Silver nanoparticles built on viral biotemplate kill more bacteria and slow resistance rise

Antibiotics are no longer able to treat infections as effectively as they once did because many pathogens have developed resistance to these drugs. This phenomenon, known as antimicrobial resistance (AMR), claims over a million lives worldwide each year.

Scientists have long been searching for treatments to overcome AMR, and a discovery by researchers at the University of California takes a significant step forward. The team has developed a new type of silver nanoparticle (AgNP) that is much more effective against harmful bacteria and significantly slows the rise of antibiotic resistance.

The AgNP was designed with M13 phage – a rod-shaped virus that infects E. coli bacteria – as the biological template for particle growth, resulting in a potency 30 times higher than that of commercially purchased silver nanoparticles.

Current AgNPs still face significant challenges, including toxicity, low potency, and the rapid emergence of bacterial resistance. Researchers in this study overcame these issues through biotemplating, a process in which they used the M13 bacteriophage as a biological template for the synthesis of a range of silver nanoparticles.

As a result, the new AgNPs developed bacterial resistance at a 10-fold slower rate than commercial AgNPs, while showing superior potency against Gram-negative bacteria, including E. coli, Pseudomonas aeruginosa, and Vibrio cholerae.

Image source: Bagchi et al. (2025), Langmuir.