Diatom Particles: A Promising Osteoinductive Agent of Silk Fibroin-Based Scaffold for Bone Regeneration

Abstract

The regeneration of bone tissue via tissue engineering procedures is a challenging task that requires the selection of materials/scaffolds, with tailored biological and physical properties, and possibly the use of osteogenic additives that can stimulate cells to produce and mineralize collagen. Apart from growth factors, whose use is restricted by their high cost, inorganic compounds, such as calcium phosphates or silicates, have demonstrated intrinsic ability to facilitate the collagen mineralization and to address the differentiation of cells towards osteoblast lineage. Silicon, in particular, is considered to have a great relevance in the early stages of bone formation. In the past, we investigated the use of silk fibroin scaffolds, in form of sponges or gels, for bone tissue engineering. In this paper we have combined silk fibroin with diatoms, that are silica-based organisms, and we have evaluated the biological response of human mesenchymal stem cells (hMSCs) cultured on diatom loaded fibroin sponges. We found proofs of the improved osteogenic activity of the diatoms loaded scaffolds in the increase of alkaline phosphatase activity (ALP) and in the early fibronectin and collagen type I formation.