STUDY OF THE RELATIONSHIP BETWEEN EXTRACELLULAR ACIDIFICATION AND CELL VIABILITY BY A SILICON-BASED SENSOR

Based on the existing technology of light addressable potentiometric s ensors we developed a system for measurements of cellular acidificatio n. The system is able to monitor the pH variations. of a micro environ ment where living cells are maintained, fixed on a coverslip; the acqu ired signal is proportional to the acidic products of cell metabolism. Our study is devoted to estimating the limits of acidification for wh ich the viability of mammalian cells is still maintained. As the syste m 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 dam aged, as long as the flow halt situation is maintained, as previously shown. The experiment consists of a set of measurements performed alte rnating flow-on and flow-off steps of increasing time duration. By mea ns of such experiments we also estimated the number of H+ ions derived from the acidic metabolic products secreted by the cells.