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Lee JK, Yao SX, Li G, Jun MBG, Lee PC. Measurement Methods for Solubility and Diffusivity of Gases and Supercritical Fluids in Polymers and Its Applications. POLYM REV 2017. [DOI: 10.1080/15583724.2017.1329209] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Jason K. Lee
- Department of Mechanical Engineering, University of Victoria, Victoria, BC, Canada
| | - Selina X. Yao
- Department of Mechanical Engineering, University of Vermont, Burlington, Vermont, USA
| | | | - Martin B. G. Jun
- Department of Mechanical Engineering, University of Victoria, Victoria, BC, Canada
| | - Patrick C. Lee
- Department of Mechanical Engineering, University of Vermont, Burlington, Vermont, USA
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Qu H, Bhattacharyya S, Ducheyne P. Silicon oxide based materials for controlled release in orthopedic procedures. Adv Drug Deliv Rev 2015; 94:96-115. [PMID: 26032046 DOI: 10.1016/j.addr.2015.05.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/21/2015] [Accepted: 05/25/2015] [Indexed: 12/14/2022]
Abstract
By virtue of excellent tissue responses in bone tissue, silicon oxide (silica) based materials have been used for bone tissue engineering. Creating nanoscale porosity within silica based materials expands their applications into the realm of controlled release area. This additional benefit of silica based materials widens their application in the orthopedic fields in a major way. This review discusses the various chemical and physical forms of silica based controlled release materials, the release mechanisms, the applications in orthopedic procedures and their overall biocompatibility.
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TSUTSUMI C, TSUZUKI A, HARA T, NAKAYAMA Y, SHIONO T. Study on the Use of Supercritical Carbon Dioxide as a Solvent to Prepare Novel, Efficient Controlled-Release Materials. KOBUNSHI RONBUNSHU 2014. [DOI: 10.1295/koron.71.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cabezas L, Gracia I, García M, de Lucas A, Rodríguez J. Production of biodegradable porous scaffolds impregnated with 5-fluorouracil in supercritical CO2. J Supercrit Fluids 2013. [DOI: 10.1016/j.supflu.2013.03.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Duarte ARC, Santo VE, Alves A, Silva SS, Moreira-Silva J, Silva TH, Marques AP, Sousa RA, Gomes ME, Mano JF, Reis RL. Unleashing the potential of supercritical fluids for polymer processing in tissue engineering and regenerative medicine. J Supercrit Fluids 2013. [DOI: 10.1016/j.supflu.2013.01.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Girotra P, Singh SK, Nagpal K. Supercritical fluid technology: a promising approach in pharmaceutical research. Pharm Dev Technol 2012; 18:22-38. [DOI: 10.3109/10837450.2012.726998] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Bonani W, Motta A, Migliaresi C, Tan W. Biomolecule gradient in micropatterned nanofibrous scaffold for spatiotemporal release. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13675-13687. [PMID: 22950580 PMCID: PMC3648342 DOI: 10.1021/la302386u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Controlled molecule release from scaffolds can dramatically increase the scaffold ability of directing tissue regeneration in vitro and in vivo. Crucial to the regeneration is precise regulation over release direction and kinetics of multiple molecules (small genes, peptides, or larger proteins). To this end, we developed gradient micropatterns of electrospun nanofibers along the scaffold thickness through programming the deposition of heterogeneous nanofibers of poly(ε-caprolactone) (PCL) and poly(D,L-lactide-co-glycolide) acid (PLGA). Confocal images of the scaffolds containing fluorophore-impregnated nanofibers demonstrated close matching of actual and designed gradient fiber patterns; thermal analyses further showed their matching in the composition. Using acid-terminated PLGA (PLGAac) and ester-terminated PLGA (PLGAes) to impregnate molecules in the PCL-PLGA scaffolds, we demonstrated for the first time their differences in nanofiber degeneration and molecular weight change during degradation. PLGAac nanofibers were more stable with gradual and steady increase in the fiber diameter during degradation, resulting in more spatially confined molecule delivery from PCL-PLGA scaffolds. Thus, patterns of PCL-PLGAac nanofibers were used to design versatile controlled delivery scaffolds. To test the hypothesis that molecule-impregnated PLGAac in the gradient-patterned PCL-PLGAac scaffolds can program various modalities of molecule release, model molecules, including small fluorophores and larger proteins, were respectively used for time-lapse release studies. Gradient-patterns were used as building blocks in the scaffolds to program simultaneous release of one or multiple proteins to one side or, respectively, to the opposite sides of scaffolds for up to 50 days. Results showed that the separation efficiency of molecule delivery from all the scaffolds with a thickness of 200 μm achieved >88% for proteins and >82% for small molecules. In addition to versatile spatially controlled delivery, micropatterns were designed to program sequential release of proteins. The hierarchically structured materials presented here may enable development of novel multifunctional scaffolds with defined 3D dynamic microenvironments for tissue regeneration.
