In vivo biological responses to silk proteins functionalized with bone sialoprotein.

Recombinant 6mer + BSP protein, combining six repeats of the consensus sequence for Nephila clavipes dragline (6mer) and bone sialoprotein sequence (BSP), shows good support for cell viability and induces the nucleation of hydroxyapatite and tricalcium phosphate during osteoblast in vitro culture. The present study is conducted to characterize this bioengineered protein-based biomaterial further for in vivo behavior related to biocompatibility. 6mer + BSP protein films are implanted in subcutaneous pouches in the back of mice and responses are evaluated by flow cytometry and histology. The results show no major differences between the inflammatory responses induced by 6mer + BSP films and the responses observed for the controls. Thus, this new chimeric protein could represent an alternative for bone regeneration applications.