(397e) Modeling and Optimization of Eddy Current-Induced Microfluidic Heating for Lab-on-a-Disc Platforms

Lab-on-a-disc systems represent a pivotal advancement in point-of-care diagnostics, offering a compact, efficient platform for integrating various laboratory functions onto a single microfluidic disc. They enable precise control of fluid manipulation through centrifugal forces, facilitating automated sample processing and analysis within a miniaturized rotating platform. This study introduces a novel approach for enhancing the functionality of lab-on-a-disc systems through the implementation of eddy current-induced microfluidic heating, aiming to unify the sample preparation and nucleic acid amplification processes. We developed a computational model that integrates the rotational dynamics of the spinning disc, embedded with metallic components, with the induction of eddy currents. The rotation of the disc alters the magnetic field within the conductors, invoking Lenz's Law to generate eddy currents in response to this dynamic magnetic environment. The simulation evaluates the impact of factors including the disc's angular velocity, the strength and orientation of the magnetic field, and the disc's geometry on the generation and distribution of eddy currents. Preliminary results show a direct correlation between the disc's angular speed and the intensity of the generated eddy currents, which in turn influences the temperature profiles within the disc. Variations in magnetic field strength, orientation, and disc geometry were systematically analyzed to optimize the heating mechanism for specific diagnostic applications. This includes the ability to achieve rapid thermal ramping rates and stable maintenance of target temperatures, essential for efficient DNA amplification. Experimentally, we validate our model's predictions by constructing a prototype lab-on-a-disc platform. The platform consists of a Poly(methyl methacrylate) (PMMA) disc embedded with copper pieces, rotated by a brushless DC motor in the presence of stationary neodymium magnets. The setup aims to replicate the modeled conditions, allowing for the observation of temperature variations across the disc due to eddy current-induced heating. This approach provides a direct comparison between the simulated predictions and experimental outcomes, demonstrating the model's accuracy in predicting the eddy currents' thermal effects on the disc. These results underscore the feasibility of using eddy current-induced heating in molecular diagnostics, offering a pathway towards the development of compact, efficient, and cost-effective devices capable of integrated sample preparation and stimulating thermally actuated reactions, thereby advancing point-of-care diagnostics.