SECM

The regulation of intracellular redox microenvironment is of immense importance for the homeostasis of cells. The mechanical microenvironment plays a key role in the regulation of the phenotype and function of cardiac cells, which are strongly associated with the intracellular redox mechanism of cardiomyocytes. Glutathione (GSH) is the most abundant intracellular nonprotein thiol and functions as one of the most important endogenous antioxidants in cells. Under normal physiological conditions, intracellular chemical microenvironment is maintained in a relatively reduced state due to a higher GSH concentration than that of glutathione disulfide (GSSG). the relationship between the redox state of cardiomyocytes and their mechanical microenvironment remains elusive.

The Li Lab at the BEBC at Xi’an Jiaotong University investigated the influence of the mechanical microenvironment on the redox state of single cardiomyocytes in situ by SECM. The redox state was studied by quantifying the GSH level of living cardiomyocytes at single-cell level. Different mechanical microenvironments were simulated using polyacrylamide (PA) gels of different stiffness as the substrate. SECM depth scans were recorded and aprroach curves extracted to obtain rate constants k_f for the reaction of the redox mediator FcCOOH and GSH which are a direct measure of GSH levels.

Li, Y., Lang, J., Ye, Z., Wang, M., Yang, Y., Guo, X., Zhuang, J., Zhang, J., Xu, F. and Li, F. (2020) ‘Effect of Substrate Stiffness on Redox State of Single Cardiomyocyte: A Scanning Electrochemical Microscopy Study’, Analytical Chemistry.

It was shown that stiffer substrates induce a more oxidative state of the cardiomyocytes compared to the softer substrates. This result can contribute to understand the effect of mechanical factors on the cell’s redox mechanism, such as the myocardial fibrosis caused overaccumulation of ECM.

SECM proved to be a sensitive, label-free and in situ technique for the investigation of redox state in single-cells.

HEKA’s ElProScan ELP 3 provides the ideal conditions for working with live single cells. The inverted microscope allows visual control of the cells and exact positioning of the microelectrode and a range of heated stages for working under physiological conditions. The unique depth scan allows the study of concentration profiles above single cells.