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Poly(L-lactide-co-glycolide) (85/15) (PLGA) was synthesized by ring-opening co-polymerization and characterized by infrared spectroscopy (IR) and gel-permeation chromatography (GPC). The PLGA conduits for peripheral nerve regeneration were fabricated and implanted into the transected sciatic nerve in rats. The biocompatibility test was carried out in vitro and in vivo. The extracts from PLGA are demonstrated to be non-cytotoxic, and the cells form confluent layers in medium containing extracts from PLGA after 2 weeks. The tissue response in vivo shows that the inflammatory response to PLGA continues to decrease, which indicates that PLGA has a good biocompatibility. The trial of the implant in vivo shows PLGA conduits in rats have the functions of bridging and promoting regeneration of injured peripheral nerve.

Titanium alloy scaffolds with a porous structure have attracted much attention in bone defect repair. However, which pore structure is more beneficial to bone defect repair is controversial. In the present research, the Ti6Al4V alloy porous scaffolds with gradient pore sizes were designed and fabricated. The microstructure characterization, tests of mechanical properties, and in vitro and in vivo experiments have been performed to systematically evaluate the effect of pore size on osteoinduction and osteogenesis. The results revealed that the contact angle with water, compressive strength, and elastic modulus of the Ti6Al4V alloy porous scaffolds decreased gradually with the increase of pore size. However, there were obvious drops when the pore size of the porous scaffold was around 600 μm. As the pore size increased, the proliferation and integrin β1 of RAW 264.7 macrophages seeded on Ti6Al4V alloy porous scaffolds increased at first, reaching a maximum value at a pore size of around 600 μm, and then decreased subsequently. The proliferation, integrin β1, and osteogenic gene-related expressions of Bone marrow mesenchymal stem cells (BMSCs) seeded on Ti6Al4V alloy porous scaffolds with different pore sizes all exhibited similar variations which rose with increased pore size firstly, obtaining the maximum value at pore size about 600 μm, and then declined. The in vivo experiments confirmed the in vitro results, and the Ti6Al4V alloy porous scaffold with a pore size of 600 μm possessed the better capability to induce new bone formation. Therefore, for the design of Ti6Al4V alloy with a regular porous scaffold, the surface morphology, porosity, strength, and elastic modulus should be considered systematically, which would determine the capability of osteoinduction and osteogenesis.