Preparation And Characterization Of A Non-Woven Beta-Tricalcium/Collagen Composite Scaffold

A non-woven beta-tricalcium phosphates(β-TCP)/collagen scaffold was fabricated by sol-gel electrospinning and impregnating methods. Firstly,raw calcium phosphates(CAP) powders were synthesized from triethyl phosphate(TEP) and calcium nitrate via sol-gel method.The effects of initial calcium/phosphate(Ca/P) molar ratio,catalyst and heat treatment temperature on the structural evolution of CaP were investigated by using X-ray diffraction(XRD),infrared spectrometry(IR), X-ray fluorescence spectroscopy(XRF),and combined thermogravimetry-differential thermal analysis(TG-DTA).The crystalline phases of heat-treated powders changed from hydroxyapatite(HA) to tricalcium phosphate(β-TCP) and calcium pyrophosphate(CPPD) with the decrease of Ca/P ratio from 1.5 to 1.0.Secondly,the TEP/Calcium nitrate[Ca(NO₃)₂]Sol blending with 5 wt.%polyvinylpyrrolidone(PVP) was electrospun and then heat-treated at 1100℃in air to form pureβ-TCP fibers with diameters ranged from hundreds to thousands nanometers.Finally,collagen coating was formed on the surface of β-TCP fibers by impregnating and lyophilizing methods,to improve the biocompatibility and stability of the ceramic scaffolds.The morphologies of fibers and composites were observed by scanning electron microscope (SEM) and the components were determined by TG analysis.The resultantβ-TCP scaffold andβ-TCP/collagen composite underwent a high rate of dissolution and new apatite formation in phosphate buffered saline (PBS) solution.Numerous needle-like apatite crystals were deposited on the surface of fibers of the pureβ-TCP scaffold after it being soaked in PBS for 2 weeks,while platelet-shaped apatite crystals with larger size were observed on theβ-TCP/collagen composite scaffold.After 4 weeks, 38%of theβ-TCP scaffold and 46%of theβ-TCP/collagen scaffold were degraded in PBS solution,respectively.The co-culture of MG-63 on the non-wovenβ-TCP andβ-TCP/collagen scaffolds in vitro showed that the scaffolds with non-woven structure could provide three-dimensional(3D) supports for the extensive in-growth of cells.These results suggest that the non-wovenβ-TCP/collagen scaffold was capable of improving bone regeneration by providing enhanced mineralization and cell infiltration.