A tough biodegradable elastomer

Department of Chemical Engineering, 77 Massachusetts Avenue, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Nature Biotechnology (Impact Factor: 41.51). 07/2002; 20(6):602-6. DOI: 10.1038/nbt0602-602
Source: PubMed


Biodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. A strong, biodegradable, and biocompatible elastomer could be useful for fields such as tissue engineering, drug delivery, and in vivo sensing. We designed, synthesized, and characterized a tough biodegradable elastomer from biocompatible monomers. This elastomer forms a covalently crosslinked, three-dimensional network of random coils with hydroxyl groups attached to its backbone. Both crosslinking and the hydrogen-bonding interactions between the hydroxyl groups likely contribute to the unique properties of the elastomer. In vitro and in vivo studies show that the polymer has good biocompatibility. Polymer implants under animal skin are absorbed completely within 60 days with restoration of the implantation sites to their normal architecture.

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    • "Comparing to other widely used synthetic polymers such as poly(lactic acid) (PLA) and poly(lactic-co-glycolic acid)(PLGA)-based materials, PGS triggered lower inflammatory responses and minimal fibrous encapsulation [35] [36] [37]. As a consequence, PGS-based scaffolds are explored for various soft tissue engineering applications, including vascular graft [39] [40] [41], nerve guide [42], cardiac patch [43], cartilage tissue [44], and retinal transplantation [45]. "
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    ABSTRACT: Poly(glycerol sebacate) (PGS) has been proposed for tissue engineering applications owing to its tough elastomeric mechanical properties, biocompatibility and controllable degradation. However, PGS shows limited bioactivity and thus constraining its utilization for musculoskeletal tissue engineering. To address this issue, we developed bioactive, highly elastomeric, and mechanically stiff nanocomposites by covalently reinforcing PGS network with two-dimensional (2D) nanosilicates. Nanosilicates are ultrathin nanomaterials and can induce osteogenic differentiation of human stem cells in the absence of any osteogenic factors such as dexamethasone or bone morphogenetic proteins-2 (BMP2). The addition of nanosilicate to PGS matrix significantly enhances the mechanical stiffness without affecting the elastomeric properties. Moreover, nanocomposites with higher amount of nanosilicates have higher in vitro stability as determined by degradation kinetics. The increase in mechanical stiffness and in vitro stability is mainly attributed to enhanced interactions between nanosilicates and PGS. We evaluated the in vitro bioactivity of nanocomposite using MC-3T3 preosteoblast cells. The addition of nanosilicates significantly enhances the cell adhesion, support cell proliferation, upregulate alkaline phosphates and mineralized matrix production. Overall, the combination of high mechanically stiffness and elastomericity, tailorable degradation profile, and the ability to promote osteogenic differentiation of PGS-nanosilicate can be used for regeneration of bone. Copyright © 2015. Published by Elsevier Ltd.
    Acta biomaterialia 10/2015; 26:34–44. · 6.03 Impact Factor
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    • "Briefly, n mech was calculated based on the theory of rubber elasticity , given by Eq. (1) [29] "
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    ABSTRACT: Large three-dimensional poly(glycerol sebacate) (PGS)/poly(L-lactic acid) (PLLA) scaffolds with similar bulk mechanical properties to native low and high stress adapted adipose tissue were fabricated via a freeze-drying and a subsequent curing process. PGS/PLLA scaffolds containing 73 vol.% PGS were prepared using two different organic solvents, resulting in highly interconnected open-pore structures with porosities and pore sizes in the range of 91-92% and 109-141 μm, respectively. Scanning electron microscopic analysis indicated that the scaffolds featured different microstructure characteristics, depending on the organic solvent in use. The PGS/PLLA scaffolds had a tensile Young's modulus of 0.030 MPa, tensile strength of 0.007 MPa, elongation at the maximum stress of 25% and full shape recovery capability upon release of the compressive load. In vitro degradation tests presented mass losses of 11-16% and 54-55% without and with the presence of lipase enzyme in 31 days, respectively. In vitro cell tests exhibited clear evidence that the PGS/PLLA scaffolds prepared with 1.4-dioxane as the solvent are suitable for culture of adipose derived stem cells. Compared to pristine PLLA scaffolds prepared with the same procedure, these scaffolds provided favourable porous microstructures, good hydrophilic characteristics, and appropriate mechanical properties for soft tissue applications, as well as enhanced scaffold cell penetration and tissue in-growth characteristics. This work demonstrates that the PGS/PLLA scaffolds have potential for applications in adipose tissue engineering. Copyright © 2015. Published by Elsevier Ltd.
    Acta Biomaterialia 03/2015; 18. DOI:10.1016/j.actbio.2015.03.004 · 6.03 Impact Factor
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    • "The brittle nature of poly(lactides) requires modification in order to be useful as biomedical materials [6]. The need for biodegradable elastomeric polymers for medical implants and porous scaffolds in tissue engineering has been documented in recent years [7] [8] [9]. The suitability of poly trimethylene carbonate (TMC) for the preparation of biomedical implants has also been evaluated [10]. "
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    ABSTRACT: Lactide-based polymers have been widely investigated as materials for tissue engineering. However, characteristics such as low flexibility and elongation tend to limit particular applications, although these can be enhanced by adding plasticizers such as trimethylene carbonate (TMC) to the polymer chain of the copolymer poly(L-lactide-co-D,L-lactide) (PLDLA). The aim of this work was to synthesize and characterize a terpolymer of L-lactide, D,L-lactide, and TMC. The polymers were synthesized from 30% TMC by bulk polymerization and resulted in an average molar mass >10(5) g/mol. Thermal investigation of PLDLA-TMC showed a decrease in the glass transition and onset temperatures compared to PLDLA. PLDLA-TMC scaffolds stimulated the proliferation and normal phenotypic manifestations of cultured osteoblasts. These results show that it was possible to produce a terpolymer from L-lactide, D,L-lactide, and TMC. Scaffolds of this terpolymer had important characteristics that could be useful for applications in bone tissue engineering.
    International Journal of Biomaterials 06/2014; 2014:501789. DOI:10.1155/2014/501789
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