational symmetry matter on the micro scale? Fibroblastic and osteoblastic interactions with the topographically distinct poly(ε-caprolactone)/hydroxyapatite thin films. ACS Appl Mater Interfaces 2014; 6:13209-20. [PMID: 25014232 PMCID: PMC4134142 DOI: 10.1021/am503043t] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/11/2014] [Indexed: 05/23/2023]
Abstract
Material composition and topography of the cell-contacting material interface are important considerations in the design of biomaterials at the nano and micro scales. This study is one of the first to have assessed the osteoblastic response to micropatterned polymer-ceramic composite surfaces. In particular, the effect of topographic variations of composite poly(ε-caprolactone)/hydroxyapatite (PCL/HAp) films on viability, proliferation, migration and osteogenesis of fibroblastic and osteoblastic MC3T3-E1 cells was evaluated. To that end, three different micropatterned PCL/HAp films were compared: flat and textured, the latter of which included films comprising periodically arranged and randomly distributed oval topographic features 10 μm in diameter, 20 μm in separation and 10 μm in height, comparable to the dimensions of MC3T3-E1 cells. PCL/HAp films were fabricated by the combination of a bottom-up, soft chemical synthesis of the ceramic, nanoparticulate phase and a top-down, photolithographic technique for imprinting fine, microscale features on them. X-ray diffraction analysis indicated an isotropic orientation of both the polymeric chains and HAp crystallites in the composite samples. Biocompatibility tests indicated no significant decrease in their viability when grown on PCL/HAp films. Fibroblast proliferation and migration onto PCL/HAp films proceeded slower than on the control borosilicate glass, with the flat composite film fostering more cell migration activity than the films containing topographic features. The gene expression of seven analyzed osteogenic markers, including procollagen type I, osteocalcin, osteopontin, alkaline phosphatase, and the transcription factors Runx2 and TGFβ-1, was, however, consistently upregulated in cells grown on PCL/HAp films comprising periodically ordered topographic features, suggesting that the higher levels of symmetry of the topographic ordering impose a moderate mechanochemical stress on the adherent cells and thus promote a more favorable osteogenic response. The obtained results suggest that topography can be a more important determinant of the cell/surface interaction than the surface chemistry and/or stiffness as well as that the regularity of the distribution of topographic features can be a more important variable than the topographic features per se.
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Affiliation(s)
- Vuk Uskoković
- Therapeutic Micro and
Nanotechnology Laboratory, Department of Bioengineering
and Therapeutic Sciences, University of
California, San Francisco, San
Francisco, California 94158-2330, United States
- Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, University
of Illinois, Chicago, Illinois 60607-7052, United States
| | - Tejal A. Desai
- Therapeutic Micro and
Nanotechnology Laboratory, Department of Bioengineering
and Therapeutic Sciences, University of
California, San Francisco, San
Francisco, California 94158-2330, United States
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83
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Abstract
Large molecular weight drug delivery to the posterior eye is challenging due to cellular barriers that hinder drug transport. Understanding how to enhance transport across the retinal barrier is important for the design of new drug delivery systems. A novel mechanism to enhance drug transport is the use of geometric properties, which has not been extensively explored in the retina. Planar SU-8/Poly(ethyleneglycol)dimethacrylate microdevices were constructed using photolithography to deliver FITC dextran across an in vitro retinal model. The model consists of retinal pigment epithelial (RPE) cells grown to confluence on transwell inserts, which provides an environment to investigate the influence of geometry on paracellular and transcellular delivery of encapsulated large molecules. Planar microdevices enhanced transport of large molecular weight dextrans across different models of RPE in a size dependent fashion. Increased drug permeation across the RPE was observed with the addition of microdevices as compared to a traditional bolus of FITC dextran. This phenomena was initiated by a non-toxic interaction between the microdevices and the retinal tight junction proteins. Suggesting that increased drug transport occurs via a paracellular pathway. These experiments provide evidence to support the future use of planar unidirectional microdevices for delivery of biologics in ocular applications.
