Study of the relationship between extracellular acidification and cell viability by a silicon-based sensor

Abstract Based on the existing technology of light addressable potentiometric sensors we developed a system for measurements of cellular acidification. The system is able to monitor the pH variations of a micro environment where living cells are maintained, fixed on a coverslip; the acquired signal is proportional to the acidic products of cell metabolism. Our study is devoted to estimating the limits of acidification for which the viability of mammalian cells is still maintained. As the system basically consists of a micro volume flow chamber, it is possible to continuously refresh the cell medium, or to stop the flow, so causing acidic metabolites to build up. In a flow-off condition cells are damaged, as long as the flow halt situation is maintained, as previously shown. The experiment consists of a set of measurements performed alternating flow-on and flow-off steps of increasing time duration. By means of such experiments we also estimated the number of H + ions derived from the acidic metabolic products secreted by the cells.