Development of macro/micro porous silk fibroin scaffolds with nano-sized calcium phosphate particles for bone tissue engineering

摘要

Macro/micro porous silk scaffolds with nano-sized calcium phosphate(CaP) particles were developed for bone tissue engineering. Differentamounts of nano-sized CaP particles 4, 8, 16 and 25% (CaP:silkfibroin, wt/wt) were generated into the highly concentrated aqueoussilk fibroin solutions via an in-situ approach. Afterwards, the puresilk and silk/nano-CaP porous scaffolds were produced by a combinationof salt-leaching/freeze-drying methods. Thermal gravimetricanalysis results were able to demonstrated that the silk/nano-CaPscaffolds maintained 64–87% of incorporated CaP after salt-leaching.Dynamic mechanical analysis showed that storage modulus of the16% formulation was significantly higher than all remaining groups.The porosity of silk/nano-CaP scaffolds assessed using Micro-ComputedTomography decreased from 79.8% to 63.6% with increasingCaP incorporated until 16%. By soaking the scaffolds in SimulatedBody Fluid for 7 days, cauliflower-like apatite clusters were observedon the surface of both macro and micro pores of 16% and 25% formulations,which was not observed in 4 and 8% formulations. 16%silk/nano-CaP scaffolds were further chosen for in vitro cytotoxicityand biocompatibility assays. Both silk and 16% silk/nano-CaP scaffoldswere non-cytotoxic and promoted cell adhesion and proliferationto a similar extent. These results indicated that the 16% silk/nano-CaP scaffolds could be a good candidate for bone tissueengineering.