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Affiliation(s)
- Walter Bonani
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
- Department of Materials Engineering and Industrial Technologies, BioTech Research Center and INSTM Research Unit, University of Trento, and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento, 38100, Italy
| | - Antonella Motta
- Department of Materials Engineering and Industrial Technologies, BioTech Research Center and INSTM Research Unit, University of Trento, and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento, 38100, Italy
| | - Claudio Migliaresi
- Department of Materials Engineering and Industrial Technologies, BioTech Research Center and INSTM Research Unit, University of Trento, and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento, 38100, Italy
| | - Wei Tan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
- Departments of Pediatrics and Bioengineering, University of Colorado at Denver, Aurora, Colorado 80045, United States
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Cabezas L, Fernández V, Mazarro R, Gracia I, de Lucas A, Rodríguez J. Production of biodegradable porous scaffolds impregnated with indomethacin in supercritical CO2. J Supercrit Fluids 2012. [DOI: 10.1016/j.supflu.2011.12.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Abstract
Ischemic disease causes a large number of deaths and significant clinical problems worldwide. Therapeutic angiogenesis, strengthened by advances in growth-factor-based therapies, is a promising solution to ischemic pathologies. Major challenges in therapeutic angiogenesis are the lack of stability of native angiogenic proteins and also providing sustained delivery of biologically active proteins at the ischemic sites. This paper will discuss various protein engineering strategies to develop stabilized proangiogenic proteins and several biomaterial technologies used to amplify the angiogenic outcome by delivering biologically active growth factors in a sustained manner.
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Affiliation(s)
- Rituparna Sinha Roy
- Department of Biological and Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur Campus, P O BCKV Campus Mail Office, West Bengal 741252, India.
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Zhao XF, Li XD, Kang YQ, Yuan Q. Improved biocompatibility of novel poly(L-lactic acid)/β-tricalcium phosphate scaffolds prepared by an organic solvent-free method. Int J Nanomedicine 2011; 6:1385-90. [PMID: 21760732 PMCID: PMC3133528 DOI: 10.2147/ijn.s20743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A porous poly(L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) composite scaffold was fabricated using a novel technique comprising powder mixing, compression molding, low-temperature treatment, and particulate leaching without any organic solvent. The effect of this scaffold on osteoblast proliferation and differentiation was evaluated in vitro. The fabricated scaffold had a homogeneously interconnected porous structure with a porosity of 70% and compressive strength of 1.35 MPa. The methylthiazol tetrazolium values and alkaline phosphatase (ALP) activity of osteoblasts seeded on the solvent-free scaffold were significant higher than those of the control. Using real-time PCR, gene expressions of ALP, osteocalcin, and type 1 collagen were shown to be upregulated. As the method does not use any organic solvent, it eliminates problems associated with organic solvent residue and therefore improves the cell compatibility. It has a promising potential for the preparation of porous scaffold for bone tissue engineering.
