Effects of surface modification on the mechanical and structural properties of nanofibrous poly(ε-caprolactone)/forsterite scaffold for tissue engineering applications.

Composite scaffolds consisting of polymers reinforced with ceramic nanoparticles are widely applied for hard tissue engineering. However, due to the incompatible polarity of ceramic nanoparticles with polymers, they tend to agglomerate in the polymer matrix which results in undesirable effects on the integral properties of composites. In this research, forsterite (Mg2SiO4) nanoparticles was surface esterified by dodecyl alcohol and nanofibrous poly(ε-caprolactone)(PCL)/modified forsterite scaffolds were developed through electrospinning technique. The aim of this research was to investigate the properties of surface modified forsterite nanopowder and PCL/modified forsterite scaffolds, before and after hydrolytic treatment, as well as the cellular attachment and proliferation. Results demonstrated that surface modification of nanoparticles significantly enhanced the tensile strength and toughness of scaffolds upon 1.5- and 4-folds compared to unmodified samples, respectively, due to improved compatibility between matrix and filler. Hydrolytic treatment of scaffolds also modified the bioactivity and cellular attachment and proliferation due to greatly enhanced hydrophilicity of the forsterite nanoparticles after this process compared to surface modified samples. Results suggested that surface modification of forsterite nanopowder and hydrolytic treatment of the developed scaffolds were effective approaches to address the issues in the formation of composite fibers and resulted in development of bioactive composite scaffolds with ideal mechanical and structural properties for bone tissue engineering applications.

Development of novel aligned nanofibrous composite membranes for guided bone regeneration.

The ability to mimic the structure of the natural extracellular matrix is a successful key for guided bone regeneration (GBR). For the regeneration of highly organized structures such as heart and bone, aligned fibrous membranes could provide anisotropic mechanical and biological properties which are adequate topographic guidance to cells. Here, novel nanofibrous membranes were developed through electrospinning of PCL-forsterite nanopowder. The membranes were characterized with regard to structural and mechanical properties, degradation, bioactivity and cellular interactive responses. Results showed that optimized nanofibrous composite membrane with significantly improved tensile strength and elastic modules was achieved through addition of 10 wt% forsterite nanopowder into PCL membrane. Addition of forsterite nanopowder decreased the average fiber diameters from 872±361 nm (pure PCL membrane) to 258±159 nm (PCL-10 wt% forsterite membrane). At higher forsterite contents (>10 wt%), the agglomeration of nanoparticles was observed which resulted in reduced mechanical properties. Aligned fibrous membranes revealed smaller fiber sizes and significantly enhanced and anisotropic mechanical properties compared to random ones suggesting that fiber alignment has a profound effect on the structural properties of membranes. Forsterite nanopowder increased the degradation rate showing enhanced hydrophilicity and induced apatite formation in simulated body fluid. Furthermore, composite nanofibrous membranes possessed significantly improved cellular responses in terms of attachment, proliferation and mineralization of pre-osteoblasts compared to PCL membrane. Thus, the currently developed nanofibrous composite membranes embedded in forsterite nanopowder expected to be attractive in GBR membrane applications.