Tiny robots catch bacteria, microplastics in water

Free-swimming bacteria are some of the peskiest water pollutants around. They can travel and spread very quickly. They also form films, adhering to the inner walls of tanks and pipes; in this state, they become far more antibiotic resistant. Researchers at Martin Pumera's Future Energy and Innovation Lab at the Central European Institute of Technology have come up with a novel way to deal with these microbes. They designed magnetically controlled swarms of microbots equipped with "hands" to capture free-swimming bacteria and microplastics ( ACS Nano . 2024, DOI: 10.1021/acsnano.4c02115 ). The microbots, each less than 3 µm in diameter, are fabricated from Dynabeads (spherical beads that exhibit magnetic properties only when placed in a magnetic field) coated with strands of a polymer with antibacterial properties. The positively charged polymer forms the hands of the microbots and is designed to electrostatically trap bacteria and microplastics, whose surfaces are negatively charged.