Jianjie Li,Xiaoli He,Huaide Jiang,Yi Xing,Bi Fu,Chengzhi Hu
Advances in the versatile design and synthesis of nanomaterials have imparted diverse functionalities to Janus micromotors as autonomous vehicles. However, a significant challenge remains in maneuvering Janus micromotors by following desired trajectories for on-demand motility and intelligent control due to the inherent rotational Brownian motion. Here, we present the enhanced and robust directional propulsion of light-activated Fe3O4@TiO2/Pt Janus micromotors by magnetic spinning and the Magnus effect. Once exposed to a low-intensity rotating magnetic field, the micromotors become physically actuated, and their rotational Brownian diffusion is quenched by the magnetic rotation. Photocatalytic propulsion can be triggered by unidirectional irradiation based on a self-electrophoretic mechanism. Thus, a transverse Magnus force can be generated due to the rotational motion and ballistic motion (photocatalytic propulsion) of the micromotors. Both the self-electrophoretic propulsion and the Magnus force are periodically changed due to the magnetic rotation, which results in an overall directed motion moving toward a trajectory with a deflection angle from the direction of incident light with enhanced speed, maneuverability, and steering robustness. Our study illustrates the admirable directional motion capabilities of light-driven Janus micromotors based on magnetic spinning and the Magnus effect, which unfolds a new paradigm for addressing the limitations of directionality control in the current asymmetric micromotors.
Droplet-based microreactors hold great promise for enzymatic reactions, but their efficiency is often hindered by static operation and poor mass transfer. This study tackles these limitations through the innovative application of dynamic rotating magnetic liquid marbles (LMs) stabilized by proteinaceous colloidosomes. The colloidosomes feature an outer layer of densely-packed hydrophobic silica nanoparticles and an inner zein layer that integrates magnetic particles and enzymes, enhancing hydrophobicity, magnetic responsiveness, and enzyme immobilization. As proof of the concept, glucose oxidase (GOx) is encapsulated within the colloidosomes and horseradish peroxidase (HRP) inside the LMs, respectively. The results demonstrate that the rotating LMs significantly accelerated enzymatic cascade reactions when exposed to an external magnetic field. Moreover, by applying this approach to biphasic enzymatic systems, positioning the LMs at the water/toluene interface yields a 2.2-fold increase in conversion rate compared to static systems, as shown in lipase-driven esterification reactions. This advancement not only broadens the potential applications of LMs but also offers a promising strategy for enhancing catalytic processes in heterogeneous systems.
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