Measurement of contractile characteristics from isolated heart cells using a miniaturized force transducer system

Abstract

A custom-designed microelectromechanical force transducer, with a volume less than one cubic millimeter, is being developed to quantify forces generated in isolated, contracting cardiac muscle cells in order to elucidate the physiology of muscle. A single heart cell is attached to flexible, hinged polysilicon plates submerged in a nutrient solution. As the cell contracts, the plates bend, and the contractile force can be measured based on the known spring constant of the plate. The amount of deflection is measured by piezoresistive, ion-implanted strain gauges placed at the base of the plates. Prototype structures have been fabricated and have been mechanically tested using metal probes. The authors have demonstrated that living rat heart cells can be attached to polysilicon using a commercial silicone sealant. They have also observed that polysilicon is an inert material when exposed to cardiac cells and their saline environment and has no detectable effect on the cells themselves.