Poly(glycerol sebacate) (PGS) has been proposed to engineering soft tissues due to its elastomeric properties, biocompatibility, linear degradation rate and non-toxic byproducts. However, one of the problems with PGS is low mechanical stiffness, that limits its application to soft tissues engineering. Here we report the synthesis and characterizations of highly elastomeric and mechanically stiff nanocomposites by covalently reinforcing PGS network with synthetic silicate nanoplatelets. Synthetic silicates are plate-like polyions composed of simple or complex salts of silicic acids and are recently shown to induce osteogenic differentiation of stem cells without using any growth factors. When subjected to thermal curing process at 130 oC, the additional hydroxyl groups (-OH) present on PGS prepolymer reacted with (-OH) present on silicate nanoparticles and unreacted sebacic acid to form covalently crosslinked networks (Figure 1a & 1b). Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/marm_2010/uploads/33047_marm.jpg' alt='' />By tailoring the crosslinking density, it is possible to engineer scaffolds with customized mechanical stiffness, hydration properties (contact angle measurements, Figure 2a) and degradation characteristics. The addition of silicate nanoplatelets significantly enhanced the mechanical strength of the polymeric networks (Figure 2b). The compressive strength and the energy absorbed during the compressive cycle (loading and unloading) increased with increasing silicate nanoplatelets (Figure 2c). This was mainly attributed to the covalently crosslinking of silicate nanoplatelets to PGS networks.The degradation studies showed that the addition of silicates significantly reduced the degradation rate of nanocomposites by more than 50%. The addition of silicate nanoplatelets also enhanced the in vitro bioactivity of polymeric scaffolds. Preliminary in vitro studies showed enhanced cellular adhesion and proliferation of hMSCs on PGS-silicate nanocomposites compared to PGS. Overall, the unique combination of high mechanical stiffness, elastomeric nature and bioactive character of PGS-silicate nanocomposite may be processed to design scaffolds for musculoskeletal tissue engineering.

Engineering elastomeric and mechanically stiff nanocomposite by covalently crosslinking poly(glycerol sebacate) and silicate nanoplatelets

247th National Meeting (2014)

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