可切换的趋化行为对于运动微生物趋利避害至关重要。在该论文中，我们首次演示了一种能够感知周围环境中燃料浓度变化而自主调节驱动机理和运动方向的酶驱动微米马达，它由脲酶修饰在双面神罐状微米颗粒内表面组成。该微米马达利用罐状结构的空间限制效应和脲酶与尿素之间的特异性催化反应，其驱动机理能够随周围环境中局部燃料浓度的变化，在离子型扩散泳和微气泡反冲驱动之间实现可逆转换。当有匀强磁场时，由于该微米马达的运动姿态被规范，还能进一步表现出可切换的正、负趋化行为。另外，在生理尿素浓度下，微气泡反冲驱动机理使得微米马达的运动速率显著提升，可达60 μm/s，约30体长/秒。这说明该酶驱动微米马达具有强劲的驱动力，将有望在生物医药领域实现实际应用。

       原文详细摘要如下：Switchable chemotaxis is vital for motile microorganisms to seek benefits or avoid harms. Inspired by nature, we herein, for the first time, demonstrate an artificial enzyme-powered micromotor which can autonomously regulate the propulsion mechanism as well as motion directionality by sensing solely the change of fuel concentration (Cf) in its surroundings. The as-designed micromotors have a pot-like microstructure with ureases immobilized on the inner surface. With the confined effect of the pot-like microstructure and unique features of urease catalytic reaction that molecular products are further reacted into ions, their propulsion mechanism can be reversibly adjusted between ionic diffusiophoresis and microbubble recoils when Cf changes. Consequently, the as-developed micromotors under magnetic field are able to self-turn back if local Cf differs greatly in their surroundings, indicating the achievement of achieve positive and negative chemotaxis by sensing local Cf. Meanwhile, the micromotors also show highly enhanced migration speed by microbubble-ejection, up to 60 μm/s, around 30 body lengths per second at physiological urea concentrations. The peculiar design strategy based on pot-like microstructures further enables the mesoporous silica outer surface to be easily functionalized for applications such as stimuli-responsive delivery-associated therapies besides for “smart” artificial micro/nanomotors (MNMs), and thus promote their in vivo biomedical applications.