Bioactive Macro/Micro Porous Silk Fibroin/Nano-Sized Calcium Phosphate Scaffolds with Potential for Bone-Tissue-Engineering Applications

Abstract

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-tissue-engineering applications.

Original submitted 21 December 2011; Revised submitted 10 July 2012; Published online 24 December 2012

Keywords::

• bone tissue engineering
• nano-sized calcium phosphate
• nanocomposite
• porous scaffold
• silk fibroin

Financial & competing interests disclosure

This study was funded by the Portuguese Foundation for Science and Technology (FCT) through the projects Tissue2Tissue (PTDC/CTM/105703/2008) and OsteoCart (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 (SFRH/BD/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.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Acknowledgements

The authors thank Dr RA Pires for his kind help in FTIR analysis.

Additional information

Funding

This study was funded by the Portuguese Foundation for Science and Technology (FCT) through the projects Tissue2Tissue (PTDC/CTM/105703/2008) and OsteoCart (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 (SFRH/BD/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.