Oral Presentation 2014 International Biophysics Congress

Coculture stem cells and cardiomyocytes through microsystem technology and study on their electrical coupling (#121)

Qiuying Liu 1 , Zhen Ma 2 , Zhi Gao 2 , Yifei Wang 1
  1. Biomedical R&D Center of Iinan University, Guangzhou, China
  2. Bioengineering, Clemson University, Clemson, SC, USA

To address how the transplanted memsenchycal stem cells interacting with the cardiomyocytes and how they coupling, we used microfabrication techniques to develop different geometrically-defined stem cell-cardiomyocyte contact mode for stem cell-cardiomyocytes cocultured to study on the cell-cell interaction and electrical coupling. Using photolithographic microfabrication and soft lithographic microfabrication to construct several bio-chips made of polydimethylsiloxane (PDMS) with long microwell, which was covered to multielectrode array (MEA) to imitate in vivo cardiomyocytes forming cardio fibers.

The gap was created through some cells absorbed away by the micropipette between the cardio fibers. Certain amount of mesenchymal stem cells, cardiomyocytes and fibroblasts were respectively laser-patterned to form different bridges connecting two separated cardiac muscle fibers inside one microwell. The field potential amplitude(FPA), maximal upstroke velocity(MUV) and field potential duration(FPD) of the mesenchymal stem cells bridge was closed to the cardiomyocytes analyzed by MEA. Carbenoxolone was added to block the gap junctions within cardiac muscle-fiber models with either cardiomyocyte bridges or stem-cell bridges at Day 7, and it was found that this electrical conduction of the cell bridge was reduced concentration depended, and returned to their original levels after they were rinsed. These findings indicated that gap junctions controlled the myocyte-myocyte and stem cell-myocyte electrical couplings. Further, aligned coculture and random coculture biochip was constructed by microsystem technology. The gene expression of GATA4 in aligned coculture was significantly higher than in random coculture analyzed by single cell PCR, and the inward current density was higher and the response time of ion channel was shorter in mesenchymal stem cells in aligned coculture which is close to the cardiomyocytes than in random coculture by patch clamp.