Bioactive macro/micro porous silk fibroin/Nano-sized calcium phosphate scaffolds with potential for bone tissue engineering applications

Aim: The development of novel silk/nano-sized calcium phosphate (silk/nano-CaP) scaffolds with highly dispersed CaP nanoparticles in the silk fibroin (SF) matrix for bone tissue engineering. Materials & methods: Nano-CaP was incorporated in a concentrated aqueous SF solution (16 wt.%) by using an in situ synthesis method. The silk/nano-CaP scaffolds were then prepared through a combination of salt-leaching/ lyophilization approaches. Results: The CaP particles presented good affinity to SF and their size was inferior to 200 nm when theoretical CaP/silk ratios were between 4 and 16 wt.%, as determined by scanning electron microscopy. The CaP particles displayed a uniform distribution in the scaffolds at both microscopic and macroscopic scales as observed by backscattered scanning electron microscopy and micro-computed tomography, respectively. The prepared scaffolds presented self-mineralization capability and no cytotoxicity confirmed by in vitro bioactivity tests and cell viability assays, respectively. Conclusion: These results indicated that the produced silk/nano-CaP scaffolds could be suitable candidates for bone-tissueengineering applications.This study was funded by the Portuguese Foundation for Science and Technology (FCT) through the projects Tissue2Tissue (PTDC/CTM/105703/2008) and Osteo Cart (PTDC/CTM-BPC/115977/2009). The funding from Foundation Luso-Americana is greatly acknowledged. L-P Yan gives thanks for his PhD scholarship from FCT (SFRHIBD/64717/2009). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or potions, expert testimony, grants or patents received or pending, or royalties