Ag/CNT-PDMS crack sensing for measuring contractility of cardiomyocytes

Measuring myocardial contractility is indispensable for exploring cardiac pathogenesis and quantifying drug efficacy. Among the biosensing platforms developed for detecting the weak contractility of a single layer of cardiomyocytes (CMs), thin brittle metal membrane sensors with micro-cracks are highly sensitive. However, the poor stability limits their application in long-term measurement. Here, we report a high-stability crack sensor fabricated by depositing a 105 nm-thick Ag/Cr with micro-cracks onto a carbon nanotubes-polydimethylsiloxane (CNT-PDMS) layer. This novel brittle-tough bilayer crack sensor achieved high sensitivity (gauge factor: 108,241.7), a wide working range (0.01% - 44%), and high stability (stable period > 2,000,000 cycles under the strain caused by a monolayer of CMs). During 14-day continuously monitoring CMs culturing and drug treatment testing, the device demonstrated high sensitivity and stability to record the dynamic changes caused by contractility of the CMs.