An essential component of this type of device is the micropump. Currently, microdevice applications are limited because these pumps are typically powered by external energy sources like batteries, making it difficult to really miniaturize them down to the “micro” level. However, a recent publication by an international joint research team led by Nobuyuki Tanaka and Yo Tanaka at the RIKEN BDR reported the fabrication of the world’s smallest autonomous hybrid pump. This micropump, made from a silicon-based organic polymer called polydimethylsiloxane (PDMS), is powered by cardiomyocytes (heart muscle cells) that self-organize into muscle tissue forming a cardiomyocyte bridge on the elastic PDMS microstructure.

How did they do it?

The team at BDR cultured rat cardiomyocytes on PDMS sheets with micro-grooves. They found that the cells spontaneously formed a three-dimensional pulsatile tissue that bridged the gaps between the grooves. Experiments showed that the highest number of bridges formed when the distance between grooves was 200 micrometers (0.2 mm). This is important because more bridges means more force is generated when the tissue contracts.