Development of a model based on reaction-diffusion equations for the estimation of intracellular Ca2+ concentration

Ca2+ ions are vital for several functions in the human body such as muscle contraction, neuronal communication, fertilization and gene transcription. The estimation of Ca2+ concentration in living cell is thus a key point in biophysical research. This thesis work is conceived to derive and validate a novel mathematical formula that, based on experimental data obtained by fluorescent Ca2+ dyes, overcomes the general approximation that Ca2+ is in equilibrium with its reactants, even in the presence of a rapid Ca2+ influx, e.g. during neuronal depolarization. Our formula, which permits to derive the intracellular Ca2+ concentration from dye fluorescence recordings and a few experimental parameters, was validated by a numerical simulation in the Matlab framework based on reaction-diffusion differential equations. At present, we are performing Ca2+ imaging experiments on HeLa cells by the UV-flash photolysis technique to obtain an experimental validation of our model. The biological target of our study would be to use the new formula to obtain a more accurate description of Ca2+ nanodomains that control neuronal activity.