Electroosmotic blood flow containing gold and silver nanoparticles through a microchannel: Effect of driving microorganisms

This study examines the impact of bioconvective transport of microorganisms in blood with suspended nanoparticles through a microchannel, relevant to biomedical and microfluidic applications. The Jeffrey non-Newtonian fluid model is utilized to characterize the blood and gold–silver ($\mathrm{Au\; -\; Ag}$) nanoparticles are suspended in it. The aim is to assess how electroosmotic forces, nanoparticles, and fluid rheology affect velocity, temperature, concentration, and microorganism distributions. The model assumes a laminar, incompressible flow of a Jeffrey fluid, influenced by pressure gradient, electroosmosis, and a transverse magnetic field. The electric potential is computed using the Poisson–Boltzmann equation with the Debye–Hückel linearization, valid for low surface potentials. Analytical solutions are obtained for velocity, temperature, concentration fields, and important characteristics such as Nusselt & Sherwood numbers. Due to the nonlinear nature of microorganism distribution, the Matlab bvp4c solver is employed to find the numerical solutions. Results show that higher volume fractions of $\mathrm{Au\; -\; Ag}$ nanoparticles enhance temperature, concentration, and microorganism distributions. The ratio of retardation to relaxation time parameter suppresses microorganism distribution. For purely electroosmotic-driven flow, microorganism distribution is profound compared to the presence of pressure. Also, the thermo-diffusion effect shows a clear correlation with the electroosmotic effect. We have observed that increasing the Soret number helps with concentration distribution and makes mass transfer more efficient, and its influence on microorganism transport varies with the electric double layer (EDL) thickness. We have also discovered that boosting the Hartmann number results in more microorganism buildup, all because it alters the flow structure. Even more importantly, a thinner electric double layer and a longer relaxation time greatly increase the volumetric flow rate while keeping the transfer efficiencies high. These outcomes have significant potential across various fields like chemical processing, the development of biochips for drug delivery, and biomedical engineering.