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Affiliation(s)
- Jennifer S. Wade
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, USA
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, USA
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84
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Pinney JR, Du KT, Ayala P, Fang Q, Sievers RE, Chew P, Delrosario L, Lee RJ, Desai TA. Discrete microstructural cues for the attenuation of fibrosis following myocardial infarction. Biomaterials 2014; 35:8820-8828. [PMID: 25047625 DOI: 10.1016/j.biomaterials.2014.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 07/02/2014] [Indexed: 01/14/2023]
Abstract
Chronic fibrosis caused by acute myocardial infarction (MI) leads to increased morbidity and mortality due to cardiac dysfunction. We have developed a therapeutic materials strategy that aims to mitigate myocardial fibrosis by utilizing injectable polymeric microstructures to mechanically alter the microenvironment. Polymeric microstructures were fabricated using photolithographic techniques and studied in a three-dimensional culture model of the fibrotic environment and by direct injection into the infarct zone of adult rats. Here, we show dose-dependent down-regulation of expression of genes associated with the mechanical fibrotic response in the presence of microstructures. Injection of this microstructured material into the infarct zone decreased levels of collagen and TGF-β, increased elastin deposition and vascularization in the infarcted region, and improved functional outcomes after six weeks. Our results demonstrate the efficacy of these discrete anti-fibrotic microstructures and suggest a potential therapeutic materials approach for combatting pathologic fibrosis.
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Affiliation(s)
- James R Pinney
- UC Berkeley - UCSF Graduate Group in Bioengineering, 1700 4th Street, QB3 Byers Hall, Room 203, San Francisco, CA 94158, USA; UCSF Medical Scientist Training Program, 1700 4th Street, QB3 Byers Hall, Room 203, San Francisco, CA 94158, USA
| | - Kim T Du
- UCSF Department of Medicine, Cardiovascular Research Institute and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Box 1354, 513 Parnassus Ave, MS Room 1136, San Francisco, CA 94143, USA
| | - Perla Ayala
- UC Berkeley - UCSF Graduate Group in Bioengineering, 1700 4th Street, QB3 Byers Hall, Room 203, San Francisco, CA 94158, USA; Beth Israel Deaconess Medical Center, Department of Surgery, Center for Life Science Surgery/BIDMC, 11th Floor, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Qizhi Fang
- UCSF Department of Medicine, Cardiovascular Research Institute and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Box 1354, 513 Parnassus Ave, MS Room 1136, San Francisco, CA 94143, USA
| | - Richard E Sievers
- UCSF Department of Medicine, Cardiovascular Research Institute and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Box 1354, 513 Parnassus Ave, MS Room 1136, San Francisco, CA 94143, USA
| | - Patrick Chew
- UCSF Bioengineering and Therapeutic Sciences, 1700 4th Street, Byers Hall Room 203, San Francisco, CA 94158, USA
| | - Lawrence Delrosario
- UCSF School of Medicine, 513 Parnassus Ave, MS Room 1136, San Francisco, CA 94143, USA
| | - Randall J Lee
- UC Berkeley - UCSF Graduate Group in Bioengineering, 1700 4th Street, QB3 Byers Hall, Room 203, San Francisco, CA 94158, USA; UCSF Department of Medicine, Cardiovascular Research Institute and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Box 1354, 513 Parnassus Ave, MS Room 1136, San Francisco, CA 94143, USA
| | - Tejal A Desai
- UC Berkeley - UCSF Graduate Group in Bioengineering, 1700 4th Street, QB3 Byers Hall, Room 203, San Francisco, CA 94158, USA; UCSF Bioengineering and Therapeutic Sciences, 1700 4th Street, Byers Hall Room 203, San Francisco, CA 94158, USA.
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85
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Nyitray CE, Chavez MG, Desai TA. Compliant 3D microenvironment improves β-cell cluster insulin expression through mechanosensing and β-catenin signaling. Tissue Eng Part A 2014; 20:1888-95. [PMID: 24433489 DOI: 10.1089/ten.tea.2013.0692] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Type 1 diabetes is chronic disease with numerous complications and currently no cure. Tissue engineering strategies have shown promise in providing a therapeutic solution, but maintenance of islet function and survival within these therapies represents a formidable challenge. The islet microenvironment may hold the key for proper islet maintenance. To elucidate the microenvironmental conditions necessary for improved islet function and survival, three-dimensional (3D) polyacrylamide cell scaffolds were fabricated with stiffnesses of 0.1 and 10 kPa to regulate the spatial and mechanical control of biosignals. Specifically, we show a significant increase in insulin mRNA expression of 3D primary mouse islet-derived and Min6-derived β-cell clusters grown on compliant 0.1 kPa scaffolds. Moreover, these compliant 0.1 kPa scaffolds also increase glucose sensitivity in Min6-derived β-cell clusters as demonstrated by the increased glucose stimulation index. Our data suggest that stiffness-specific insulin processing is regulated through the myosin light chain kinase (MLCK) and Rho-associated protein kinase (ROCK) mechanosensing pathways. Additionally, β-catenin is required for regulation of stiffness-dependent insulin expression. Through activation or inhibition of β-catenin signaling, reversible control of insulin expression is achieved on the compliant 0.1 kPa and overly stiff 10 kPa substrates. Understanding the role of the microenvironment on islet function can enhance the therapeutic approaches necessary to treat diabetes for improving insulin sensitivity and response.
