Sci Rep. 2022 Oct 21;12(1):17646. doi: 10.1038/s41598-022-21725-z.
Chemically coated micro/nanoparticles are often used in medicine to enhance drug delivery and increase drug up-take into specific areas of the body. Using a recently discovered spontaneous symmetry breaking propulsion mechanism, we demonstrate that chemically coated microparticles can swim through mucus solution under precise navigation and that certain functionalizations can dynamically change propulsion behavior. For this investigation biotin, Bitotin-PEG3-amine, and biotin chitosan were chemically functionalized onto the surfaces of magnetic microparticles using an avidin-biotin complex. These chemicals were chosen because they are used prolifically in drug delivery applications, with PEG and chitosan having well known mucoadhesive effects. Coated microparticles were then suspended in mucus synthesized from porcine stomach mucins and propelled using rotating magnetic fields. The relationship between different chemical coatings, microparticle velocity, and controllability were thoroughly explored and discussed. Results indicate that the biotinylated surface coatings altered the propulsion behavior of microparticles, with performance differences interlinked to both magnetic field properties and localized mucus properties. Precisely controlled drug carrying microparticles are envisioned to help supplant traditional drug delivery methods and enhance existing medical techniques utilizing micro/nanoparticles.