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Chendke GS, Faleo G, Juang C, Parent AV, Bernards DA, Hebrok M, Tang Q, Desai TA. Supporting Survival of Transplanted Stem-Cell-Derived Insulin-Producing Cells in an Encapsulation Device Augmented with Controlled Release of Amino Acids. ACTA ACUST UNITED AC 2019; 3. [PMID: 31633004 DOI: 10.1002/adbi.201900086] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Pancreatic islet transplantation is a promising treatment for type I diabetes, which is a chronic autoimmune disease in which the host immune cells attack insulin-producing beta cells. The impact of this therapy is limited due to tissue availability and dependence on immunosuppressive drugs that prevent immune rejection of the transplanted cells. These issues can be solved by encapsulating stem cell-derived insulin-producing cells in an immunoprotective device. However, encapsulation exacerbates ischemia, and the lack of vasculature at the implantation site post-transplantation worsens graft survival. Here, an encapsulation device that supplements nutrients to the cells is developed to improve the survival of encapsulated stem cell-derived insulin-producing cells in the poorly vascularized subcutaneous space. An internal compartment in the device is fabricated to provide zero-order release of alanine and glutamine for several weeks. The amino acid reservoir sustains viability of insulin-producing cells in nutrient limiting conditions in vitro. Moreover, the reservoir also increases cell survival by 30% after transplanting the graft in the subcutaneous space.
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Affiliation(s)
- Gauree S Chendke
- Department of Bioengineering and Therapeutic Sciences, University of California, 1700 4th Street, Byers Hall, Box 2520, San Francisco, CA 94158, USA
| | - Gaetano Faleo
- Department of Surgery, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Charity Juang
- UCSF Diabetes Center, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Audrey V Parent
- UCSF Diabetes Center, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Daniel A Bernards
- Department of Bioengineering and Therapeutic Sciences, University of California, 1700 4th Street, Byers Hall, Box 2520, San Francisco, CA 94158, USA
| | - Matthias Hebrok
- UCSF Diabetes Center, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Qizhi Tang
- Department of Surgery, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, 1700 4th Street, Byers Hall, Box 2520, San Francisco, CA 94158, USA
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Devadasu VR, Alshammari TM, Aljofan M. Current advances in the utilization of nanotechnology for the diagnosis and treatment of diabetes. Int J Diabetes Dev Ctries 2017. [DOI: 10.1007/s13410-017-0558-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Abstract
INTRODUCTION Proteins are effective biotherapeutics with applications in diverse ailments. Despite being specific and potent, their full clinical potential has not yet been realized. This can be attributed to short half-lives, complex structures, poor in vivo stability, low permeability, frequent parenteral administrations and poor adherence to treatment in chronic diseases. A sustained release system, providing controlled release of proteins, may overcome many of these limitations. AREAS COVERED This review focuses on recent development in approaches, especially polymer-based formulations, which can provide therapeutic levels of proteins over extended periods. Advances in particulate, gel-based formulations and novel approaches for extended protein delivery are discussed. Emphasis is placed on dosage form, method of preparation, mechanism of release and stability of biotherapeutics. EXPERT OPINION Substantial advancements have been made in the field of extended protein delivery via various polymer-based formulations over last decade despite the unique delivery-related challenges posed by protein biologics. A number of injectable sustained-release formulations have reached market. However, therapeutic application of proteins is still hampered by delivery-related issues. A large number of protein molecules are under clinical trials, and hence, there is an urgent need to develop new methods to deliver these highly potent biologics.
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Affiliation(s)
- Ravi Vaishya
- University of Missouri-Kansas City, Pharmaceutical Sciences , Kansas City, MO , USA
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Cho S, Lee S, Jeong SH, Kim Y, Kim SC, Hwang W, Park J. Anodic aluminium oxide membranes for immunoisolation with sufficient oxygen supply for pancreatic islets. Integr Biol (Camb) 2013; 5:828-34. [PMID: 23546334 DOI: 10.1039/c3ib20226g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Immunoisolation membranes have been developed for various cell encapsulations for therapeutic purposes. However effective encapsulation systems have been hindered by low oxygen (O2) permeability or imperfect immunoisolation caused by either low porosity or non-uniform pore geometry. Here, we report an encapsulation method that uses an anodic aluminum oxide membrane formed by polyethylene oxide self-assembly to obtain nanochannels with both high selectivity in excluding immune molecules and high permeability of nutrients such as glucose, insulin, and O2. The extracorporeal encapsulation system composed of these membranes allows O2 flux to meet the O2 demand of pancreatic islets of Langerhans and provides excellent in vitro viability and functionality of islets.
