Magnetic Microswarm Composed of Porous Nanocatalysts for Targeted Elimination of Biofilm Occlusion

Abstract

Biofilm is difficult to thoroughly cure with conventional antibiotics due to the high mechanical stability and antimicrobial barrier resulting from extracellular polymeric substances. Encouraged by the great potential of magnetic micro-/nanorobots in various fields and their enhanced action in swarm form, we designed a magnetic microswarm consisting of porous Fe3O4 mesoparticles (p-Fe3O4 MPs) and explored its application in biofilm disruption. Here, the p-Fe3O4 MPs microswarm (p-Fe3O4 swarm) was generated and actuated by a simple rotating magnetic field, which exhibited the capability of remote actuation, high cargo capacity, and strong localized convections. Notably, the p-Fe3O4 swarm could eliminate biofilms with high efficiency due to synergistic effects of chemical and physical processes: (i) generating bactericidal free radicals (•OH) for killing bacteria cells and degrading the biofilm by p-Fe3O4 MPs; (ii) physically disrupting the biofilm and promoting •OH penetration deep into biofilms by the swarm motion. As a demonstration of targeted treatment, the p-Fe3O4 swarm could be actuated to clear the biofilm along the geometrical route on a 2D surface and sweep away biofilm clogs in a 3D U-shaped tube. This designed microswarm platform holds great potential in treating biofilm occlusions particularly inside the tiny and tortuous cavities of medical and industrial settings.

Tethered and Untethered 3D Microactuators Fabricated by Two-Photon Polymerization: A Review

“…For turning these microactuators into realistic applications, more effective, wireless, and milder stimuli should be further developed [158]. Considering that one important application of outfield driven microactuators is drug delivery in medical field [159], we think that magnetic and ultrasound driving will be the focus of research [160][161][162]. Moreover, electric driving and the multi-field coupling method are promising future directions.…”

Review on Recent Progress in Magnetic Nanoparticles: Synthesis, Characterization, and Diverse Applications

“…Recently, scientists have introduced the magnetic-fieldcontrolled swarming of micro/nanorobots, which has proved the ability of high loading capacity and strong convections in swarmlike motion (Yu et al, 2019;Wang et al, 2021). In this pursuit, Fe 3 O 4 mesoparticles (Fe 3 O 4 MPs) due to stable para-magnetism are widely employed for designing of magnetic microrobots (Dong et al, 2021). Copyright 2021, American Chemical Society (B) mechanistic Representation of artificial channel created by magnetic nanoparticles in infectious biofilms to improve antimicrobial penetration and enhance bacterial killing over the depth of a biofilm (Quan et al, 2019b).…”

“…Copyright 2019, Elsevier publishing group. (Dong et al, 2021). In addition, they exhibit intrinsic peroxidaselike properties, which means that the Fe element in Fe 3 O 4 MPs can proceed the Fenton reaction, generating hydroxyl free radicals (•OH) that can destroy the biofilm matrix and kill bacteria cells (Figure 3A).…”

“…Recently, scientists have introduced the magnetic-field-controlled swarming of micro/nanorobots, which has proved the ability of high loading capacity and strong convections in swarm-like motion ( Yu et al, 2019 ; Wang et al, 2021 ). In this pursuit, Fe 3 O 4 mesoparticles (Fe 3 O 4 MPs) due to stable para-magnetism are widely employed for designing of magnetic microrobots ( Dong et al, 2021 ). In addition, they exhibit intrinsic peroxidase-like properties, which means that the Fe element in Fe 3 O 4 MPs can proceed the Fenton reaction, generating hydroxyl free radicals (•OH) that can destroy the biofilm matrix and kill bacteria cells ( Figure 3A ).…”

Nanomaterial Shape Influence on Cell Behavior

“…However, most papers describe the application of isotropic nanosized particles [ 163 ], as well as the mutual interaction of magnetic nanoparticle results in terms of vortex formation, which is efficiently operated by a magnetic field, and have been focused on accurate therapy [ 164 , 165 , 166 ] and cargo delivery [ 167 , 168 ]. Dong et al designed a magnetic vortex (microswarm) consisting of porous magnetite particles, which, under the action of the rotating magnetic field, could disrupt the biofilm and generate ROS [ 169 ]. Moreover, the presented microswarm can be transported to confinement and narrow spaces for the effective disruption of biofilms.…”