A contractile force measurement system for hiPSC-derived cardiac tissue integrated with an ultrathin, stretchable nanomesh

Abstract

Mechanical stretch is a vital factor influencing the structural and functional properties of cardiac tissue, including its contractile force. While various platforms using elastic substrates have been developed to measure contractile force under mechanical stretch in real-time, significant challenges remain, such as achieving mechanical stability, maintaining sustained cell adhesion, and ensuring seamless system integration. In this study, we developed a contractile force measurement system for hiPSC-derived cardiac tissue using an ultrathin, stretchable polyurethane nanomesh substrate that addresses these limitations. The porous, fibrous structure of the nanomesh provides high mechanical compliance and stretchability, effectively serving as a biomimetic elastic substrate for the cardiac tissue. Furthermore, the structure facilitates mechanical interlocking with the tissue, demonstrating significantly more sustained cell adhesion compared to a flat substrate. Using this system, we successfully demonstrated stretch-dependent increases in contractile force, a phenomenon central to the Frank–Starling mechanism, and significant stretch-dependent differences in pharmacological responses. Our results suggest that this system serves as a valuable platform for investigating cardiac function and pharmacological responses under mechanical stretch in vitro.