Self-Propelled MOF Micromotors: A Smart Solution for Antibiotic Pollution and Resistance Control

Abstract

The metalation of MOF (Metal Organic Frameworks) is one of the most popular tools in the post-synthetic modification (PSM) to expand its application horizon. The anisotropic metalation of MOF can produce Janus Particles (JPs) to act as selfpropelled micromotors (MM) and open a dimension in applications such as drug delivery, sensing, environmental remediation, and catalysis, etc. Antibiotic waste, discarded from an industry or excreted by humans or animals due to the overuse of antibiotics to treat various biological issues, has been causing resistance in bacteria, that were previously affected/ killed by these antibiotics, referred to as AMR (antimicrobial resistance). By an anisotropic metalation (Type I) of bidentate Zr-UiO MOF, consisting of a biphenyl dicarboxylic acid (H 2 bpdc) and 2,2'-bipyridine-5,5'dicarboxylic acid (H 2 bpydc) linkers, we have solvothermally synthesized selfpropelled Fe-Zr MOF MM (micro motor). Herein, the pyridine-based carboxylic linker will enable the addition of Fe anisotropically without perturbing the UiO framework to form self-propelled Fe-Zr MOF MM that could achieve an optimum linear speed of 197 μm/s in the presence of H 2 O 2 as a fuel and motion-stimulating agent (MSA). FTIR, XPS, XRD, EDAX (elemental data analysis), FESEM and TGA data confirm the formation of Fe-Zr MOF MM, keeping the original crystal structure of bidentate Zr-UiO MOF intact. The developed Fe-Zr MOF MM can degrade 60 % of amoxicillin, a penicillin group of antibiotics, within 25 mins in water under ambient conditions without any external stirring. The compositional analysis of degraded products by HPLC and HRMS also proved that β lactam group was completely destroyed and small molecular weight molecules were present in the degraded products. XPS analysis of Fe-Zr MOF MM and morphological images by FESEM inferred that the structural integrity of the MM remained unaltered after chemotactic catalytic activity. Thus, Fe-Zr MOF-MM is a self-propelling material that operates on a "degrade as it moves" principle toward amoxicillin, a penicillin-class antibiotic. It functions as an energy-efficient catalyst for the chemotactic degradation of penicillin-group antibiotics and holds promise as a potent, energy-saving tool in the fight against the growing threat of antimicrobial resistance (AMR).