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Affiliation(s)
- Xue-feng Zhao
- State Key Laboratory of Oral diseases, Sichuan University, Chengdu, People's Republic of China
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11
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Amsden BG. Delivery approaches for angiogenic growth factors in the treatment of ischemic conditions. Expert Opin Drug Deliv 2011; 8:873-90. [DOI: 10.1517/17425247.2011.577412] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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12
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Tsutsumi C, Fukukawa N, Sakafuji J, Oro K, Hata K, Nakayama Y, Shiono T. Impregnation of poly(L-lactide-ran-cyclic carbonate) copolymers with useful compounds with supercritical carbon dioxide. J Appl Polym Sci 2011. [DOI: 10.1002/app.33646] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Humrez L, Ramos M, Al-Jumaily A, Petchu M, Ingram J. Synthesis and characterisation of porous polymer microneedles. JOURNAL OF POLYMER RESEARCH 2010. [DOI: 10.1007/s10965-010-9505-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Bechara SL, Judson A, Popat KC. Template synthesized poly(ɛ-caprolactone) nanowire surfaces for neural tissue engineering. Biomaterials 2010; 31:3492-501. [DOI: 10.1016/j.biomaterials.2010.01.084] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
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Porter JR, Ruckh TT, Popat KC. Bone tissue engineering: a review in bone biomimetics and drug delivery strategies. Biotechnol Prog 2010; 25:1539-60. [PMID: 19824042 DOI: 10.1002/btpr.246] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Critical-sized defects in bone, whether induced by primary tumor resection, trauma, or selective surgery have in many cases presented insurmountable challenges to the current gold standard treatment for bone repair. The primary purpose of a tissue-engineered scaffold is to use engineering principles to incite and promote the natural healing process of bone which does not occur in critical-sized defects. A synthetic bone scaffold must be biocompatible, biodegradable to allow native tissue integration, and mimic the multidimensional hierarchical structure of native bone. In addition to being physically and chemically biomimetic, an ideal scaffold is capable of eluting bioactive molecules (e.g., BMPs, TGF-betas, etc., to accelerate extracellular matrix production and tissue integration) or drugs (e.g., antibiotics, cisplatin, etc., to prevent undesired biological response such as sepsis or cancer recurrence) in a temporally and spatially controlled manner. Various biomaterials including ceramics, metals, polymers, and composites have been investigated for their potential as bone scaffold materials. However, due to their tunable physiochemical properties, biocompatibility, and controllable biodegradability, polymers have emerged as the principal material in bone tissue engineering. This article briefly reviews the physiological and anatomical characteristics of native bone, describes key technologies in mimicking the physical and chemical environment of bone using synthetic materials, and provides an overview of local drug delivery as it pertains to bone tissue engineering is included.
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Affiliation(s)
- Joshua R Porter
- Department of Mechanical Engineering, School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
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Study of cell seeding on porous poly(d,l-lactic-co-glycolic acid) sponge and growth in a Couette–Taylor bioreactor. Chem Eng Sci 2010. [DOI: 10.1016/j.ces.2009.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Zhou H, Chen SB, Peng J, Wang CH. A study of effective diffusivity in porous scaffold by Brownian dynamics simulation. J Colloid Interface Sci 2010; 342:620-8. [DOI: 10.1016/j.jcis.2009.10.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 10/29/2009] [Accepted: 10/29/2009] [Indexed: 11/29/2022]
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18
