The mechanical characteristics and in vitro biocompatibility of poly(glycerol sebacate)-bioglass elastomeric composites.
ABSTRACT Biodegradable elastomeric materials have gained much recent attention in the field of soft tissue engineering. Poly(glycerol sebacate) (PGS) is one of a new family of elastomers which are promising candidates used for soft tissue engineering. However, PGS has a limited range of mechanical properties and has drawbacks, such as cytotoxicity caused by the acidic degradation products of very soft PGS and degradation kinetics that are too fast in vivo to provide sufficient mechanical support to the tissue. However, the development of PGS/based elastomeric composites containing alkaline bioactive fillers could be a method for addressing these drawbacks and thus may pave the way towards wide clinical applications. In this study, we synthesized a new PGS composite system consisting of a micron-sized Bioglass filler. In addition to much improved cytocompatibility, the PGS/Bioglass composites demonstrated three remarkable mechanical properties. First, contrary to previous reports, the addition of microsized Bioglass increases the elongation at break from 160 to 550%, while enhancing the Young's modulus of the composites by up to a factor of four. Second, the modulus of the PGS/Bioglass composites drops abruptly in a physiological environment (culture medium), and the level of drop can be tuned such that the addition of Bioglass does not harden the composite in vivo and thus the desired compliance required for soft tissue engineering are maintained. Third, after the abrupt drop in modulus, the composites exhibited mechanical stability over an extended period. This latter observation is an important feature of the new composites, because they can provide reliable mechanical support to damaged tissues during the lag phase of the healing process. These mechanical properties, together with improved biocompatibility, make this family of composites better candidates than plastic and related composite biomaterials for the applications of tissue engineering.
SourceAvailable from: Ivan Djordjevic[Show abstract] [Hide abstract]
ABSTRACT: Bone can be affected by osteosarcomae requiring surgical excision of the tumor as part of the treatment regime. Complete removal of cancerous cells is difficult and conventionally requires the removal of a margin of safety around the tumor to offer improved patient prognosis. This work considers a novel series of composite scaffolds based on poly(octanediol citrate) (POC) impregnated with gallium-based bioglass microparticles for possible incorporation into bone following tumor removal. The objective of this research was to fabricate and characterize these scaffolds and subsequently report on their mechanical and biological properties. The porous microcomposite scaffolds with various concentrations of bioglass (10, 20, 30 wt%) incorporated were fabricated using a salt leaching technique. The scaffolds exhibited compression modulus in the range of 0.3–7 MPa. The addition of bioglass increased the mechanical properties even though porosity increased. Furthermore, increasing the concentration of bioglass had a significant influence on glass transition temperature from 2.5 °C for the pure polymer to around 25 °C for 30 % bioglass-containing composite. The ion release study revealed that composites containing 10 % bioglass had the highest ion release ratio after 28 days of soaking in phosphate buffered saline. The interaction of bioglass phase with POC led to the formation of additional ionic crosslinks aside from covalent crosslinks which further resulted in increased stiffness and decreased weight loss. The osteoblast cells were well attached and growth on composites and collagen synthesis increased particularly with the 10 % bioglass concentration.Journal of Materials Science 03/2015; 50(5). DOI:10.1007/s10853-014-8782-2 · 2.31 Impact Factor
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ABSTRACT: Fabrication of nonlinear elastic materials that resemble biological tissues remains a challenge in biomaterials research. Here, a new fabrication protocol to produce elastomeric fibrous scaffolds was established, using the core/shell electrospinning technique. A prepolymer of poly(xylitol sebacate) with a 2:5 mol ratio of xylitol:sebacic acid (PXS2:5) was first formulated, then co-electrospun with polyvinyl alcohol (PVA - 95,000 Mw). After cross-linking of core polymer PXS2:5, the PVA shells were rinsed off in water, leaving a porous elastomeric network of PXS2:5 fibres. Under aqueous conditions, the PXS2:5 fibrous scaffolds exhibited stable, nonlinear J-shaped stress-strain curves, with large average rupture elongation (76%) and Young's modulus (~1.0 MPa), which were in the range of muscle tissue. Rupture elongation of PXS2:5 was also much higher when electrospun, compared to 2D solid sheets (45%). In direct contact with cell monolayers under physiological conditions, PXS2:5 scaffolds were as biocompatible as those made of poly-L-lactic acid (PLLA), with improvements over culture medium alone. In conclusion, the newly developed porous PXS2:5 scaffolds show tissue-like mechanical properties and excellent biocompatibility, making them very promising for bioengineering of soft tissues and organs.Journal of the Mechanical Behavior of Biomedical Materials 09/2014; DOI:10.1016/j.jmbbm.2014.08.027 · 3.05 Impact Factor
11/2011; 3(2):34-47. DOI:10.1179/1758897911Y.0000000003