Piezoresistive sensor-integrated PDMS cantilever: A new class of device for measuring the drug-induced changes in the mechanical activity of cardiomyocytes

- This article proposes a strain sensor-integrated PDMS cantilever for measuring the drug induced changes in the mechanical activity of cardiomyocytes.
- Integration of the strain sensor eliminate the use of an external optical measurement system.
- Electrical reliability of the sensor is greatly improved by using a glass body with metal patterns.
- Microgrooves formed on the PDMS cantilever effectively align the cardiomyocytes and maximize their contraction force.
- The cantilever deflection caused by the contraction force of the cardiomyocytes is successfully measured using the integrated strain sensor in real time.

Herein, we demonstrate in detail the fabrication and evaluation procedure of a piezoresistive sensor-integrated polydimethylsiloxane (PDMS) cantilever for measuring the drug-induced changes in the contraction force of cardiomyocytes. The proposed device consists of a glass body with metal patterns, a PDMS cantilever with microgrooves (μgrooves), and integrated piezoresistive sensor. Reliability of the piezoresistive sensor and connection wires was greatly improved by using a glass substrate with metal patterns. The longitudinally patterned μgrooves formed on the PDMS cantilever was optimized to maximize cantilever deformation. The mechanical deformation of the cantilever caused by the contraction force of cardiomyocytes is directly observed by using the integrated piezoresistive sensor, whereas the existing methods rely on the optical methods to measure the cantilever displacement. The contraction force is maximized between day eight and nine after seeding the cardiomyocytes onto the PDMS cantilever. After preliminary experiments, the strain sensor integrated μpatterned PDMS cantilever was subjected to measure the change in the contraction force of cardiomyocytes under different concentrations of cardiac drugs. The experimental results showed that the strain sensor integrated PDMS cantilever can effectively verify the changes in the mechanical output of the cardiomyocytes under the drug influence.