Methamphetamine Removal from Aquatic Environments by Magnetic Microrobots with Cyclodextrin Chiral Recognition Elements

The growing consumption of drugs of abuse together with the inefficiency of the current wastewater treatment plants toward their presence has resulted in an emergent class of pollutants. Thus, the development of alternative approaches to remediate this environmental threat is urgently needed. Microrobots, combining autonomous motion with great tunability for the development of specific tasks, have turned into promising candidates to take on the challenge. Here, hybrid urchin-like hematite (alpha-Fe2O3) microparticles carrying magnetite (Fe3O4) nanoparticles and surface functionalization with organic beta-cyclodextrin (CD) molecules are prepared with the aim of on-the-fly encapsulation of illicit drugs into the linked CD cavities of moving microrobots. The resulting mag-CD microrobots are tested against methamphetamine (MA), proving their ability for the removal of this psychoactive substance. A dramatically enhanced capture of MA from water with active magnetically powered microrobots when compared with static passive CD-modified particles is demonstrated. This work shows the advantages of enhanced mass transfer provided by the externally controlled magnetic navigation in microrobots that together with the versatility of their design is an efficient strategy to clean polluted waters. The study explores the use of magnetic cyclodextrin (CD) functionalized microrobots for cleaning water contaminated with drug residues, specifically methamphetamine. These microrobots, with a hematite/magnetite core and CD surface, enhance pollutant removal due to their combined magnetic movement and hydrophobic cavities of CDs on microrobot surfaces. The design emphasizes autonomous movement, improved mass transfer, and targeted functionalization for effective remediation.image