Changes in microstructure and physico-chemical properties of hydroxyapatite–silk fibroin nanocomposite with varying silk fibroin content

Hydroxyapatite (HAp)–silk fibroin (SF) nanocomposites with various HAp/SF weight ratios were synthesized by a co-precipitation method. We examined the effects of SF content on the microstructure and physico-chemical properties of the composites. Growth of HAp crystallites in both directions, i.e. along the c- and a-axes, was suppressed by the introduction of SF. With SF content increased up to 40 wt.%, the particle size distribution became narrower and the Vickers microhardness of the composites increased by a factor of 4. The composites exhibited the porous microstructure with open porosity around 62–74%. About 70% of the interconnective pores were between 40 and 115 μm in diameter. Among all the as-prepared samples, the composite containing 30 wt.% of SF showed the most homogeneous particle form and a well dispersed state of HAp crystallites together with a highly developed three-dimensional network.