Photovoltaic recombination sensor as system for real-time determination of lactate dehydrogenase activity

The application of a recombination sensor for real-time detection of Lactate Dehydrogenase (LDH) activities has been demonstrated. LDH activity in biological fluids, particularly in blood serum, is a critical diagnostic indicator of human health. Therefore, the development of methods for monitoring it remains a crucial task in modern bioengineering. The parameter directly measured in real-time is the photocurrent through a deep-barrier structure under light illumination from the region of strong optical absorption in silicon. The detection of enzyme presence can be achieved because the flow of the dehydrogenase reaction (in the presence of LDH activation) is accompanied by changes in charge at the system's interface. Such a change in the effective charge of the reactants can be detected through the amplitude of the sensor structure's photocurrent. The main factor in this approach is the influence on the recombination center parameters at the interface. It has been shown that the combined use of modulated signal illumination and constant illumination allows obtaining additional information about the analyte and reaction kinetics. A promising approach is proposed, which can be considered a simple and sensitive method for real-time detection of lactate dehydrogenase activity.