Boundary Layer Analysis of Second-Order Magnetic Nanofluid Flow with Carbon Nanotubes and Gyrotactic Microorganisms for Medical Diagnostics

This study investigates the boundary layer flow of a second-order magnetic nanofluid containing gyrotactic microorganisms and carbon nanotubes, aiming to enhance biosensor performance for medical diagnostics. Current biosensor technologies face limitations in sensitivity, accuracy, and reliability, which this research seeks to address by integrating carbon nanotubes into magnetic nanofluids to improve the electrical, mechanical, and thermal properties of diagnostic devices. A boundary layer analysis is performed using numerical simulations to examine the effects of key parameters, i.e., magnetic field, heat source, porous medium, and viscous dissipation on fluid behavior. The study employs boundary layer approximations and non-similarity transformations to convert the governing partial differential equations into dimensionless, nonlinear ordinary differential equations (ODEs), which are solved using MATLAB’s bvp4c technique. The results demonstrate that an increased magnetic number, heat source, and Eckert number enhance heat transfer, as indicated by a higher Nusselt number, while variations in fluid parameters show complex thermal interactions. The skin friction coefficient increases with higher fluid parameters, porosity, and magnetic field strength, indicating stronger fluid–solid interactions. Additionally, the study finds that higher porosity and magnetic field strengths reduce velocity profiles, while increasing magnetic field, Eckert number, porosity, and heat source raises the temperature profile. The Schmidt and Soret numbers significantly influence concentration distribution, with opposite effects. This research contributes to the advancement of medical biosensors by providing a deeper understanding of the fluid dynamics involved in nanofluid-based systems.