Influence of mechanical microenvironment on the redox state of cardiomyocytes

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 kf 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.

FSCV Update

Did you know that you can perform Fast-Scan Cyclic Voltammetry (FSCV) experiments with your ECP 10 USB Patch Clamp Amplifier or your Potentiostat of the PG Family?

FSCV with potential program in red and resulting current response in blue.

FSCV is used for detecting neurotransmitters, hormones or metabolites in live biological systems. A carbon fiber microelectrode is brought into close proximity to the site under investigation and a potential program is applied. It consists of a rapid triangular potential ramp of 400 V/s to detect the analyte by oxidation or reduction and a wait time at a holding potential between ramps to pre-concentrate the analyte at the microelectrode. The temporal resolution of FSCV is in the range of 100 ms and it has a high selectivity and sensitivity (10 nm LOD dopamine).

FSCV can be combined with other techniques such as fluorescence imaging or patch clamp.

PATCHMASTER and POTMASTER have new features for FSCV with

  • automatic peak detection,
  • automatic background subtraction,
  • synchronized triggers for external stimulus generators.

The potential program can be freely designed in the Pulse Generator File.

Learn more on our FSCV method page.

Contact us if you want to perform FSCV experiments and we will provide you with a FSCV configuration for PATCHMASTER or POTMASTER.

Study of antimicrobial coatings by SECM

The infection of implants poses a common problem. It has been shown that photoactive titanium dioxide coatings can prevent microbial infections by producing free radicals under illumination. Because these free radicals can also damage adjacent cells, it has to ensured that their existence is confined to the implant surface.

The Sant Lab characterized a nitrogen- and self-doped titania coating which produces free hydroxyl radicals upon illumination of the material. Among other characterization techniques the coating was investigated by SECM towards the effects of free radicals on a reducible and oxidizable redox mediator upon irridation in different distances from the coating surface. It could be shown that the existence of free radicals is indeed confined to the vicinity of the surface.

The ElProScan in combination with our acquisition and analysis software POTMASTER allows the creation of complex protocols for automated experiments. The online analysis can display distance-dependent values, e.g. peak currents from a CV while you are still measuring.

Read the paper: