Bubble jet propulsion of a “Flying Shuttle” zinc phosphate micro robot driven by enzyme-catalyzed reaction

[Display omitted] •CAT@Zn3(PO4)2 MR are prepared using a gentle and facile biomineralisation strategy.•Good biocompatibility of CAT@Zn3(PO4)2 MR.•CAT@Zn3(PO4)2 MR can be self-driven at low H2O2 concentrations.•CPT-11@CAT@Zn3(PO4)2 MR can remain remarkably stable under physiological conditions, but is rapidly released under acidic conditions. Synthetic micro/nano robots have great potential for applications in controlled release of drugs, biosensing, medical imaging, and other fields due to the advantages of tiny size, flexible movement and precise targeting. However, currently developed micro/nano robots are limited by their complex preparation processes, potential systemic toxicity and poor biodegradability. Herein, the work reports a facile and mild biomimetic strategy for fabricating a micro-robot that is driven at low fuel concentrations and with good biocompatibility and biodegradability. To demonstrate the feasibility of the strategy, we directly use catalase as organic component, zinc (II) as inorganic component to construct organic–inorganic hybrid micro robot. The catalase-zinc (II) micro robot (CAT@Zn3(PO4)2 MR) had a “flying shuttle” morphology with a particle size of ∼3 μm and enzyme loading of 27.7%, great stability and biocompatibility. Moreover, the flying shuttle can achieve self-propulsion by decomposing oxygen bubbles generated by 0.5% H2O2. This is especially significant for future applications of micro/nano robots in biological environments, especially in systems where rapid autonomous movements of fuels occur at physiological concentrations. In addition, these robots can encapsulate and transport drug by themselves in a simple way, performing drug release via a pH-responsive regulatory mechanism.