High-resolution microsphere sensor for monitoring the spatial mechanical beating of cardiomyocytes in high-noise multi-scene environments

Advanced measurement methods are critical for quantifying spatial systole and diastole of cardiomyocytes in heart disease research. However, restricted by traditional microscopic observation and measurement methods, current research on the kinetics of a single cardiomyocyte mainly focuses on the focal plane of the utilized microscope. This paper proposes a novel, non-invasive, multi-point, and high-resolution three dimensional (3D) measuring method based on microsphere tracking, which can be used to analyze the mechanical beating of cardiomyocytes at a single-cell level. An expansion rotation method was proposed to analyze off-focus imaging informatics for characterizing the contractile motion of a single cardiomyocyte, obviating the need for costly and complex equipment to monitor cardiomyocytes’ mechanical beating activity. Furthermore, to the best of our knowledge, a 3D beating curve of a single cardiomyocyte was drawn for the first time, and the actual spatial movement states of cardiomyocytes in different scenarios were recorded. The applicability of the motion characterization method was tested to determine the pharmacological effects of a typical cardiovascular drug, isoprenaline (1 μM and 5 μM). Within 18 days, the 3D beating curves indicated that the motion of cardiomyocytes tends to be smooth and regular during maturation. The findings offer insights into the contractile motion of single cardiomyocytes and a deep understanding of their kinetics at a single-cell level for multiple scenarios.