Publisher Summary The detection of analytes involved in physiological cellular reactions is an important area of investigation of biosensor applications. This chapter analyzes examples of physiological cellular reaction detection on biosensor surfaces and discusses their kinetics. Fractal analysis is used to analyze the binding and dissociation (if applicable) kinetics for the binding and dissociation of different concentrations of bradykinin to a bradykinin B2 receptor on a RWG biosensor, the binding and dissociation of mβCD cholesterol to HeLa cells cultivated on a gold-plated prism, and the binding and dissociation (if applicable) of calcium + FRET-based calcium biosensor employing troponin for the binding and dissociation of TXNL in solution to the sensor-chip surface. Both single- and dual-fractal analyses have been used in the analysis. The dual-fractal analysis was used only when the single-fractal analyses did not provide an adequate fit. The fractal dimension provides a quantitative measure of the degree of heterogeneity present on the biosensor chip surface. The fractal dimension for the binding and dissociation phase, Df and Dfd, respectively, is not a typical independent variable, such as analyte concentration, that can be directly manipulated. An increase in the fractal dimension value or the degree of heterogeneity on the biosensor surface leads, in general, to an increase in the binding rate coefficient. More such studies are required to determine whether the binding and dissociation rate coefficient(s), and subsequently the affinity values are sensitive to their fractal dimensions present on the biosensor surface with regard to these types of reactions.