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Affiliation(s)
- Siwoo Cho
- Dept. Mechanical Engineering POSTECH, San 31, Hyoja-dong, Nam-gu, Pohang, Gyoengbuk, Republic of Korea
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Aw MS, Addai-Mensah J, Losic D. Polymer Micelles for Delayed Release of Therapeutics from Drug-Releasing Surfaces with Nanotubular Structures. Macromol Biosci 2012; 12:1048-52. [DOI: 10.1002/mabi.201200012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 02/17/2012] [Indexed: 01/16/2023]
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Aw MS, Addai-Mensah J, Losic D. A multi-drug delivery system with sequential release using titania nanotube arrays. Chem Commun (Camb) 2012; 48:3348-50. [DOI: 10.1039/c2cc17690d] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Catalano PN, Bourguignon NS, Alvarez GS, Libertun C, Diaz LE, Desimone MF, Lux-Lantos V. Sol–gel immobilized ovarian follicles: collaboration between two different cell types in hormone production and secretion. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm30888f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Aw MS, Addai-Mensah J, Losic D. Magnetic-responsive delivery of drug-carriers using titania nanotube arrays. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm16819g] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gálvez P, Ruiz A, Clares B. El futuro de la medicina clínica hacia nuevas terapias: terapia celular, génica y nanomedicina. Med Clin (Barc) 2011; 137:645-9. [DOI: 10.1016/j.medcli.2010.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 12/03/2010] [Accepted: 12/14/2010] [Indexed: 01/06/2023]
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Ruder WC, Leduc PR. Bioinspirations: cell-inspired small-scale systems for enabling studies in experimental biomechanics. Integr Comp Biol 2011; 51:133-41. [PMID: 21705801 DOI: 10.1093/icb/icr010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Biomechanical forces govern the behaviors of organisms and their environment and examining these behaviors to understand the underlying phenomena is an important challenge. One experimental approach for probing these interactions between organisms and their biomechanical environment uses biologically-inspired, artificial surrogates that reproduce organic mechanical systems. For the case of complex, multicellular organisms, robot surrogates have been particularly effective, such as in the analysis of the fins of fish and insects' wings. This biologically-inspired approach is also exciting when examining cell-scale responses as multicellular organisms' behavior is directly influenced by the integrated interactions of smaller-scale components (i.e., cells). In this review, we introduce the burgeoning field of engineering of artificial cells, which focuses on developing cell-scale entities replicating cellular behaviors. We describe both a bottom-up approach to constructing artificial cells, using molecular components to directly assemble artificial cells, as well as a top-down approach, in which living cells are encapsulated in a single entity whose behavior is determined by its constituent members. In particular, we discuss the potential role of these artificial cells as implantable controllers, designed to alter the mechanical behavior of a host organism. Eventually, artificial cells designed to function as small-scale controllers may help alter organisms' phenotypes.
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Affiliation(s)
- Warren C Ruder
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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Lee S, Park M, Park HS, Kim Y, Cho S, Cho JH, Park J, Hwang W. A polyethylene oxide-functionalized self-organized alumina nanochannel array for an immunoprotection biofilter. LAB ON A CHIP 2011; 11:1049-53. [PMID: 21283907 DOI: 10.1039/c0lc00499e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nanochannel membranes have been fabricated for many biological and engineering applications. However, due to low-throughput process, high cost, unsuitable pore geometries, and low chemical/mechanical stability, we could not have obtained optimized nanochannel membranes for biomedical treatments as well as a novel building block for artificial cell membranes. Here, we report a PEO-functionalized straight nanochannel array based on a self-organized porous alumina for a novel biofilter with antifouling, superior immunoprotection and high permeability of nutrients, which have excellent in vivo mechanical stability. Thus, our strategy may provide great advantages in novel membrane biotechnologies such as biofiltration, artificial cells, and drug delivery.