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Lee LY, Ranganath SH, Fu Y, Zheng JL, Lee HS, Wang CH, Smith KA. Paclitaxel release from micro-porous PLGA disks. Chem Eng Sci 2009. [DOI: 10.1016/j.ces.2009.07.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Porter JR, Henson A, Ryan S, Popat KC. Biocompatibility and mesenchymal stem cell response to poly(epsilon-caprolactone) nanowire surfaces for orthopedic tissue engineering. Tissue Eng Part A 2009; 15:2547-59. [PMID: 19326968 DOI: 10.1089/ten.tea.2008.0476] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Concerns over utilizing autogenous cancellous bone grafts (such as donor-site morbidity, increased surgical time/complication rate, and restricted availability) as the gold-standard treatment for critical-sized defects in bone have motivated the development of a wide variety of sophisticated synthetic bone scaffolds in recent years. In this work, a novel solvent-free template synthesis technique was utilized to fabricate poly(epsilon-caprolactone) (PCL) nanowire surfaces as a building block for the development of three-dimensional bone scaffolds. Bone marrow-derived mesenchymal stem cells (MSCs) were used to characterize the short- and long-term in vitro biocompatibility and cellular response to these surfaces. A 4-week study in rats was conducted to assess in vivo biocompatibility as well. Short-term in vitro studies revealed that PCL nanowire surfaces enhanced MSC response in terms of survivability, viability, cytoskeleton changes, and morphology as compared with control surfaces (smooth PCL and polystyrene). In long-term in vitro studies, nanowire surfaces induced a rapid production of bone extracellular matrix by differentiated MSCs as indicated by accelerated calcium phosphate mineralization, and osteocalcin and osteopontin production. In vivo studies and histological analysis confirmed that nanowire surfaces are biocompatible. Preliminary biodegradation studies were conducted and indicated that rate of PCL biodegradation can, to some extent, be controlled through the inclusion of nanowires and ester-degrading enzymes. In addition to demonstrating enhanced short- and long-term MSC response to PCL nanowire surfaces, this work presents a simple technique for solvent-free fabrication and bioactive molecule encapsulation of biocompatible, biodegradable three-dimensional bone scaffold components and warrants further investigation.
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Affiliation(s)
- Joshua R Porter
- Department of Mechanical Engineering, School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado, USA
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Spadaccio C, Chello M, Trombetta M, Rainer A, Toyoda Y, Genovese JA. Drug releasing systems in cardiovascular tissue engineering. J Cell Mol Med 2009; 13:422-39. [PMID: 19379142 PMCID: PMC3822506 DOI: 10.1111/j.1582-4934.2008.00532.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Heart disease and atherosclerosis are the leading causes of morbidity and mortality worldwide. The lack of suitable autologous grafts has produced a need for artificial grafts; however, current artificial grafts carry significant limitations, including thrombosis, infection, limited durability and the inability to grow. Tissue engineering of blood vessels, cardiovascular structures and whole organs is a promising approach for creating replacement tissues to repair congenital defects and/or diseased tissues. In an attempt to surmount the shortcomings of artificial grafts, tissue-engineered cardiovascular graft (TECVG), constructs obtained using cultured autologous vascular cells seeded onto a synthetic biodegradable polymer scaffold, have been developed. Autologous TECVGs have the potential advantages of growth, durability, resistance to infection, and freedom from problems of rejection, thrombogenicity and donor scarcity. Moreover polymers engrafted with growth factors, cytokines, drugs have been developed allowing drug-releasing systems capable of focused and localized delivery of molecules depending on the environmental requirements and the milieu in which the scaffold is placed. A broad range of applications for compound-releasing, tissue-engineered grafts have been suggested ranging from drug delivery to gene therapy. This review will describe advances in the development of drug-delivery systems for cardiovascular applications focusing on the manufacturing techniques and on the compounds delivered by these systems to date.