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Affiliation(s)
- Crystal E Nyitray
- 1 Program in Chemistry & Chemical Biology, University of California , San Francisco, San Francisco, California
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86
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Uskoković V, Desai TA. Simultaneous bactericidal and osteogenic effect of nanoparticulate calcium phosphate powders loaded with clindamycin on osteoblasts infected with Staphylococcus aureus. Mater Sci Eng C Mater Biol Appl 2014; 37:210-22. [PMID: 24582242 DOI: 10.1016/j.msec.2014.01.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/05/2013] [Accepted: 01/05/2014] [Indexed: 01/06/2023]
Abstract
Staphylococcus aureus internalized by bone cells and shielded from the immune system provides a reservoir of bacteria in recurring osteomyelitis. Its targeting by the antibiotic therapy may thus be more relevant for treating chronic bone infection than eliminating only the pathogens colonizing the bone matrix. Assessed was the combined osteogenic and antibacterial effect of clindamycin-loaded calcium phosphate nanoparticles of different monophasic compositions on co-cultures comprising osteoblasts infected with S. aureus. Antibiotic-carrying particles were internalized by osteoblasts and minimized the concentration of intracellular bacteria. In vitro treatments of the infected cells, however, could not prevent cell necrosis due to the formation of toxic byproducts of the degradation of the bacterium. Antibiotic-loaded particles had a positive morphological effect on osteoblasts per se, without reducing their viability, alongside stimulating the upregulation of expression of different bone growth markers in infected osteoblasts to a higher degree than achieved during the treatment with antibiotic only.
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Affiliation(s)
- Vuk Uskoković
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA; Department of Bioengineering, University of Illinois, Chicago, USA.
| | - Tejal A Desai
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
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87
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Abstract
Transplantation of islet or beta cells is seen as the cure for type 1 diabetes since it allows physiological regulation of blood glucose levels without requiring any compliance from the patients. In order to circumvent the use of immunosuppressive drugs (and their side effects), semipermeable membranes have been developed to encapsulate and immunoprotect transplanted cells. This review presents the historical developments of immunoisolation and provides an update on the current research in this field. A particular emphasis is laid on the fabrication, characterization and performance of membranes developed for immunoisolation applications.
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Affiliation(s)
- Julien Schweicher
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco (UCSF), 1700 4 Street, Box 2520, San Francisco, CA, 94158, USA
| | - Crystal Nyitray
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco (UCSF), 1700 4 Street, Box 2520, San Francisco, CA, 94158, USA
| | - Tejal A. Desai
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco (UCSF), 1700 4 Street, Box 2520, San Francisco, CA, 94158, USA
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Uskoković V, Desai TA. In vitro analysis of nanoparticulate hydroxyapatite/chitosan composites as potential drug delivery platforms for the sustained release of antibiotics in the treatment of osteomyelitis. J Pharm Sci 2013; 103:567-79. [PMID: 24382825 DOI: 10.1002/jps.23824] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/06/2013] [Accepted: 12/03/2013] [Indexed: 12/17/2022]
Abstract
Nanoparticulate composites of hydroxyapatite (HAp) and chitosan were synthesized by ultrasound-assisted sequential precipitation and characterized for their microstructure at the atomic scale, surface charge, drug release properties, and combined antibacterial and osteogenic response. Crystallinity of HAp nanoparticles was reduced because of the interference of the surface layers of chitosan with the dissolution/reprecipitation-mediated recrystallization mechanism that conditions the transition from the as-precipitated amorphous calcium phosphate phase to the most thermodynamically stable one--HAp. Embedment of 5-10 nm sized, narrowly dispersed HAp nanoparticles within the polymeric matrix mitigated the burst release of the small molecule model drug, fluorescein, bound to HAp by physisorption, and promoted sustained-release kinetics throughout the 3 weeks of release time. The addition of chitosan to the particulate drug carrier formulation, however, reduced the antibacterial efficacy against S aureus. Excellent cell spreading and proliferation of osteoblastic MC3T3-E1 cells evidenced on microscopic conglomerates of HAp nanoparticles in vitro also markedly diminished on HAp/chitosan composites. Mitochondrial dehydrogenase activity exhibited normal values only for HAp/chitosan particle concentrations of up to 2 mg/cm(2) and significantly dropped, by about 50%, at higher particle concentrations (4 and 8 mg/cm(2)). The gene expression of osteocalcin, a mineralization inductor, and the transcription factor Runx2 was downregulated in cells incubated in the presence of 3 mg/cm(2) HAp/chitosan composite particles, whereas the expression of osteopontin, a potent mineralization inhibitor, was upregulated, further demonstrating the partially unfavorable osteoblastic cell response to the given particles. The peak in the expression of osteogenic markers paralleling the osteoblastic differentiation was also delayed most for the cell population incubated with HAp/chitosan particles. Overall, the positive effect of chitosan coating on the drug elution profile of HAp nanoparticles as carriers for the controlled delivery of antibiotics in the treatment of osteomyelitis was compensated for by the lower bacteriostatic efficiency and the comparatively unviable cell response to the composite material, especially at higher dosages.
