HIGH MODULUS SILICATES/POLY (L-LACTIC ACID) BASED POLYMERS ASSEMBLIES FOR POTENTIAL APPLICATIONS IN TISSUE ENGINEERING

In this paper, silicates/poly (l-lactic acid)-co-bisphenol A epoxy resin assemblies with high modulus were developed by in situpolymerization of l-lactic acid and surface-modified lamellar vermiculites for potential applications in tissue engineering. These assemblies represented advances in the mechanical properties that can be hardly obtained in other assemblies formed via physical interactions. The covalent grafting of the PLLA based polymers onto the vermiculites surface was confirmed by X-ray photon spectroscopy. The elastic moduli of the assemblies measured by an atomic force microscope were around 7 GPa, and higher than the elastic moduli of the pure polymer (3.2 GPa) and unmodified vermiculites (1.5 GPa), respectively. Images demonstrated that cells proliferated and reached confluence on both the assemblies and pure polymer materials, which indicated that the assemblies exhibited the similar cytocompatibility with pure polymer. With the addition of 5 wt.% assemblies, the polymer and assemblies blended-composites exhibited a 118% improvement in compressive strength and 117% improvement in modulus compared with pure polymer. The present work demonstrated a strategy for the assembly of biomacromolecules and inorganic layers and fabrication of biomaterials high in modulus for tissue engineering applications.