On-chip immunomagnetic bead swarm based on magnetic actuation and mechanical vibration for biological detection

Immunomagnetic bead (IMB)-based detection has great potential for biomedical applications. Passive and active strategies, including microfluidics and magnetic actuation methods, have been developed to mix IMBs and analytes efficiently. However, cost-effective on-site detection using a simple microfluidic chip is challenging, and miniaturization of the magnetic driving device is imperative for portability. In this study, we propose a novel mixing method for an on-chip IMB swarm via magnetic actuation and mechanical vibration. A microfluidic chip system coupled with double spiral magnetic coils and a vibration motor was fabricated. The aggregation behavior of IMBs under magnetic fields and the diffusion behavior of the IMB swarm under mechanical vibration were analyzed in detail. Based on the synergetic effects of magnetic actuation and mechanical vibration, we achieved the highly efficient capturing of Vibrio parahaemolyticus DNA and goat anti-human immunoglobulin G by mixing the IMB swarm with the microfluidic chip. In this case, the antigen detection rate could reach similar to 94.4%. Given its fascinating features, such IMB-microfluidic detection demonstrates significant potential for biomedical applications.