Synthesis of highly porous crosslinked elastin hydrogels and their interaction with fibroblasts in vitro

School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia.
Biomaterials (Impact Factor: 8.31). 07/2009; 30(27):4550-7. DOI: 10.1016/j.biomaterials.2009.05.014
Source: PubMed

ABSTRACT In this study the feasibility of using high pressure CO2 to produce porous alpha-elastin hydrogels was investigated. Alpha-elastin was chemically crosslinked with hexamethylene diisocyanate that can react with various functional groups in elastin such as lysine, cysteine, and histidine. High pressure CO2 substantially affected the characteristics of the fabricated hydrogels. The pore size of the hydrogels was enhanced 20-fold when the pressure was increased from 1 bar to 60 bar. The swelling ratio of the samples fabricated by high pressure CO2 was also higher than the gels produced under atmospheric pressure. The compression modulus of alpha-elastin hydrogels was increased as the applied strain magnitude was modified from 40% to 80%. The compression modulus of hydrogels produced under high pressure CO2 was 3-fold lower than the gels formed at atmospheric conditions due to the increased porosity of the gels produced by high pressure CO2. The fabrication of large pores within the 3D structures of these hydrogels substantially promoted cellular penetration and growth throughout the matrices. The highly porous alpha-elastin hydrogel structures fabricated in this study have potential for applications in tissue engineering.

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Available from: Anthony S Weiss, Aug 18, 2015
    • "In addition to the synthesis of aerogels, supercritical or dense gas technology can be used to create other types of porous scaffolds for tissue engineering applications [27] [28] [29]. Porous scaffolds have been fabricated from both synthetic and natural polymers using supercritical CO 2 foaming, phase inversion, and emulsion template approaches [30] [31] [32] [33] [34] [35] [36]. "
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    ABSTRACT: Silk fibroin (SF) is a natural protein, which is derived from the Bombyx mori silkworm. SF based porous materials are extensively investigated for biomedical applications, due to their biocompatibility and biodegradability. In this work, CO2 assisted acidification is used to synthesize SF hydrogels that are subsequently converted to SF aerogels. The aqueous silk fibroin concentration is used to tune the morphology and textural properties of the SF aerogels. As the aqueous fibroin concentration increases from 2 to 6 wt%, the surface area of the resultant SF aerogels increases from 260 to 308 m(2) g(-1) and the compressive modulus of the SF aerogels increases from 19.5 to 174 kPa. To elucidate the effect of the freezing rate on the morphological and textural properties, SF cryogels are synthesized in this study. The surface area of the SF aerogels obtained from supercritical CO2 drying is approximately five times larger than the surface area of SF cryogels. SF aerogels exhibit distinct pore morphology compared to the SF cryogels. In vitro cell culture studies with human foreskin fibroblast cells demonstrate the cytocompatibility of the silk fibroin aerogel scaffolds and presence of cells within the aerogel scaffolds. The SF aerogels scaffolds created in this study with tailorable properties have potential for applications in tissue engineering.
    Biomedical Materials 05/2015; 10(3):035002. DOI:10.1088/1748-6041/10/3/035002 · 2.92 Impact Factor
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    • "e l s e v i e r. co m/ lo ca t e / b i o m a t e ri a l s in vivo; however, low mechanical properties [23] [24] and a nonhomogenous cell penetration into the 3D structures of these hydrogels [15] are issues. Furthermore, the use of cytotoxic conditions including chemical crosslinkers [15] [25], organic solvents [18] [26], prolonged UV exposure [27] and high pressure [17] [19] in the fabrication of these hydrogels prevents viable cell encapsulation during hydrogel formation. "
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    ABSTRACT: Elastic tissue equivalence is a vital requirement of synthetic materials proposed for many resilient, soft tissue engineering applications. Here we present a bioelastomer made from tropoelastin, the human protein that naturally facilitates elasticity and cell interactions in all elastic tissues. We combined this protein's innate versatility with fast non-toxic fabrication techniques to make highly extensible, cell compatible hydrogels. These hydrogels can be produced in less than a minute through photocrosslinking of methacrylated tropoelastin (MeTro) in an aqueous solution. The fabricated MeTro gels exhibited high extensibility (up to 400%) and superior mechanical properties that outperformed other photocrosslinkable hydrogels. MeTro gels were used to encapsulate cells within a flexible 3D environment and to manufacture highly elastic 2D films for cell attachment, growth, and proliferation. In addition, the physical properties of this fabricated bioelastomer such as elasticity, stiffness, and pore characteristics were tuned through manipulation of the methacrylation degree and protein concentration. This photocrosslinkable, functional tissue mimetic gel benefits from the innate biological properties of a human elastic protein and opens new opportunities in tissue engineering.
    Biomaterials 04/2013; 34(22). DOI:10.1016/j.biomaterials.2013.03.076 · 8.31 Impact Factor
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    • "Several groups have successfully electrospun elastin for use in tissue-engineered grafts [46] [47] [48] [49] [50] [51] [52] and support material for vein grafts [53]. Most, however, have used animal sourced elastin that is [20] [54] [55] [56] extracted from already assembled and cross-linked protein forms. While these forms of elastin may provide the biochemical signaling of elastin, they remain an animal sourced material with the associated potential for immuno-rejection leading to structural degradation and ultimate aneurismal graft failure. "
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    ABSTRACT: The development of vascular grafts has focused on finding a biomaterial that is non-thrombogenic, minimizes intimal hyperplasia, matches the mechanical properties of native vessels and allows for regeneration of arterial tissue. In this study, the structural and mechanical properties and the vascular cell compatibility of electrospun recombinant human tropoelastin (rTE) were evaluated as a potential vascular graft support matrix. Disuccinimidyl suberate (DSS) was used to cross-link electrospun rTE fibers to produce a polymeric recombinant tropoelastin (prTE) matrix that is stable in aqueous environments. Tubular 1cm diameter prTE samples were constructed for uniaxial tensile testing and 4mm small-diameter prTE tubular scaffolds were produced for burst pressure and cell compatibility evaluations from 15 wt.% rTE solutions. Uniaxial tensile tests demonstrated an average ultimate tensile strength (UTS) of 0.36±0.05 MPa and elastic moduli of 0.15±0.04 and 0.91±0.16 MPa, which were comparable to extracted native elastin. Burst pressures of 485±25 mm Hg were obtained from 4mm internal diameter scaffolds with 453±74 μm average wall thickness. prTE supported endothelial cell growth with typical endothelial cell cobblestone morphology after 48 h in culture. Cross-linked electrospun rTE has promising properties for utilization as a vascular graft biomaterial with customizable dimensions, a compliant matrix and vascular cell compatibility.
    Acta biomaterialia 08/2011; 8(1):225-33. DOI:10.1016/j.actbio.2011.08.001 · 5.68 Impact Factor
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