Enhancement of surface adsorption-desorption rates in microarrays invoking surface charge heterogeneity

Abstract

This investigation is devoted to the influences of non-uniform wall characteristics on the surface adsorptiondesorption rates in an electrokinetic microarray.Utilizing already explored electroosmotic and electrophoretic velocities, the species transport equations are solved by a finite-volume-based numerical approach.Uniform, sinusoidal, and pulse-like distributions of the zeta potential are considered in the analysis. The developed model is validated by comparing the results with those of two analytical solutions that are derived for limiting conditions. The results reveal that, in some cases,the surface chargeheterogeneity can reducethe saturation time by more than 60%.The efficacy of the surface chargeheterogeneity is limited to high Damkohler numbers and its effects are negligible for small values of this parameter. Whereas the impact of non-uniform surface characteristics is amplified by increasing the Peclet number, it is reduced by increasing either of the channel length to radius ratio or the electrophoretic mobility of the analytes.

Unsteady solute dispersion by electrokinetic flow in a polyelectrolyte layer-grafted rectangular microchannel with wall absorption

“…One important issue scientists are trying to resolve regarding these devices is their long hybridization time. If the inner layer of DNA microarrays is coated with long polyelectrolyte brushes, the consequent increase in dispersivity can lead to a faster movement of targets toward the downstream, where binding sites are located, thereby accelerating the hybridization process (Abdollahzadeh, Saidi & Sadeghi 2017). Figure 15 shows the effect of the PEL friction factor α on the dispersion coefficient.…”

Analytical solutions for reactive shear dispersion with boundary adsorption and desorption

“…As a general case for arbitrary initial conditions, the eigenvalue problem may depend on the azimuthal angle, and Bessel functions of higher orders may need to be considered. In addition, our simple analytical procedure can be conveniently applied to reactive transport problems in laminar or turbulent flows (Ng & Yip 2001), natural streams (Valentine & Wood 1977;Sandoval et al 2019;Wu et al 2021), wetland flows (Yang et al 2020;Guan et al 2021), electroosmotic flows (Abdollahzadeh, Saidi & Sadeghi 2017;Mederos et al 2020;Sadeghi et al 2020;Sivasankar et al 2021), oscillatory flows (Ng 2006;Paul & Mazumder 2011;Mazumder & Paul 2012;Debnath et al 2019;Mederos et al 2020), etc. These applications are of practical interest in chemistry, biology and hydraulic engineering.…”

“…2020; Guan et al. 2021), electroosmotic flows (Abdollahzadeh, Saidi & Sadeghi 2017; Mederos et al. 2020; Sadeghi et al.…”

Regulating Biomolecular Surface Interactions Using Tunable Acoustic Streaming

“…Many efforts have been made to improve the analyte’s transport – by applying active mixing of the solution to enhance the biosensing performance (Table S1). – Conventional mechanical stirring (e.g., stir bar) cannot meet the requirements of the current microsensing system due to its rather large size and complex mechanical components.…”