Integration of a Micro-Transparent heater-integrated electrochemical (μTHE) cell for investigation of the thermal stability of cytochrome c redox variants

Spectroelectrochemistry (SEC) is a powerful technique that combines spectroscopic and electrochemical properties to investigate the redox potential and spectral characterization of chemical or biological molecules. Recently, SEC has gained attention in quantitative analysis, particularly in exploring the role of redox-active proteins in electron transfer networks related to biological systems. The microfluidic technique is used to investigate the spectroelectrochemical properties of the redox potential of metalloproteins under accurate temperature environments. However, conventional heater systems suffer from long ramping times and the transparency of heat systems would influence the spectroscopic information. In this study, we fabricated a micro-transparent heater-integrated electrochemical (μTHE) cell. The μTHE cell allows for spectroelectrochemical studies to investigate the thermal stability of cytochrome c at specific temperatures and the transparent ITO heater integrated into the μTHE cell offers rapid and accurate temperature control during the measurements, avoiding interference with spectroscopic information. The μTHE cell could regulate the oxidation/reduction forms of cytochrome c by the electrochemical process, and the ITO heater provides the precise temperature control for the observation of the absorption spectrum of cytochrome c at different temperatures. By taking advantage of rapid heating and transparency, the μTHE cell offers a facile platform for investigating the spectroelectrochemical properties of redox-active molecules in a well-controlled environment.