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Affiliation(s)
- Sangmin Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, South Korea
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Yamazoe H, Keino-Masu K, Masu M. Combining the cell-encapsulation technique and axon guidance for cell transplantation therapy. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2010; 21:1815-26. [PMID: 20557690 DOI: 10.1163/092050609x12567186470615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In cell transplantation therapy for the treatment of neurodegenerative disorders, encapsulation of implanted cells in a semipermeable membrane is a promising approach to protect the implanted cells from host immune rejection and inhibit the invasion of tumor into surrounding tissue if the implanted cells form a tumor after transplantation. However, implanted neurons isolated by capsules could not build connections with host neurons, preventing the implanted neurons from responding to stimuli from host neurons. In the present study, we focused on the passage of neurites and axons navigated by axon guidance molecules through membrane pores to enable encapsulated neurons and host neurons to form connections. The type of matrix coated on membranes and the pore size of the membranes greatly affected the successful passage of PC12 neurites through membrane pores. PC12 neurites preferably passed through collagen-coated membranes with pores greater than 0.8 μm in diameter, but the neurites did not pass through albumin- or fibronectin-coated membranes or membranes with pores less than 0.1 μm in diameter. We could navigate the direction of commissural neural axon extensions by utilizing the axon guidance molecules secreted from floor plate and make guided axons pass through the membrane pores. These results suggest the feasibility of building connections between encapsulated neurons and host neurons by encapsulating the implanted neurons and axon guidance molecules, which attract the axons of host neurons into the capsule, in the porous membranes with suitable pore size and matrix coating.
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Affiliation(s)
- Hironori Yamazoe
- Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
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13
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Santos E, Zarate J, Orive G, Hernández RM, Pedraz JL. Biomaterials in Cell Microencapsulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 670:5-21. [DOI: 10.1007/978-1-4419-5786-3_2] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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de Vos P, Spasojevic M, Faas MM. Treatment of diabetes with encapsulated islets. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 670:38-53. [PMID: 20384217 DOI: 10.1007/978-1-4419-5786-3_5] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Cell encapsulation has been proposed for the treatment of a wide variety of diseases since it allows for transplantation of cells in the absence of undesired immunosuppression. The technology has been proposed to be a solution for the treatment of diabetes since it potentially allows a mandatory minute-to-minute regulation of glucose levels without side-effects. Encapsulation is based on the principle that transplanted tissue is protected for the host immune system by a semipermeable capsule. Many different concepts of capsules have been tested. During the past two decades three major approaches of encapsulation have been studied. These include (i) intravascular macrocapsules, which are anastomosed to the vascular system as AV shunt, (ii) extravascular macrocapsules, which are mostly diffusion chambers transplanted at different sites and (iii) extravascular microcapsules transplanted in the peritoneal cavity. The advantages and pitfalls of the three approaches are discussed and compared in view of applicability in clinical islet transplantation.
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Affiliation(s)
- Paul de Vos
- Department of Pathology and Laboratory Medicine, Section of Immunoendocrinology, University of Groningen. Hanzeplein 1, 9700 RB Groningen, The Netherlands.
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Ainslie KM, Desai TA. Microfabricated implants for applications in therapeutic delivery, tissue engineering, and biosensing. LAB ON A CHIP 2008; 8:1864-78. [PMID: 18941687 PMCID: PMC2970504 DOI: 10.1039/b806446f] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
By adapting microfabrication techniques originally developed in the microelectronics industry novel devices for drug delivery, tissue engineering and biosensing have been engineered for in vivo use. Implant microfabrication uses a broad range of techniques including photolithography, and micromachining to create devices with features ranging from 0.1 to hundreds of microns with high aspect ratios and precise features. Microfabrication offers device feature scale that is relevant to the tissues and cells to which they are applied, as well as offering ease of en masse fabrication, small device size, and facile incorporation of integrated circuit technology. Utilizing these methods, drug delivery applications have been developed for in vivo use through many delivery routes including intravenous, oral, and transdermal. Additionally, novel microfabricated tissue engineering approaches propose therapies for the cardiovascular, orthopedic, and ocular systems, among others. Biosensing devices have been designed to detect a variety of analytes and conditions in vivo through both enzymatic-electrochemical reactions and sensor displacement through mechanical loading. Overall, the impact of microfabricated devices has had an impact over a broad range of therapies and tissues. This review addresses many of these devices and highlights their fabrication as well as discusses materials relevant to microfabrication techniques.
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Affiliation(s)
- Kristy M. Ainslie
- Department of Bioengineering and Therapeutic Sciences; Department of Physiology University of California, San Francisco
| | - Tejal A. Desai
- Department of Bioengineering and Therapeutic Sciences; Department of Physiology University of California, San Francisco
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17
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Artificial cells: building bioinspired systems using small-scale biology. Trends Biotechnol 2008; 26:14-20. [DOI: 10.1016/j.tibtech.2007.09.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 09/25/2007] [Accepted: 09/26/2007] [Indexed: 12/21/2022]
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18
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Cosentino C, Amato F, Walczak R, Boiarski A, Ferrari M. Dynamic model of biomolecular diffusion through two-dimensional nanochannels. J Phys Chem B 2007; 109:7358-64. [PMID: 16851842 DOI: 10.1021/jp045478u] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular diffusion dynamics in unconstrained cases has been studied thoroughly during the last two centuries, leading to the well-known Fick's diffusion laws and Stokes-Einstein equation. More recently, a new impulse to the study of this topic has been provided by the necessity of understanding the behavior of solute particles in the presence of environmental constraints of size comparable to the molecular dimensions. In this work, we investigate the diffusion kinetics of biomolecules, such as bovine serum albumin, interferon, and lysozyme, through microfabricated silicon membranes, having pores of nanometric size in only one dimension, in the range from few to tens of nanometers (the other dimensions are in the mum range). Experimental results show that the diffusion profiles, in some cases, deviate substantially from those predicted by Fick's laws. In light of these results, a new diffusion mathematical model is proposed, which can reasonably explain the phenomenon and, at the same time, recovers the classical diffusion laws in the unconstrained case. Moreover, a physical description, derived from van der Waals equation of state, is presented, and it is compared with the results obtained by the mathematical model.
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Affiliation(s)
- Carlo Cosentino
- Department of Experimental and Clinical Medicine, Università degli Studi Magna Graecia di Catanzaro, via T. Campanella 115, 88100 Catanzaro, Italy.
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Amato F, Cosentino C, Pricl S, Ferrone M, Fermeglia M, Cheng MMC, Walczak R, Ferrari M. Multiscale modeling of protein transport in silicon membrane nanochannels. Part 2. From molecular parameters to a predictive continuum diffusion model. Biomed Microdevices 2007; 8:291-8. [PMID: 17003963 DOI: 10.1007/s10544-006-0032-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transport and surface interactions of proteins in nanopore membranes play a key role in many processes of biomedical importance. Although the use of porous materials provides a large surface-to-volume ratio, the efficiency of the operations is often determined by transport behavior, and this is complicated by the fact that transport paths (i.e., the pores) are frequently of molecular dimensions. Under these conditions, a protein diffusion can be slower than predicted from Fick law. The main contribution of this paper is the development of a mathematical model of this phenomenon, whose parameters are computed via molecular modeling, as described Part 1. Our multiscale modeling methodology, validated by using experimental results related to the diffusion of lysozyme molecules, constitutes an "ab initio" recipe, for which no experimental data are needed to predict the protein release, and can be tailored in principle to match any different protein and any different surface, thus filling gap between the nano and the macroscale.
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Affiliation(s)
- Francesco Amato
- Department of Experimental and Clinical Medicine, Università degli Studi Magna Graecia, via T. Campanella 115, 88100 Catanzaro, Italy
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de Vos P, Faas MM, Strand B, Calafiore R. Alginate-based microcapsules for immunoisolation of pancreatic islets. Biomaterials 2006; 27:5603-17. [PMID: 16879864 DOI: 10.1016/j.biomaterials.2006.07.010] [Citation(s) in RCA: 350] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 07/11/2006] [Indexed: 01/12/2023]
Abstract
Transplantation of microencapsulated cells is proposed as a therapy for the treatment of a wide variety of diseases since it allows for transplantation of endocrine cells in the absence of undesired immunosuppression. The technology is based on the principle that foreign cells are protected from the host immune system by an artificial membrane. In spite of the simplicity of the concept, progress in the field of immunoisolation has been hampered for many years due to biocompatibility issues. During the last years important advances have been made in the knowledge of the characteristics and requirements capsules have to meet in order to provide optimal biocompatibility and survival of the enveloped tissue. Novel insight shows that not only the capsules material but also the enveloped cells should be hold responsible for loss of a significant portion of the immunoisolated cells and, thus, failure of the grafts on the long term. Microcapsules without cells can be produced as such that they remain free of any significant foreign body response for prolonged periods of time in both experimental animals and humans. New approaches in which newly discovered inflammatory responses are silenced bring the technology of transplantation of immunoisolated cells close to clinical application.
