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

► 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.