Untethered Microrobot Motion Mechanism With Increased Longitudinal Force

The importance of an untethered microrobotic platform that can operate on high flowrate microfluidic channels for in vitro applications is increasing rapidly. This article presents a method to manipulate a microrobot in a fluidic chip when high flowrates (4 ml/min, 82.304 mm/s) are applied. This method is based on a novel permanent magnet-based diamagnetic levitation configuration. This configuration includes a thin layer of pyrolytic graphite, which is placed just below the microrobot. In this way, microrobot stability and manipulation capability are increased. Also, we aim to increase the longitudinal forces imposed on the microrobot to withstand the drag force proportional to the flowrate. Hence, magnetic field lines are generated more linearly around the microrobot by a different combination of permanent magnets. The proposed magnetic configuration, named KERKAN configuration, significantly improves the microrobot's longitudinal forces. In this configuration, two different ring-shaped ferromagnetic magnets are used. One of the magnets has a smaller diameter than the other magnet. A combination of one smaller and one bigger magnet is placed above and below the microrobot. To validate the advantages of this configuration, analytical and simulation studies are conducted. Their results are then compared with experimental results. Experimental results are on par with analytical and simulation studies. KERKAN configuration has a lower displacement than the next best configuration at the highest flowrate we applied (relatively 3301 mu m, %21.8).

Automated summary

This article introduces a method to operate a microrobot in high flowrate microfluidic channels using a novel permanent magnet-based configuration, improving the stability and manipulation capability of the microrobot, and increasing its longitudinal forces. Experimental results show that the proposed magnetic configuration, named KERKAN configuration, significantly outperforms other configurations.