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Affiliation(s)
- Paul de Vos
- Department of Pathology and Laboratory Medicine, Division of Medical Biology, University Hospital of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
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LeDuc PP, LeDuc PR, Bellin RR, Bellin RM. Nanoscale intracellular organization and functional architecture mediating cellular behavior. Ann Biomed Eng 2006; 34:102-13. [PMID: 16456640 DOI: 10.1007/s10439-005-9008-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Accepted: 06/30/2005] [Indexed: 10/25/2022]
Abstract
Cells function based on a complex set of interactions that control pathways resulting in ultimate cell fates including proliferation, differentiation, and apoptosis. The inter-workings of this immensely dense network of intracellular molecules are influenced by more than random protein and nucleic acid distribution where their interactions culminate in distinct cellular function. By probing the design of these biological systems from an engineering perspective, researchers can gain great insight that will aid in building and utilizing systems that are on this size scale where traditional large-scale rules may fail to apply. The organized interaction and gradient distribution in intracellular space imply a structural architecture that modulates cellular processes by influencing biochemical interactions including transport and binding-reactions. One significant structure that plays a role in this modulation is the cell cytoskeleton. Here, we discuss the cytoskeleton as a central and integrating functional structure in influencing cell processes and we describe technology useful for probing this structure. We explain the nanometer scale science of cytoskeletal structure with respect to intracellular organization, mechanotransduction, cytoskeletal-associated proteins, and motor molecules, as well as nano- and microtechnologies that are applicable for experimental studies of the cytoskeleton. This biological architecture of the cytoskeleton influences molecular, cellular, and physiological processes through structured multimodular and hierarchical principles centered on these functional filaments. Through investigating these organic systems that have evolved over billions of years, understanding in biology, engineering, and nanometer-scaled science will be advanced.
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Affiliation(s)
- Philip P LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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22
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Lacík I. Polymer Chemistry in Diabetes Treatment by Encapsulated Islets of Langerhans: Review to 2006. Aust J Chem 2006. [DOI: 10.1071/ch06197] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Polymeric materials have been successfully used in numerous medical applications because of their diverse properties. For example, development of a bioartificial pancreas remains a challenge for polymer chemistry. Polymers, as a form of various encapsulation device, have been proposed for designing the semipermeable membrane capable of long-term immunoprotection of transplanted islets of Langerhans, which regulate the blood glucose level in a diabetic patient. This review describes the current situation in the field, discussing aspects of material selection, encapsulation devices, and encapsulation protocols. Problems and unanswered questions are emphasized to illustrate why clinical therapies with encapsulated islets have not been realized, despite intense activity over the past 15 years. The review was prepared with the goal to address professionals in the field as well as the broad polymer community to help in overcoming final barriers to the clinical phase for transplantation of islets of Langerhans encapsulated in a polymeric membrane.
