ICG@ZIF@HA Nanoparticles and GO-Loaded Freeze-Drying Microneedles Mediated PDT/PTT Dual-Modal Phototherapeutic for Efficient Bacterial Biofilm Elimination

Biofilms, which are dense bacterial aggregates that form protective adhesion layers on surfaces, are associated with chronic wound infections, severe acne, and various other bacterial infection sites. However, the increasing antibiotic resistance of bacteria within biofilms and the limited penetration capacity of conventional treatments pose significant therapeutic challenges. To address these issues, we engineered a freeze-drying microneedle system integrating indocyanine green-loaded ZIF-8/hyaluronic acid nanoparticles (ICG@ZIF@HA NPs) and graphene oxide (GO) for dual-modal phototherapy. Notably, the microneedles demonstrated robust mechanical strength, enabling penetration through 140 μm-thick Staphylococcus aureus biofilms. Subsequently, the disruption of the biofilm's structural integrity facilitated the release of ICG@ZIF@HA NPs from the microneedle tips into deeper biofilm regions. Moreover, the nanoparticles exhibited pH-triggered release kinetics, with over 80% of ICG released at pH 5.5 within 2 h, and generated reactive oxygen species (ROS) under 808 nm near-infrared (NIR) irradiation. Meanwhile, the GO in the backing provided localized hyperthermia, reaching 55 °C within 500 s under NIR exposure. By combining ROS generation and bacterial membrane disruption, the microneedle system achieved a synergistic antimicrobial effect, effectively inhibiting bacterial growth and eliminating biofilms under NIR irradiation. Thus, this study establishes a robust foundation for integrating antimicrobial therapy with microneedle technology, offering a safer and more efficient strategy for biofilm eradication.