Particle dispersion and mixing characteristics on the surface of a closed microchamber with magnetic artificial cilia

Inspired by the versatility of cilia, magnetic artificial cilia (MAC) are used to mimic cilia on the surface of biological organs. The application of MAC is currently focused on micro mixing, micro pumps, surface self-cleaning, etc. In order to imitate and study molecular dispersion during biological detection, MAC are utilized in this study to realize enhanced mixing and dispersion of magnetic particles suspended in a customized microchamber and the mixing efficiency is measured experimentally. With permanent magnets rotating outside the microchamber, the top of MAC is actuated to move periodically in a scallop-shape path, which can introduce internal circulation flow and particle migration in the chamber. Mixing conducted with MAC rows and arrays in different spacing are evaluated and compared. Four kinds of micro particle are chosen to display the performance of particles under the interference of MAC. It is found that arrays MAC with larger density would render higher mixing efficiency and less mixing time due to the larger flow velocity near the MAC. The alternating magnetic field generated by dual magnets combined with MAC can make the magnetic particles overcome the agglomeration and enhance mixing. Microfluidic chip with MAC in microchamber is demonstrated to be convenient and efficient for repeating separation-mixing processes of micro particles and it can be a promising micro device for mixing progress in various biological and chemical applications in the future.