N-Acetyl cysteine (NAC)-mediated reinforcement of alpha-tricalcium phosphate/silk fibroin (α-TCP/SF) cement

Calcium phosphate cements (CPCs) are popular bone filling materials and drug carriers. However poor mechanical properties and lack of osteoinduction restrict their clinical applications. Recent studies suggested the osteogenic properties of NAC. In our study, we incorporated NAC with alpha-TCP/SF. We found that the compressive strength of alpha-TCP/SF-NAC composites increased with increase in NAC concentration, possibly due to complex three-dimensional networks of SF induced by NAC, which was large and chemically heterogeneous and induced compact oriented growth of HA crystals. However the setting time increased slightly with the addition of NAC, due to the ruptured disulfide bonds in SF. The alpha-TCP/SF-NAC composites also showed decent biocompatibility in vitro. As a result, these composites hold great potential as bone filling materials for clinical applications, including minimally invasive surgeries. (C) 2015 Elsevier B.V. All rights reserved.