# Synergistic photothermal antibacterial efficacy and high biocompatibility of silver-carbon core-shell nanoparticles

## TL;DR

Researchers developed silver-carbon core-shell nanoparticles that effectively kill bacteria with light while being safe for human cells.

## Contribution

The study introduces Ag@C nanoparticles with high photothermal antibacterial efficacy and excellent biocompatibility.

## Key findings

- Ag@C nanoparticles showed excellent photothermal conversion efficiency under 808 nm near-infrared irradiation.
- Ag@C nanoparticles eradicated Methicillin-resistant Staphylococcus aureus (MRSA) with no significant cytotoxicity.
- Hemolysis tests confirmed the high biocompatibility of Ag@C nanoparticles.

## Abstract

Safe and effective antimicrobial treatment strategies are urgently required for the prevention and control of infectious diseases. While silver-based nanoparticles (AgNPs) are currently acknowledged as the most potent metal-based antibacterial agents, their potential cytotoxicity poses a significant barrier to further clinical applications. Herein, we synthesized carbonaceous coated silver nanocore (Ag@C) core-shell nanoparticles and investigated their material properties, biocompatibility, and antibacterial efficacy. The produced Ag@C exhibited a uniform core-shell structure with an overall diameter of 256.40 nm, a shell thickness of 92.20 nm, and a silver core diameter of 67.45 nm. Under irradiation with 808 nm near-infrared (NIR) irradiation, Ag@C demonstrated excellent photothermal conversion efficiency. The results from apoptosis detection via flow cytometry, CCK-8 cytotoxicity assays, and live/dead cell staining using Calcein-AM/PI, collectively indicated that Ag@C displayed no significant cytotoxicity. Hemolysis tests further confirmed the good biocompatibility of Ag@C. Quantitative analysis through plate counting assays revealed that Methicillin-resistant Staphylococcus aureus (MRSA) co-cultured with Ag@C were significantly eradicated by NIR irradiation; this finding was corroborated by bacterial live/dead staining observed under confocal laser scanning microscope (CLSM). Our results indicate that Ag@C combined with photothermal therapy (PTT) exhibits substantial antibacterial effects in vitro while maintaining high biosafety standards, suggesting promising prospects for clinical application.

The online version contains supplementary material available at 10.1186/s11671-026-04432-w.