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Affiliation(s)
- Cristiano Spadaccio
- Cardiac and Molecular Biology Laboratory, Heart, Lung & Esophageal Surgery Institute University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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TSUTSUMI C, SAKAFUJI J, OKADA M, ORO K, HATA K. Impregnation of Poly(L-lactide-ran-ε-caprolactone) Copolymers with Useful Compounds in Supercritical Carbon Dioxide. KOBUNSHI RONBUNSHU 2009. [DOI: 10.1295/koron.66.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zhu XH, Lee LY, Jackson JSH, Tong YW, Wang CH. Characterization of porous poly(D,L-lactic-co-glycolic acid) sponges fabricated by supercritical CO2 gas-foaming method as a scaffold for three-dimensional growth of Hep3B cells. Biotechnol Bioeng 2008; 100:998-1009. [DOI: 10.1002/bit.21824] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Pini R, Storti G, Mazzotti M, Tai H, Shakesheff KM, Howdle SM. Sorption and swelling of poly(DL-lactic acid) and poly(lactic-co-glycolic acid) in supercritical CO2: An experimental and modeling study. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/polb.21382] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Guan J, Stankus JJ, Wagner WR. Biodegradable elastomeric scaffolds with basic fibroblast growth factor release. J Control Release 2007; 120:70-8. [PMID: 17509717 PMCID: PMC2698790 DOI: 10.1016/j.jconrel.2007.04.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 03/20/2007] [Accepted: 04/02/2007] [Indexed: 10/23/2022]
Abstract
Scaffolds that better approximate the mechanical properties of cardiovascular and other soft tissues might provide a more appropriate mechanical environment for tissue development or healing in vivo. An ability to induce local angiogenesis by controlled release of an angiogenic factor, such as basic fibroblast growth factor (bFGF), from a biodegradable scaffold with mechanical properties more closely approximating soft tissue could find application in a variety of settings. Toward this end biodegradable poly(ester urethane)urea (PEUU) scaffolds loaded with bFGF were fabricated by thermally induced phase separation. Scaffold morphology, mechanical properties, release kinetics, hydrolytic degradation and bioactivity of the released bFGF were assessed. The scaffolds had inter-connected pores with porosities of 90% or greater and pore sizes ranging from 34-173 microm. Scaffolds had tensile strengths of 0.25-2.8 MPa and elongations at break of 81-443%. Incorporation of heparin into the scaffold increased the initial burst release of bFGF, while the initial bFGF loading content did not change release kinetics significantly. The released bFGF remained bioactive over 21 days as assessed by smooth muscle mitogenicity. Scaffolds loaded with bFGF showed slightly higher degradation rates than unloaded control scaffolds. Smooth muscle cells seeded into the scaffolds with bFGF showed higher cell densities than for control scaffolds after 7 days of culture. The bFGF-releasing PEUU scaffolds thus exhibited a combination of mechanical properties and bioactivity that might be attractive for use in cardiovascular and other soft tissue applications.
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Affiliation(s)
- Jianjun Guan
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Dr., Pittsburgh, Pennsylvania, 15219
| | - John J. Stankus
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261
| | - William R. Wagner
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Dr., Pittsburgh, Pennsylvania, 15219
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261
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Chattopadhyay P, Huff R, Shekunov BY. Drug encapsulation using supercritical fluid extraction of emulsions. J Pharm Sci 2006; 95:667-79. [PMID: 16447174 DOI: 10.1002/jps.20555] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The current work was aimed at evaluating a new method, supercritical fluid extraction of emulsions (SFEE), for the production of composite (e.g., polymer-drug) micro- and nanoparticles, intended for application in sustained-release drug delivery formulations. Using the proposed method, composite particles were obtained, both in a continuous or batch manner by supercritical carbon dioxide extraction of oil-in-water (o/w) emulsions. Model drugs indomethacin and ketoprofen and biodegradable polymers poly(lactic/glycolic) acid and Eudragit RS were used in order to demonstrate the effectiveness of the SFEE process for producing these particles. Stable aqueous suspensions of composite micro and nanoparticles, having sizes ranging between 0.1 and 2 microm were consistently obtained. Emulsion droplet diameter was found to be the major size control parameter. Other parameters investigated included polymer and drug concentrations in solvent and emulsion solvent fraction. The residual solvent content in the particle suspension obtained was consistently below 50 ppm. Standard dissolution tests were used to observe the sustained release phenomenon of the composite particles. The dissolution profile was characterized in terms of the intrinsic dissolution kinetic coefficients taking into account the specific surface area and solubility of the particles. It was observed that the kinetic coefficient parameter for encapsulated drugs was reduced by 2-4 orders of magnitude when compared to the unprocessed drug particles.
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Affiliation(s)
- P Chattopadhyay
- Posnick Center of Innovative Technology, Ferro Corporation, Independence, Ohio 44131, USA
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Nalawade SP, Picchioni F, Janssen L. Supercritical carbon dioxide as a green solvent for processing polymer melts: Processing aspects and applications. Prog Polym Sci 2006. [DOI: 10.1016/j.progpolymsci.2005.08.002] [Citation(s) in RCA: 460] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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