Biosensors Utilizing Non-Michaelis–Menten Kinetics

The action of biosensors utilizing non-Michaelis–Menten kinetics is modeled at mixed enzyme kinetics and diffusion limitation in the cases of substrate and reaction product inhibition as well as of allostery at steady state and transient conditions. Computational modeling of the substrate inhibition at steady state shows multi-steady state concentrations of the substrate at the surface of the enzyme layer (membrane) when the diffusion module is much larger than one and the substrate bulk concentration is much higher than Michaelis–Menten constant. The multi-steady state concentration generates multi-response of the biosensor. At transient conditions, analytical systems are modeled by a two-compartment model comprising a mono-enzyme layer and an external Nernst diffusion layer. The complex enzyme kinetics produces different calibration curves for the response at the transition and the steady state. The cooperative phenomena of allosteric enzymes are modeled by applying the substrate uptake and the Hill equations. The positive cooperativity leads to a steady state current less than that when the biosensor action obeys the Michaelis–Menten kinetics, while negative cooperativity leads to increasing the biosensor response. The substrate concentration, at which the saturation curves of allosteric biosensors intersect, increases with increasing the external diffusion limitation.