Fabrication and in vitro characterization of electrospun poly (γ-glutamic acid)-silica hybrid scaffolds for bone regeneration.

To mimic the structure and composition of the natural bone extracellular matrix (ECM), fibrous hybrid scaffolds were prepared by electrospinning a sol–gel derived mixture of poly(γ-glutamic acid) (γ-PGA) and hydrolyzed tetraethylorthosilicate (TEOS). The introduction of NaHCO 3 caused the formation of the sodium salt form of γ-PGA, making the polymer soluble in aqueous-based solution. To improve the stability of electrospun γ-PGA-silica hybrid scaffolds under physiological environment, 3-glycidoxypropyl trimethoxysilane (GPTMS) was employed as a coupling agent to link γ-PGA and silanols of the hydrolyzed TEOS. The effect of the TEOS content on the physicochemical properties of the electrospun hybrid scaffolds, such as morphology, microstructure, mechanical behavior, degradation, as well as in vitro biocompatibility were investigated. The resultant fibers revealed a uniform morphology with the increased mean diameter as the content of TEOS increased. The results of FTIR and 29 Si MAS-NMR indicated that γ-PGA and silica networks were successfully covalent-linked in the presence of GPTMS. All of these electrospun hybrid scaffolds showed stable soluble silica release without any initial burst release in Tris–HCl buffer solution and the content of released silicon can also be adjusted by the TEOS content. In addition, the tensile mechanical performances, thermal stability, and in vitro proliferation and ALP activity of fibrous scaffolds were effectively improved by the increasing TEOS content. The results suggest that the γ-PGA-silica hybrid scaffolds with tailorable physiochemical properties can provide an excellent ECM for bone tissue regeneration. [ABSTRACT FROM AUTHOR]