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Affiliation(s)
- Vuk Uskoković
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, 94158-2330
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89
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Kam KR, Walsh LA, Bock SM, Ollerenshaw JD, Ross RF, Desai TA. The effect of nanotopography on modulating protein adsorption and the fibrotic response. Tissue Eng Part A 2013; 20:130-8. [PMID: 23914986 DOI: 10.1089/ten.tea.2012.0772] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding and modulating the cellular response to implanted biomaterials is crucial for the field of tissue engineering and regenerative medicine. Since cells typically reside in an extracellular matrix containing nanoscale architecture, identifying synthetic nanostructures that induce desirable cellular behaviors could greatly impact the field. Using nanoimprint lithography, nanostructured patterns were generated on thin film polymeric materials. The ability of these surfaces to influence protein adsorption, fibroblast proliferation and morphology, and fibrotic markers was investigated. Nanostructured features with aspect ratios greater than five allowed for less protein adsorption, resulting in decreased fibroblast proliferation and rounded cellular morphology. These nanofeatures also induced significantly lower gene expression of collagen 1α2, collagen 3α1, and growth factors such as connective tissue growth factor, integrin linked kinase, transforming growth factor β1 (TGF-β1), and epidermal growth factor, key factors associated with a fibrotic response. The results demonstrate that select nanostructured surfaces could be used to modulate the fibrotic behavior in cells and have the potential to be used as antifibrotic architecture for medical implants or tissue engineering scaffolds.
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Affiliation(s)
- Kimberly R Kam
- 1 University of California Berkeley and University of California San Francisco Graduate Program in Bioengineering , San Francisco, California
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90
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Uskoković V, Hoover C, Vukomanović M, Uskoković DP, Desai TA. Osteogenic and antimicrobial nanoparticulate calcium phosphate and poly-(D,L-lactide-co-glycolide) powders for the treatment of osteomyelitis. Mater Sci Eng C Mater Biol Appl 2013; 33:3362-73. [PMID: 23706222 PMCID: PMC3672472 DOI: 10.1016/j.msec.2013.04.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/31/2013] [Accepted: 04/08/2013] [Indexed: 01/31/2023]
Abstract
Development of a material for simultaneous sustained and localized delivery of antibiotics and induction of spontaneous regeneration of hard tissues affected by osteomyelitis stands for an important clinical need. In this work, a comparative analysis of the bacterial and osteoblastic cell response to two different nanoparticulate carriers of clindamycin, an antibiotic commonly prescribed in the treatment of bone infection, one composed of calcium phosphate and the other comprising poly-(D,L-lactide-co-glycolide)-coated calcium phosphate, was carried out. Three different non-cytotoxic phases of calcium phosphate, exhibiting dissolution and drug release profiles in the range of one week to two months to one year, respectively, were included in the analysis: monetite, amorphous calcium phosphate and hydroxyapatite. Spherical morphologies and narrow size distribution of both types of nanopowders were confirmed in transmission and scanning electron microscopic analyses. The antibiotic-containing powders exhibited sustained drug release contingent upon the degradation rate of the carrier. Assessment of the antibacterial performance of the antibiotic-encapsulated powders against Staphylococcus aureus, the most common pathogen isolated from infected bone, yielded satisfactory results both in broths and on blood agar plates for all the analyzed powders. In contrast, no cytotoxic behavior was detected upon the incubation of the antibiotic powders with the osteoblastic MC3T3-E1 cell line for up to three weeks. The cells were shown to engage in a close contact with the antibiotic-containing particles, irrespective of their internal or surface phase composition, polymeric or mineral. At the same time, both types of particles upregulated the expression of osteogenic markers osteocalcin, osteopontin, Runx2 and protocollagen type I, suggesting their ability to promote osteogenesis and enhance remineralization of the infected site in addition to eliminating the bacterial source of infection.
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Affiliation(s)
- Vuk Uskoković
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA.
