Cell biothermodynamics: Can calorimetry dynamically monitor cytoplasmic water activity?

In this study, the isothermal dehydration of some biological substrates, i.e., cell monolayer, has been explored as an extension of the novel application of DSC for monitoring the dehydration changes in aqueous films of polysaccharide solutions and gels. Here we assess the possible correlation of the experimental calorimetric signal (heat flow) and changes in the water binding state using unperturbed or stressed cells as treated using hypotonic solutions or AgNO3 as aquaporin inhibitors. The experiments on unperturbed and stressed cells show the requirement for a proper setup in order to obtain reproducibility to highlight the cell dehydration patterns. The preliminary results and the analysis of the calorimetric curves proved the feasibility of the described measurements on cellular substrates and revealed a good sensitivity of the experimental response on the specific features of the system and on its actual hydration state.