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La Flamme KE, Mor G, Gong D, La Tempa T, Fusaro VA, Grimes CA, Desai TA. Nanoporous alumina capsules for cellular macroencapsulation: transport and biocompatibility. Diabetes Technol Ther 2005; 7:684-94. [PMID: 16241869 DOI: 10.1089/dia.2005.7.684] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Currently, the most widely used treatment for diabetes is the daily subcutaneous injection of recombinant human insulin. Daily injections, however, cannot match the physiological biphasic behavior of normal insulin release, nor can they precisely meet the demands of food intake, exercise, and stress. Cellular encapsulation, or immunoisolation, is a possible solution to this problem. This cell-based therapy allows patients to receive the benefits of more physiological insulin and blood glucose regulation, without the need for immunosuppressants that are associated with organ or cell transplantation. METHODS Immunoisolation capsules were fabricated out of aluminum and aluminum oxide using a two-step anodization procedure. The diffusion behavior of glucose, immunoglobulin G (IgG), and insulin were measured. Furthermore, the functionality and viability of encapsulated MIN6 cells were tested. Finally, live cells were stained and imaged using confocal microscopy. RESULTS Data indicated that this device is effective in allowing the transport of relevant molecules such as glucose and insulin, while at the same time significantly impeding the transport of IgG, suggesting that it would be efficacious in protecting cell grafts in vivo. Furthermore, encapsulated cells were able to respond dynamically to glucose input signals. Finally, cell staining showed that the viability of encapsulated cells is maintained after 24 h, although the cells appear to be more heavily concentrated at the area that is closest to the membrane. CONCLUSIONS This study has shown that nanoporous alumina membranes, with well-controlled pore sizes, can be used for the encapsulation of therapeutic cells and may provide an alternative encapsulation strategy for the treatment of diabetes.
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Affiliation(s)
- Kristen E La Flamme
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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Martin F, Walczak R, Boiarski A, Cohen M, West T, Cosentino C, Shapiro J, Ferrari M. Tailoring width of microfabricated nanochannels to solute size can be used to control diffusion kinetics. J Control Release 2005; 102:123-33. [PMID: 15653139 DOI: 10.1016/j.jconrel.2004.09.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Accepted: 09/28/2004] [Indexed: 10/26/2022]
Abstract
Top-down microfabrication techniques were used to create silicon-based membranes consisting of arrays of uniform channels having a width as small as 7 nm. The measurement of diffusion kinetics of solutes across these membranes under sink conditions reveals non-Fickian behavior as the nanopore width approaches the hydrodynamic diameter of the solute. Zero-order diffusion of interferon is observed at channel width of 20 nm, and the same phenomenon occurs with albumin and 13-nm-wide channels, whereas Fickian diffusion kinetics is seen at 26 nm and larger pore sizes. A prototypical drug delivery device is described that is fitted with a 13-nm nanopore membrane and loaded with radio-labeled BSA. Following subcutaneous implantation in rats, diffusion from the device provided prolonged levels of BSA in the blood. Such a nonmechanical device offers important advantages in drug delivery applications, including zero-order release and high loading capacity.
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Hutmacher DW, Sittinger M, Risbud MV. Scaffold-based tissue engineering: rationale for computer-aided design and solid free-form fabrication systems. Trends Biotechnol 2004; 22:354-62. [PMID: 15245908 DOI: 10.1016/j.tibtech.2004.05.005] [Citation(s) in RCA: 531] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
One of the milestones in tissue engineering has been the development of 3D scaffolds that guide cells to form functional tissue. Recently, mouldless manufacturing techniques, known as solid free-form fabrication (SFF), or rapid prototyping, have been successfully used to fabricate complex scaffolds. Similarly, to achieve simultaneous addition of cells during the scaffold fabrication, novel robotic assembly and automated 3D cell encapsulation techniques are being developed. As a result of these technologies, tissue-engineered constructs can be prepared that contain a controlled spatial distribution of cells and growth factors, as well as engineered gradients of scaffold materials with a predicted microstructure. Here, we review the application, advancement and future directions of SFF techniques in the design and creation of scaffolds for use in clinically driven tissue engineering.
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Affiliation(s)
- Dietmar W Hutmacher
- Division of Bioengineering and Department of Orthopaedic Surgery, National University of Singapore, 119260, Singapore.
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Gimi B, Eroglu S, Leoni L, Desai TA, Magin RL, Roman BB. NMR spiral surface microcoils: Applications. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/cmr.b.10073] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Orive G, Hernández RM, Gascón AR, Calafiore R, Chang TMS, De Vos P, Hortelano G, Hunkeler D, Lacík I, Shapiro AMJ, Pedraz JL. Cell encapsulation: promise and progress. Nat Med 2003; 9:104-7. [PMID: 12514721 DOI: 10.1038/nm0103-104] [Citation(s) in RCA: 472] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Gorka Orive
- Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country, Vitoria-Gasteiz, Spain
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