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91
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Uskoković V, Batarni SS, Schweicher J, King A, Desai TA. Effect of calcium phosphate particle shape and size on their antibacterial and osteogenic activity in the delivery of antibiotics in vitro. ACS Appl Mater Interfaces 2013; 5:2422-31. [PMID: 23484624 PMCID: PMC3647690 DOI: 10.1021/am4000694] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Powders composed of four morphologically different calcium phosphate particles were prepared by precipitation from aqueous solutions: flaky, brick-like, elongated orthogonal, and spherical. The particles were then loaded with either clindamycin phosphate as the antibiotic of choice or fluorescein, a model molecule used to assess the drug release properties. A comparison was carried out of the effect of such antibiotic-releasing materials on: sustained drug release profiles; Staphylococcus aureus growth inhibition; and osteogenic propensities in vitro. Raman spectroscopic analysis indicated the presence of various calcium phosphate phases, including monetite (flaky and elongated orthogonal particles), octacalcium phosphate (brick-shaped particles), and hydroxyapatite (spherical particles). Testing the antibiotic-loaded calcium phosphate powders for bacterial growth inhibition demonstrated satisfying antibacterial properties both in broths and on agar plates. All four calcium-phosphate-fluorescein powders exhibited sustained drug release over 21 days. The calcium phosphate sample with the highest specific surface area and the smallest, spherical particle size was the most effective in both drug loading and release, consequently having the highest antibacterial efficiency. Moreover, the highest cell viability, the largest gene expression upregulation of three different osteogenic markers--osteocalcin, osteopontin, and Runx2--as well as the least disrupted cell cytoskeleton and cell morphologies were also noticed for the calcium phosphate powder composed of the smallest, spherical nanosized particles. Still, all four powders exerted a viable effect on osteoblastic MC3T3-E1 cells in vitro, as evidenced by both morphological assessments on fluorescently stained cells and measurements of their mitochondrial activity. The obtained results suggest that the nanoscale particle size and the corresponding coarseness of the surface of particle conglomerates as the cell attachment points may present a favorable starting point for the development of calcium-phosphate-based osteogenic drug delivery devices.
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Affiliation(s)
- Vuk Uskoković
- Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158-2330, United States.
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Bernards DA, Bhisitkul RB, Wynn P, Steedman MR, Lee OT, Wong F, Thoongsuwan S, Desai TA. Ocular biocompatibility and structural integrity of micro- and nanostructured poly(caprolactone) films. J Ocul Pharmacol Ther 2013; 29:249-57. [PMID: 23391326 DOI: 10.1089/jop.2012.0152] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The identification of biomaterials that are well tolerated in the eye is important for the development of new ocular drug delivery devices and implants, and the application of micro- and nanoengineered devices to biomedical treatments is predicated on the long-term preservation within the target organ or tissue of the very small functional design elements. This study assesses the ocular tolerance and durability of micro- and nanostructured biopolymer thin films injected or implanted into the rabbit eye. Structured poly(caprolactone) (PCL) thin films were placed in adult rabbit eyes for survival studies, with serial ophthalmic examinations over 6 months. Morphologic abnormalities and device/tissue reactions were evaluated by histologic studies, and scanning electron microscopy (SEM) of films was used to determine the structural integrity. Structured PCL thin films (20- to 40-μm thick) were constructed to design specifications with 50-μm linear microgrooves or arrays of nanopores with ~30-nm diameters. After up to 9 months of ocular residency, SEM on devices retrieved from the eye showed preservation of micro- and nanostructural features. In ocular safety evaluations carried out over 6 months, serial examinations in 18 implanted eyes showed no evidence of chronic inflammation, cataractogenesis, or retinal toxicity. Postoperative ocular inflammation was seen in 67% of eyes for 1 week, and persistent corneal edema occurred in 1 eye. Histology revealed no ocular inflammation or morphologic abnormalities of ocular tissues. Thin-film/tissue responses such as cellular reaction, fibrosis, or surface biodeposits were not seen. Micro- and nanostructured PCL thin films exhibited acceptable ocular tolerance and maintained the structural integrity of design features while residing in the eye. Thin-film micro- and nanostructured PCL appears to be a feasible biomaterial for intraocular therapeutic applications.
