Abstract 3458: Electrical Stimulation of Mesenchymal Stem Cells in the Presence of Carbon Nanotubes
At present, there is no effective clinical therapy available for the repair of damaged cardiac muscle, thereby presenting tremendous opportunities for the creation of novel nanotechnology based therapies. To date, very little is known about the effects of carbon nanotubes (CNT) on stem cells. These electrically conductive nano biomaterials offer great potential for the manipulation of mesenchymal stem cells (MSC) differentiation pathways to create electroactive cells such as those found in the heart. This study aims to test the hypothesis that MSC electrically stimulated in the presence of CNT will differentiate towards a cardiomyocyte lineage. In this study, human MSC (hMSC) were isolated from human bone marrow and their multipotency confirmed by differentiation to the adipogenic, osteogenic and chondrogenic lineages. Upon confirmation that the CNT had no adverse effect on MSC proliferation or multipotency, a CNT tracking study was conducted to investigate the uptake of CNT by the cells. In brief, hMSC were exposed to 0.032mg/ml of COOH-functionalized SWNT for 24hrs. Using fluorescence microscopy, after 24 hrs the CNT were seen to migrate through the cell wall and after 6 days a significant number of the labeled nanotubes assumed a nuclear location, thereby providing the opportunity for in situ electrical stimulation of the cells. As a consequence, the hMSC containing CNT were electrically stimulated in an electrophysiological bioreactor with a rectangular pulse, at a frequency of 1 Hz, with a 2ms duration and an amplitude of 5 V/cm over a 10 day period and fed every 3– 4 days. As a method of control, hMSC were electrically stimulated in the absence of CNT. Differentiation towards the cardiomyocyte phenotype was assessed by immunostaining with cardiac myosin heavy chain and α-sarcomeric actin; DAPI was used as a nuclear stain. After stimulation, results indicated that the hMSC aligned perpendicular to the direction of the current. Furthermore, the hMSC electrically stimulated in the presence of the CNT stained positive for cardiac markers. Thereby, highlighting the promise of the synergy between nanotechnology and stem cell science for the development of novel cardiac repair therapies.