Strontium mineralized silk fibroin porous microcarriers with enhanced osteogenesis as injectable bone tissue engineering vehicles

In this paper, silk fibroin (SF) porous microcarriers containing strontium were constructed as injectable bone tissue engineering vehicles. The effects of SF concentration and strontium content on micromorphology, element distribution, strontium ion release and cellular behavior of the constructed microcarriers were investigated. The microcarriers with an open interconnected pore can be fabricated by controlling the concentration of SF. The strontium functionalized SF microcarriers showed the sustained release of strontium ion and allowed bone mesenchymal stem cells (BMSCs) to attach, proliferate and secrete extracellular matrix. Furthermore, the strontium functionalized SF microcarriers improved the osteogenic capability of BMSCs in vitro compared with those microcarriers without sustained release of strontium ion. This study presents a valuable approach to fabricate polymeric microcarriers with the capability of sustained release of strontium ion that show potential in bone tissue engineering applications. • Strontium loaded injectable microcarriers with an open interconnected pore can be fabricated. • The microcarriers displayed some tailored properties (e.g., morphology, pore size). • The porous microcarriers showed the sustained release of strontium ions. • The released strontium ions can promote the osteogenic differentiation of BMSCs. • The strontium-containing microcarriers have great potential for osteogenesis.