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Affiliation(s)
- Daniel A Bernards
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
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93
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Silvestrini MT, Yin D, Coppes VG, Mann P, Martin AJ, Larson PS, Starr PA, Gupta N, Panter SS, Desai TA, Lim DA. Radially branched deployment for more efficient cell transplantation at the scale of the human brain. Stereotact Funct Neurosurg 2013; 91:92-103. [PMID: 23343609 DOI: 10.1159/000343213] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/27/2012] [Indexed: 01/15/2023]
Abstract
BACKGROUND In preclinical studies, cell transplantation into the brain has shown great promise for the treatment of a wide range of neurological diseases. However, the use of a straight cannula and syringe for cell delivery to the human brain does not approximate cell distribution achieved in animal studies. This technical deficiency may limit the successful clinical translation of cell transplantation. OBJECTIVE To develop a stereotactic device that effectively distributes viable cells to the human brain. Our primary aims were to (1) minimize the number of transcortical penetrations required for transplantation, (2) reduce variability in cell dosing and (3) increase cell survival. METHODS We developed a modular cannula system capable of radially branched deployment (RBD) of a cell delivery catheter at variable angles from the longitudinal device axis. We also developed an integrated catheter-plunger system, eliminating the need for a separate syringe delivery mechanism. The RBD prototype was evaluated in vitro and in vivo with subcortical injections into the swine brain. Performance was compared to a 20G straight cannula with dual side ports, a device used in current clinical trials. RESULTS RBD enabled therapeutic delivery in a precise 'tree-like' pattern branched from a single initial trajectory, thereby facilitating delivery to a volumetrically large target region. RBD could transplant materials in a radial pattern up to 2.0 cm from the initial penetration tract. The novel integrated catheter-plunger system facilitated manual delivery of small and precise volumes of injection (1.36 ± 0.13 µl per cm of plunger travel). Both dilute and highly concentrated neural precursor cell populations tolerated transit through the device with high viability and unaffected developmental potential. While reflux of infusate along the penetration tract was problematic with the use of the 20G cannula, RBD was resistant to this source of cell dose variability in agarose. RBD enabled radial injections to the swine brain when used with a modern clinical stereotactic system. CONCLUSIONS By increasing the total delivery volume through a single transcortical penetration in agarose models, RBD strategy may provide a new approach for cell transplantation to the human brain. Incorporation of RBD or selected aspects of its design into future clinical trials may increase the likelihood of successful translation of cell-based therapy to the human patient.
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Affiliation(s)
- Matthew T Silvestrini
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
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94
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Kam KR, Walsh LA, Bock SM, Koval M, Fischer KE, Ross RF, Desai TA. Nanostructure-mediated transport of biologics across epithelial tissue: enhancing permeability via nanotopography. Nano Lett 2013; 13:164-71. [PMID: 23186530 PMCID: PMC4418930 DOI: 10.1021/nl3037799] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Herein, we demonstrate that nanotopographical cues can be utilized to enable biologics >66 kDa to be transported across epithelial monolayers. When placed in contact with epithelial monolayers, nanostructured thin films loosen the epithelial barrier and allow for significantly increased transport of FITC-albumin, FITC-IgG, and a model therapeutic, etanercept. Our work highlights the potential to use drug delivery systems which incorporate nanotopography to increase the transport of biologics across epithelial tissue.
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Affiliation(s)
- Kimberly R Kam
- UC Berkeley & UCSF Graduate Program in Bioengineering, 1700 4th Street, Building QB3 Room 204, UCSF Mission Bay Campus, San Francisco, California 94158, USA
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Abstract
This highlight article describes current nano- and microfabrication techniques for creating drug delivery devices. We first review the main physiological barriers to delivering therapeutic agents. Then, we describe how novel fabrication methods can be utilized to combine many features into a single physiologically relevant device to overcome drug delivery challenges.
