Combinatorial Effect of Silicon and Calcium Release from Starch-Based Scaffolds on Osteogenic Differentiation of Human Adipose Stem Cells

Instructive materials able to drive cells, in particular the differentiation of stem cells toward osteoblastic lineages, have been investigated as a promising strategy for bone tissue engineering. Inorganic ions, such as phosphorus, calcium, silicon, and strontium, have been used in bone regeneration strategies as instructive ions for material-based approaches. The use of effective inorganic ions is being investigated as a promising approach for bone regeneration applications, mainly because they are highly available and cost-effective and thus reducing the need to use expensive and less-stable growth factors. The aim of the present study is to investigate the effect of the release of silicon (Si) and calcium (Ca) ions from a blend of starch and poly caprolactone (SPCL) scaffolds on the osteogenic behavior of human adipose stem cells (hASCs). The scaffolds were developed by a wet-spinning technique and two different solutions were used as coagulation bath, one containing Ca and Si ions and other one containing only Si ions. The composition of the scaffolds as well as their mechanical properties was also evaluated. Our study showed that both scaffolds were able to sustain cell attachment and induce their differentiation into the osteogenic lineage in basal medium, i.e., in the absence of osteogenic factors. The scaffolds containing both ions, Si and Ca, had a stronger influence on the osteogenic differentiation of hASCs than the scaffolds containing only Si ion. Thus, the present work highlights the importance of combining Si and Ca ions in the control of cellular response, namely, cell differentiation and/or in stem cells recruitment upon implantation of a cell-free scaffold, and thus, avoiding the use of costly growth factors.