Recent Developments in Metallic Degradable Micromotors for Biomedical and Environmental Remediation Applications

Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.

Enhanced catalytic degradation of organic pollutants by multi-stimuli activated multiferroic nanoarchitectures

Smart catalysts that can simultaneously utilize multiple energy sources will have a significant positive impact on the inefficiencies of conventional environmental remediation approaches,and will address their high energy demands.In this work,we have manufactured multiferroic magnetoelectric photocatalysts that can be simultaneously activated using multiple energy sources for the degradation of organic pollutants.The catalysts are composed of CoFe2O4@BiFeO3(CFO@BFO)nanooctahedrons(NOs),CFO@BFO nanocubes(NCs),and CFO@BFO nanowires(NWs),and were successful in harnessing energy from three different energy sources,including UV-vis light,acoustically mediated mechanical vibrations and magnetic fields.The CFO@BFO NOs displayed the most enhanced degradation,reaching 93%,96%,and 99%degradation of RhB dye within 1 h under light,ultrasound,and magnetic fields,respectively.When these energy sources were used simultaneously,significantly increased reaction rates were observed compared to the single-energy source stimulation.Results of radical trapping experiments indicate that radical species i.e.,OH·and O2·^-play a dominant role in catalytic degradation of organic pollutant,RhB,under all three stimuli.These results will contribute significantly to the development of new environmental technologies that are highly versatile in nature and able to adapt to changing environments to deliver efficient environmental remediation.