MATHEMATICAL MODEL OF THE DEPENDENCE OF THE ZETA POTENTIAL OF HUMAN SERUM ALBUMIN ON THE pH OF THE SALINE

Source abstract

Introduction. The article is devoted to the construction of a mathematical model of zeta potential dependence of the human serum albumin macromolecule of in a 0.15 M aqueous solution of sodium chloride (saline) as a function of the pH change (acid-base balance) of the aqueous environment. Methods. The asymmetry of the specified experimental dependence relative to the isoelectric point of albumin pH0 5.1, at which the zeta potential of the macromolecule equals zero, was analyzed. Results. A mathematical model is proposed, which provides division of the dependence of the zeta potential of the human serum albumin macromolecule in saline as a pH function into two intervals: 1) in the range of pH < pH0, an exponential function is used for approximation; 2) in the range of pH > pH0, the experimental dependence is approximated by the hyperbolic tangent function. Within the experimental error, the zeta potential values calculated using the proposed mathematical model correlate well with the experimental values: the average relative error is estimated to be less than 5.5 % at pH < pH0 and did not exceed 4.1 % at pH > pH0. Conclusions. The obtained results can be used to create a physical model that relates the spatial structure and electrophysical properties of the albumin macromolecule when the pH of the solution changes.