On-demand pulling-off of magnetic nanoparticles from biomaterial surfaces through implant-associated infectious biofilms for enhanced antibiotic efficacy

Biomaterial-associated infections can occur any time after surgical implantation of biomaterial implants and limit their success rates. On-demand, antimicrobial release coatings have been designed, but in vivo release triggers uniquely relating with infection do not exist, while inadvertent leakage of antimicrobials can cause exhaustion of a coating prior to need. Here, we attach magnetic-nanoparticles to a biomaterial surface, that can be pulled-off in a magnetic field through an adhering, infectious biofilm. Magnetic-nanoparticles remained stably attached to a surface upon exposure to PBS for at least 50 days, did not promote bacterial adhesion or negatively affect interaction with adhering tissue cells. Nanoparticles could be magnetically pulled-off from a surface through an adhering biofilm, creating artificial water channels in the biofilm. At a magnetic-nanoparticle coating concentration of 0.64 mg cm-2, these by-pass channels increased the penetrability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms towards different antibiotics, yielding 10-fold more antibiotic killing of biofilm inhabitants than in absence of artificial channels. This innovative use of magnetic-nanoparticles for the eradication of biomaterial-associated infections requires no precise targeting of magnetic-nanoparticles and allows more effective use of existing antibiotics by breaking the penetration barrier of an infectious biofilm adhering to a biomaterial implant surface on-demand.

Automated summary

This study introduces a novel method using magnetic nanoparticles to eradicate biomaterial-associated infections by creating artificial water channels in biofilms, allowing increased penetrability of antibiotics and enhanced killing of biofilm inhabitants. This innovative approach does not require precise targeting of magnetic nanoparticles and breaks the penetration barrier of infectious biofilms adhering to biomaterial implants on-demand.