Analysis of the Influence of Competitive Adsorption and Mass Transfer on Adsorbed Mass Fluctuations in Affinity-Based Biosensors

Abstract

We analyze the fluctuations of the equilibrium adsorbed mass in affinity-based biosensors, caused by both the random nature of adsorption-desorption and mass transfer processes of two molecular species (the target and the competitor molecules) which bind to the probe molecules. The analytical expression for the fluctuations spectral density is derived. The calculations show the significant influence of both the competitive adsorption and the mass transfer on the fluctuations spectrum. The theory provides a more realistic estimation of limiting performance of biosensors, and is useful for their improvement.