Phage structure-mimicking broad spectrum antibacterial nanoparticles

Overview

Phage Structure-Mimicking Antibacterial Nanoparticles (PhANPs) are synthetic, non-immunogenic nano-materials designed to replicate the antibacterial mechanism of bacteriophages without using biological agents. These core-shell nanoparticles feature a tunable silica core studded with silver-alloyed gold nanospheres and coated with antimicrobial polymers, mimicking the spike spacing found on phage surfaces. The result is a broad-spectrum, antibiotic-free antimicrobial platform effective against multiple drug-resistant bacterial strains, including MRSA, P. aeruginosa, C. striatum, E. faecalis, A. baumannii, K. pneumoniae, and S. pyogenes. PhANPs have demonstrated >99.999% bacterial kill rates in solution and 100% surface contact kill on implant-grade steel, while maintaining biocompatibility with human skin cells and promoting wound healing without inflammation in animal studies.

Technical specifications

Key features:

• Size-tunable silica core (~25 nm) decorated with 3–5 nm silver-alloyed gold nanospheres
• Coating of rationally designed antimicrobial peptides or antimicrobial polymers
• Steric spacing of metallic nanospheres engineered to mimic bacteriophage spike geometry
• Effective against seven antibiotic-resistant bacterial strains at neutral pH
• Biocompatible with HaCaT keratinocytes (human skin cell model)
• In vivo biocompatibility demonstrated in mice wound healing studies
• Generally Recognized as Safe (GRAS) dispersible in ethanol and water
• Suitable for both liquid suspension and surface immobilization applications

Validation methods used:

• Bacterial viability assessed via growth curves, CFU/mL counts, and LIVE/DEAD fluorescence assays
• Biocompatibility evaluated using ethidium homodimer permeabilization assays
• In vivo wound healing studies in mice

Future validation plans include:

• Dose-dependent growth curves and CFU assays for pathogens of interest
• Mechanistic studies using electron microscopy, circular dichroism, confocal microscopy, and Raman spectroscopy
• In vivo testing on human skin plasminogen-expressing mice for bio-persistence, biocompatibility, and inflammation
• Histopathology, immunohistochemistry, ELISA for inflammatory markers, and histology imaging

Technology readiness level

PhANPs are currently at Technology Readiness Level (TRL) 4+, meaning the technology has been validated in laboratory and relevant in vivo settings. Kill efficacy, biocompatibility, and wound healing performance have all been demonstrated. An estimated one to two years of additional development is needed to advance toward commercial use, including formulation optimization, scale-up manufacturing, and expanded preclinical testing.