Electrospun Poly(γ-glutamic acid)/β-Tricalcium Phosphate Composite Fibrous Mats for Bone Regeneration

A poly(gamma-glutamic acid)/beta-tricalcium phosphate (gamma-PGA/-TCP) composite fibrous mat was fabricated using the electrospinning technique as a novel bone substitute. The mat was then cross-linked with cystamine in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide to improve its water-resistant ability. Scanning electron micrographs revealed that the gamma-PGA/beta-TCP fibers had a uniform morphology with diameters ranging from 0.64 +/- 0.07 mu m to 1.65 +/- 0.16 mu m. The average diameter of the fibers increased with increasing cross-linking time. Moreover, increasing the cross-linking time and decreasing the gamma-PGA/beta-TCP weight ratio decreased the swelling ratio and in vitro degradation rate of the composite fibrous mat. In vitro experiments with osteoblast-like MG-63 cells demonstrated that the mat with a gamma-PGA/beta-TCP weight ratio of 20 and cross-linked time of 24 h had a higher alkaline phosphatase activity and better cell adhesion. Furthermore, the rat cranial bone defect was created and treated with the gamma-PGA/beta-TCP composite fibrous mat to evaluate its potential in bone regeneration. After 8 weeks of implantation, micro computed tomography showed that the gamma-PGA/beta-TCP composite fibrous mat promoted new bone growth. These observations suggest that the gamma-PGA/beta-TCP composite fibrous mat has a potential application in bone tissue engineering.