Microswarm bridging effect for dual-surface biofilm eradication in submillimeter infection pockets.

Abstract

Biofilm infections in submillimeter interstices at soft tissue-implant/hard tissue interfaces (infection pockets) pose substantial health risks. Traditional surgical and microrobotic strategies struggle to address biofilms in these multicurvature spaces. Here, we report the bridging effect of microswarm self-assembled from magnetic hydrogel particles to eradicate biofilms in infection pockets. The microswarm dynamically bridges dual surfaces within infection pockets, enabling continuous, stable contact and force delivery across concave, plane, and convex surfaces through optimized thickness and shear force. The synergy of enzymatic degradation and mechanical disruption enhances biofilm eradication efficiency by eightfold compared to mechanical disruption alone. A multifunctional hydrogel filler is further used to remove biofilm debris and inhibit microbial recolonization, eventually achieving >99% biofilm elimination in ex vivo and in vivo models. This strategy uses the bridging effect, shape reconfigurability, and enzymatic-mechanical synergy of microswarm, offering a minimally invasive, site-specific solution for deep-tissue infections and persistent biofilms, with reduced reliance on antibiotics.