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Affiliation(s)
- Kimberly R Kam
- UC Berkeley and UCSF Joint Graduate Group in Bioengineering, USA
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96
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Abramson S, Ackermann DM, Akins R, Anders R, Andersen PJ, Anderson JM, Ankrum JA, Anseth KS, Antonucci J, Atzet S, Badylak SF, Baura GD, Bellamkonda RV, Best SM, Bhumiratana S, Bianco RW, Bokros JC, Borovetz HS, Boskey AL, Brown JL, Brown BN, Brown SA, Brunski JB, Cahn F, Ritchie AC, Caplan AI, Carpenedo RL, Chilkoti A, Chung S, Cimetta E, Cleary G, Clements IP, Colas A, Coleman KP, Conway DE, Cooper SL, Costerton B, Coury AJ, Cunanan C, Curtis J, D’Amore A, DeMeo P, Desai TA, Dickens S, Domingo G, Duncan E, Eskin SG, Feigal DW, Ferreira L, Fuller J, Gallegos RP, Gawalt E, Ghosh K, Ghosn B, Gilbert TW, Glaser DE, Godier-Furnemont A, Gombotz WR, Grainger DW, Grunkemeier GL, Hacking SA, Hallab NJ, Hall-Stoodley L, Hanson SR, Haubold AD, Hauch KD, Hawkins KR, Heath DE, Helm DL, Hench LL, Hensten A, Hill RT, Hobson C, Hoerstrup SP, Hoffman AS, Horbett TA, Hubbell JA, Humayun MS, Ideker R, Ingber DE, Jain R, Jacob J, Jacobs JJ, Jacobsen N, Jin R, Johnson RJ, Karp JM, Kasper FK, Kathju S, Khademhosseini A, Kim S, King MW, Kleiner LW, Kohn J, Koschwanez HE, Kumbar SG, Kuo CK, LaFleur L, Lahti MT, Lambert B, Langer R, Laurencin CT, Lee-Parritz D, Lemons JE, Levin M, Levy RJ, Lewerenz GM, Li WJ, Lin CC, Liu F, Lowrie WG, Lu Y, Lysaght MJ, Maidhof R, Mansbridge J, Cristina M, Martins L, Martin J, Mayesh JP, McDevitt TC, McIntire LV, Merrit K, Migliaresi C, Mikos AG, Misch CE, Mitchell RN, More RB, Moss CW, Munson JM, Navarro M, Nerem RM, Ogawa R, Orgill BD, Orgill DP, Padera RF, Pandit A, Park K, Patel AS, Peck RB, Peckham PH, Peppas NA, Pereira MN, Planell J, Popat KC, Prestwich GD, Pun SH, Rabolt J, Rainbow RS, Rajab T, Ratner BD, Reichert WM, Rivard AL, Rowley AP, Ruan G, Sacks M, Sarkar D, Schaefer S, Schmidt CE, Schoen FJ, Schutte SC, Sefton MV, Shalaby SW, Shirtliff M, Simon MA, Singh M, Slack SM, Spelman FA, Starr A, Stayton PS, Steinert R, Stoodley P, Suri S, Swi Chang TM, Tandon N, Tanguay AR, Taylor MS, Teo GS, Thodeti CK, Tolkoff J, Treiser M, Tuan RS, Tucker EI, Venugopalan R, Vicari AR, Viney C, Voight JM, Vunjak-Novakovic G, Wagner WR, Wang L, Wasiluk KR, Watts DC, Weigl BH, Weiland JD, Whalen JJ, Williams DF, Williams RL, Wilson JT, Wilson CG, Winter J, Wolf MF, Wright JC, Yager P, Zhao W. Contributors. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00150-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Curtis MW, Budyn E, Desai TA, Samarel AM, Russell B. Microdomain heterogeneity in 3D affects the mechanics of neonatal cardiac myocyte contraction. Biomech Model Mechanobiol 2013; 12:95-109. [PMID: 22407215 PMCID: PMC3407350 DOI: 10.1007/s10237-012-0384-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 02/23/2012] [Indexed: 01/26/2023]
Abstract
Cardiac muscle cells are known to adapt to their physical surroundings, optimizing intracellular organization and contractile function for a given culture environment. A previously developed in vitro model system has shown that the inclusion of discrete microscale domains (or microrods) in three dimensions (3D) can alter long-term growth responses of neonatal ventricular myocytes. The aim of this work was to understand how cellular contact with such a domain affects various mechanical changes involved in cardiac muscle cell remodeling. Myocytes were maintained in 3D gels over 5 days in the presence or absence of 100-μm-long microrods, and the effect of this local heterogeneity on cell behavior was analyzed via several imaging techniques. Microrod abutment resulted in approximately twofold increases in the maximum displacement of spontaneously beating myocytes, as based on confocal microscopy scans of the gel xy-plane or the myocyte long axis. In addition, microrods caused significant increases in the proportion of aligned myofibrils (≤20° deviation from long axis) in fixed myocytes. Microrod-related differences in axial contraction could be abrogated by long-term interruption of certain signals of the RhoA-/Rho-associated kinase (ROCK) or protein kinase C (PKC) pathway. Furthermore, microrod-induced increases in myocyte size and protein content were prevented by ROCK inhibition. In all, the data suggest that microdomain heterogeneity in 3D appears to promote the development of axially aligned contractile machinery in muscle cells, an observation that may have relevance to a number of cardiac tissue engineering interventions.
