Fabrication of biocomposite sheets from silk cocoons for tissue engineering applications

Silk based biomaterials have been explored as a natural-based system for tissue regeneration. Biocomposite sheets were fabricated by controlled deposition of hydroxyapatite (HA) on porous silk cocoon structure through precipitation method using calcium chloride dihydrate and disodium hydrogen phosphate anhydrous solutions. The formation of hydroxyapatite coating on the silk sheets was confirmed by the presence of characteristic apatite peaks in the XRD patterns. The interactions between HA and silk proteins were evidenced by a shift in the amide peaks of biocomposites as observed from the IR spectra. The mineralisation of silk sheets did not alter their thermal stability as revealed from the thermogravimetric analysis. Scanning electron microscopy of the silk sheets showed the growth of hydroxyapatite on the surface of fibrous silk networks. The tensile strength of the biocomposite sheets is decreased to 21-30 MPa when compared to native silk sheets that had 32 MPa. The properties of silk cocoon-hydroxyapatite biocomposite sheets indicate its potential as a suitable substrate for bone tissue engineering application.