A visual detection method of cardiomyocyte relaxation and contraction

Contraction and relaxation are important functions of cardiomyocytes, and measuring their characteristics provides an evaluation index to explore the effects of drugs on cardiomyocytes. In addition, cardiomyocytes have an innate advantage in acting as a biopower by virtue of their ability to contract and relax, which also requires the detection of cardiomyocyte actions. However, existing measurement methods, such as mechanosensor measurements and calcium concentration measurements, have high requirements for experimental equipment and operation and are challenging to perform simultaneously with other cellular manipulations. Here, we propose a simple visual detection method for cardiomyocyte contraction and relaxation. We first recorded the contraction and relaxation of cardiomyocytes under a bright-field microscope, then used the optical flow method to track the sampling points on the cardiomyocytes in the video, and obtained the frequency of cardiomyocyte contraction and relaxation by analyzing the optical flow matrices. This method does not require the use of additional equipment or additional processing of cardiomyocytes, which significantly reduces the operational difficulty of detection and provides a method to achieve real-time detection of cardiomyocyte contraction and relaxation.