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Affiliation(s)
- Matthew W. Curtis
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 South Wolcott Avenue, Chicago, IL 60612, USA
| | - Elisa Budyn
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Tejal A. Desai
- Department of Physiology and Division of Bioengineering, University of California at San Francisco, San Francisco, CA, USA
| | - Allen M. Samarel
- The Cardiovascular Institute, Loyola University Medical Center, Maywood, IL, USA
| | - Brenda Russell
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 South Wolcott Avenue, Chicago, IL 60612, USA,
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Chirra HD, Desai TA. Multi-reservoir bioadhesive microdevices for independent rate-controlled delivery of multiple drugs. Small 2012; 8:3839-3846. [PMID: 22962019 PMCID: PMC3527694 DOI: 10.1002/smll.201201367] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/07/2012] [Indexed: 05/29/2023]
Abstract
A variety of oral administrative systems such as enterically coated tablets, capsules, particles, and liposomes have been developed to improve oral bioavailability of drugs. However, they suffer from poor intestinal localization and therapeutic efficacy due to the various physiological conditions and high shear fluid flow. Fabrication of novel microdevices combined with the introduction of controlled release, improved adhesion, selective targeting, and tissue permeation may overcome these issues and potentially diminish the toxicity and high frequency of conventional oral administration. Herein, thin, asymmetric, poly(methyl methacrylate) (PMMA) microdevices are fabricated with multiple reservoirs using photolithography and reactive ion etching. They are loaded with different individual model drug in each reservoir. Enhanced bioadhesion of the microdevices is observed in the presence of a conjugated of targeting protein (tomato lectin) to the PMMA surface. As compared to drug encompassing hydrogels, an increase in drug permeation across the caco-2 monolayer is noticed in the presence of a microdevice loaded with the same drug-hydrogel system. Also, the release of multiple drugs from their respective reservoirs is found to be independent from each other. The use of different hydrogel systems in each reservoir shows differences in the controlled release of the respective drugs over the same release period. These results suggest that, in the future, microfabricated unidirectional multi-drug releasing devices will have an impact on the oral administration of a broad range of therapeutics.
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Affiliation(s)
| | - Tejal A. Desai
- Corresponding Author. 1700 4 Street, Byers Hall 204, Box 2520, San Francisco, CA 94158, USA. Tel.: +1 415 514 4503; fax: +1 415 514 9656.
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Mendelsohn AD, Nyitray C, Sena M, Desai TA. Size-controlled insulin-secreting cell clusters. Acta Biomater 2012; 8:4278-84. [PMID: 22902301 DOI: 10.1016/j.actbio.2012.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 08/03/2012] [Accepted: 08/08/2012] [Indexed: 10/28/2022]
Abstract
The search for an effective cure for type I diabetes from the transplantation of encapsulated pancreatic β-cell clusters has so far produced sub-optimal clinical outcomes. Previous efforts have not controlled the size of transplanted clusters, a parameter implicated in affecting long-term viability and the secretion of therapeutically sufficient insulin. Here we demonstrate a method based on covalent attachment of patterned laminin for fabricating uniformly size-controlled insulin-secreting cell clusters. We show that cluster size within the range 40-120μm in diameter affects a variety of therapeutically relevant cellular responses including insulin expression, content and secretion. Our studies elucidate two size-dependent phenomena: (1) as the cluster size increases from 40μm to 60μm, glucose stimulation results in a greater amount of insulin produced per cell; and (2) as the cluster size increases beyond 60μm, sustained glucose stimulation results in a greater amount of insulin secreted per cell. Our study describes a method for producing uniformly sized insulin-secreting cell clusters, and since larger cluster sizes risk nutrient availability limitations, our data suggest that 100-120μm clusters may provide optimal viability and efficacy for encapsulated β-cell transplants as a treatment for type I diabetes and that further in vivo evaluation is warranted.
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100
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Chirra HD, Desai TA. Emerging microtechnologies for the development of oral drug delivery devices. Adv Drug Deliv Rev 2012; 64:1569-78. [PMID: 22981755 PMCID: PMC3488155 DOI: 10.1016/j.addr.2012.08.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 08/06/2012] [Accepted: 08/12/2012] [Indexed: 10/27/2022]
Abstract
The development of oral drug delivery platforms for administering therapeutics in a safe and effective manner across the gastrointestinal epithelium is of much importance. A variety of delivery systems such as enterically coated tablets, capsules, particles, and liposomes have been developed to improve oral bioavailability of drugs. However, orally administered drugs suffer from poor localization and therapeutic efficacy due to various physiological conditions such as low pH, and high shear intestinal fluid flow. Novel platforms combining controlled release, improved adhesion, tissue penetration, and selective intestinal targeting may overcome these issues and potentially diminish the toxicity and high frequency of administration associated with conventional oral delivery. Microfabrication along with appropriate surface chemistry, provide a means to fabricate these platforms en masse with flexibility in tailoring the shape, size, reservoir volume, and surface characteristics of microdevices. Moreover, the same technology can be used to include integrated circuit technology and sensors for designing sophisticated autonomous drug delivery devices that promise to significantly improve point of care diagnostic and therapeutic medical applications. This review sheds light on some of the fabrication techniques and addresses a few of the microfabricated devices that can be effectively used for controlled oral drug delivery applications.
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Affiliation(s)
- Hariharasudhan D. Chirra
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, U.S.A
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, U.S.A
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