Inter-connecting pores of chitosan scaffold with basic fibroblast growth factor modulate biological activity on human mesenchymal stem cells

Abstract

► Chitosan (CS) solutions were ultrasonicated to modulate molecular weight of chitosan. ► Interconnecting micropores of scaffolds were observed on the ultrasonicated time. ► Using a LBL method, we prepared heparin immobilized CS scaffolds as depot for bFGF. ► From releasing test, we observed sustained release of bFGF from CS scaffolds. ► The defined pores and bFGF on CS scaffold induced the higher in vitro activity. In this study, we developed bio-active molecules immobilized chitosan scaffolds with controlled pore architectures for enhanced viability of human mesenchymal stem cells (hMSCs). The decreasing in molecular weight of chitosan by ultrasonication of chitosan solution was effective in the formation of porous chitosan scaffolds, resulting in an increase of inter-connecting micropores (∼10 μm) between macropores. Using a layer-by-layer method, we then prepared heparin-coated chitosan scaffolds as depots for basic fibroblast growth factors (bFGF). Enzyme-linked immunosorbent assays confirmed that heparin-coated chitosan scaffolds could bind higher amount of bFGF (24.21 ng/mg) compared to 2.53 ng/mg of non-coated scaffold. Moreover, we were able to manipulate the release profiles of bFGF from the scaffolds for 7 days. In vitro studies showed that chitosan scaffolds induced the improved viability and proliferation of hMSCs through their synergetic effects of the inter-connecting micropores and the sustained released of bFGF. Our results suggest that bFGF immobilized chitosan scaffolds with controlled inter-connecting pores, in combination with other heparin-binding growth factors, have potential implants for controlling biological functions in regenerative medicine.