(266a) Eddy Current-Driven Thermal Control in Centrifugal Microfluidics for Integrated Diagnostics

Centrifugal microfluidic platforms, or lab-on-a-disc systems, have emerged as transformative tools for point-of-care (POC) diagnostics, consolidating complex laboratory processes into a single, compact rotating disc. These systems exploit centrifugal forces to automate fluid handling, but integrating thermal control for nucleic acid amplification and sample preparation remains a challenge. This work presents an innovative eddy current-based heating strategy to enhance lab-on-a-disc functionality, enabling seamless unification of sample processing and DNA amplification without external heating elements. We developed a computational framework to simulate the interplay between the disc’s rotational dynamics and eddy current generation within embedded metallic elements. As the disc spins in a stationary magnetic field, changes in magnetic flux—governed by Lenz’s Law—induce eddy currents, producing localized heat. The model explores how disc rotation speed, magnetic field intensity, field alignment, and disc design influence the magnitude and spatial distribution of these currents, ultimately shaping the thermal landscape across the microfluidic channels. Simulations reveal that higher angular velocities amplify eddy current intensity, driving rapid temperature increases, while strategic adjustments in magnetic field strength and disc geometry allow precise tuning of heating profiles—critical for achieving the elevated temperatures and stability required for DNA amplification. To test these predictions, we fabricated a prototype using a Poly(methyl methacrylate) (PMMA) disc with integrated copper segments, spun by a brushless DC motor amidst fixed neodymium magnets. Experimental measurements of temperature gradients across the disc closely matched the simulated outcomes, validating the model’s ability to predict thermal behavior induced by eddy currents. This eddy current-driven approach eliminates the need for conventional heaters, offering a streamlined, cost-effective solution for thermally regulated reactions on a microfluidic scale. By enabling integrated sample preparation and amplification, this technology advances the development of efficient, portable lab-on-a-disc systems, poised to elevate POC diagnostics in resource-limited settings.