NIR-II-triggered plasmonic catalysis with tip-localized enhancement: a strategy for hypoxic biofilm eradication on orthopedic implants

External light stimulation offers a promising approach to augment the catalytic performance of plasmonic nanozymes, holding great potential for applications in bacterial biofilm eradication. However, the rapid recombination of electron-hole pairs severely limits the utilization efficiency of light-induced hot carriers, thereby diminishing catalytic activity of the nanozymes. Furthermore, existing light-responsive plasmonic nanozymes are predominantly restricted to UV-Vis spectral ranges, which inherently constrains their therapeutic efficacy in deep-tissue environments due to poor penetration.

 

To overcome these challenges, in a new paper published in Light: Science & Applications, a team of scientists, led by Professor Jin-Wen Liu from Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences Guangxi Medical University, China, and co-workers engineered a near-infrared II (NIR-II) light-responsive plasmonic nanozyme by integrating gold nanobipyramids (Au NBPs) with tip-deposited platinum nanoparticles (Pt NPs).

 

This architecture, termed ePt-Au NBPs, achieves dual functional enhancements: (1) the Pt NPs modification induces a pronounced redshift of the localized surface plasmon resonance (LSPR) peak into the NIR-II window, enabling deep-tissue penetration; and (2) the optimized charge transfer dynamics significantly boost hot electron generation, yielding exceptional catalytic activity of plasmonic nanozymes under NIR-II irradiation.

 

Mechanistic studies demonstrated that the NIR-II-triggered LSPR drives simultaneous production of hydroxyl radicals (•OH) and localized hyperthermia. The •OH efficiently degrade extracellular DNA (eDNA), a structural pillar within the extracellular polymeric substance (EPS) matrix, thereby destabilizing biofilm integrity. Concurrently, the generated hyperthermia penetrates the compromised biofilm to achieve potent bacterial eradication even under hypoxic conditions.

 

In addition, surface functionalization with RGDC peptides endows the nanozyme with superior biocompatibility and osteogenic activity, ensuring seamless integration with bone implants.

 

The elaborately engineered ePt-Au NBPs/RGDC plasmonic nanozyme establish a foundational framework for developing next-generation smart coatings to combat implant-associated biofilm infections while fostering bone regeneration.

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