The coronavirus has been rapidly disseminating across the globe over an extended period, leading to an immeasurable loss of lives. The pro‎mp‎t identification of this ailment contributes to expeditious treatment. In the current investigation, a three-dimensional finite element simulation has been conducted to scrutinize and comprehend the process of attachment between the antibody complexes (ligand) that are immobilized to the reaction surface and the antigen (analyte) pertaining to the spike protein of the coronavirus. To enhance and optimize the efficacy of the binding reaction and diminish the mass transfer resistance, the employment of alternating current electrothermal force (ACET) and the spiral geometry of the microfluidic biosensor have been implemented. The fusion of these two elements expedites the transportation of analytes towards the reaction surface and ultimately facilitates and enhances the binding reaction. The principal objective of this thesis is to truncate the duration required for detecting the presence of the coronavirus. The utilized structure encompasses a spiral microchannel wherein the active surface and electrodes are situated as curved surfaces. The simulation outcomes demonstrate that by applying Vrms voltage to the spiral microfluidic biosensor, the detection time can be augmented by 68% in comparison to the absence of voltage. In addition, this research encompasses parametric studies carried out on spiral geometry. In the investigation of the impact of varying the length of the electrode on the time it takes to detect the virus, augmenting the length of the electrode can enhance the virus detection time by 8%. Through an analysis of the temperature boundary conditions, five distinct scenarios were explored and ultimately, the most favorable scenario for minimizing the detection time was identified when the upper wall of the microchannel is at a temperature below 300 K and the lower wall is thermally insulated. This scenario resulted in a noteworthy 36% reduction in detection time, as compared to the detection time of the biosensor in its initial state (without the application of parametric temperature boundary conditions). By eva‎luating alterations in the rate constants of adsorption and desorption, two modes of utilization, both with and without the application of electrothermal force, were investigated. Specifically, when the electrothermal force is applied at the optimal voltage and the absorption and desorption rate constants are increased, the detection time is improved by an impressive 71%, as compared to the initial state (with no application of electrothermal force). In terms of a functional comparison between straight and spiral geometries for determining the virus detection time under applied voltage, the simulation results demonstrate that the spiral geometry possesses a slight advantage of approximately 2-7% at various voltages, in terms of its ability to detect the virus, as compared to the straight geometry.

محسن نصراصفهاني

مهدي ستاري نجف آبادي , حميد زيلوئي