Fluid actuation for a bio-micropump powered by previously frozen cardiomyocytes directly seeded on a diagonally stretched thin membrane

Recently, various microfluidic devices have been developed. However, they are difficult to use in vivo because they require an external energy source such as electricity. Taking a different approach, we previously developed a bio-micropump powered by cardiomyocyte sheets that utilizes only glucose in the medium as chemical energy (Tanaka et al., Lab Chip 6(3), 362-368) [5]. To fabricate the pump, we require fresh primary neonatal rat cardiomyocytes. This operation is complicated and inconvenient because the experiments can only be carried out when rats are obtained. If commercially available frozen cardiomyocytes could be used, the experiments would become easier because frozen cells can be thawed and used any time. One technical problem with this new approach is that the force generated by thawed frozen cardiomyocytes is weak and it is difficult to fabricate a contiguous cell sheet using them. In the present study, we report that we have developed an actuator for fluid actuation for a bio-micropump using thawed frozen cardiomyocytes having a new structure, by using a thin membrane and a cubic block to collect the cardiomyocyte force and communicate it to fluid. We were able to demonstrate fluid motion in a microchannel connected to a diaphragm chamber induced by the synchronously pulsating cardiomyocytes. This new approach reduces the necessity of using animals for the experiments, because frozen cells may be used.