Synergy of substrate conductivity and intermittent electrical stimulation towards osteogenic differentiation of human mesenchymal stem cells.

Human Mesenchymal Stem cells (hMSCs) have the unique potential to differentiate into multiple cell types. Depending on the cellular microenvironment (physical and biochemical cues), hMSCs can be directed to differentiate into osteogenic, chondrogenic, myogenic and adipogenic lineages. Among the strategies available to direct stem cell fate processes, electrical stimulation based approach has been extensively investigated in recent studies. In the present study, the conducting Hydroxyapatite-CaTiO3 (HA-CT) composites are used as electroconductive platforms to support the differentiation of hMSCs, in vitro. During culture without osteogenic supplements, intermittent electrical stimulation is provided every 24h over a period of 4weeks through parallel plate electrodes separated by a distance of 15mm and maintained at a static potential of 15V for 10min. In addition to cell morphological changes, the differentiation behavior of hMSCs after electrical stimulation is evaluated by mRNA expression analysis through polymerase chain reaction (PCR). Importantly, specific bone markers, in particular ALP, Col IA and Osteocalcin are expressed more significantly due to electrical stimulation, which also enhances the extent of extracellular matrix mineralization. Taken together, this study establishes the effectiveness of electroconductive HA-CT composites together with intermittent electrical stimulation to direct osteogenesis of hMSCs.