# Gallium Liquid Metal Nanoparticles as Agents to Treat Multidrug‐Resistant Bacterial Infections

## TL;DR

Gallium liquid metal nanoparticles show promise in fighting drug-resistant bacteria, including MRSA and Pseudomonas aeruginosa, and may be used alone or with other antibiotics.

## Contribution

GaLM NPs demonstrate bactericidal and anti-biofilm activity against MDR bacteria and are safe to human cells at effective concentrations.

## Key findings

- GaLM NPs are bactericidal against MRSA with MIC and MBC values between 39 and 156 μg/mL.
- GaLM NPs show additive effects with colistin against Pseudomonas aeruginosa.
- GaLM NPs are safe to human keratinocyte cells at 1024 µg/mL.

## Abstract

Multidrug‐resistant (MDR) bacterial infections constitute one of the top global public health threats. This study investigated the potential of gallium liquid metal nanoparticles (GaLM NPs) as a new agent against MDR pathogens. GaLM NPs was bactericidal against methicillin‐resistant Staphylococcus aureus (MRSA) isolates and a vancomycin‐intermediate S. aureus reference strain (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values between 39 and 156 μg/mL). The bactericidal activity of GaLM NPs was supported by transmission electron microscopy showing marked ultrastructural changes in the cell envelope of MRSA USA300. GaLM NPs were bacteriostatic against selected Gram‐negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae) reference strains and isolates (MICs between 39 and 625 μg/mL). Furthermore, GaLM NPs demonstrated additive and bacteriostatic activity when combined with sub‐inhibitory concentrations of colistin against P. aeruginosa isolates. Additionally, GaLM NPs showed anti‐biofilm activity against MRSA USA300 (minimum biofilm eradication concentration of 625 μg/mL); morphology changes of GaLM NPs‐treated cells was demonstrated by scanning electron microscopy. Finally, GaLM NPs was safe to human epidermal keratinocyte cell line at 1024 µg/mL (6.5 × MIC). We conclude that GaLM NPs warrant further exploration for the effective treatment of Gram‐positive or Gram‐negative infections both alone and in combination with antimicrobial drugs.

Gallium liquid metal nanoparticles (GaLM NPs) are promising agents for treating multidrug‐resistant Gram‐positive and Gram‐negative bacterial infections.(A), Preparation of GaLM NPs suspension; (B, C), Morphology of GaLM NPs without and with F127, scale bar: 500 nm; (D), Diameter distribution of GaLM NPs; (E), TEM showing effects of GaLM NPs treatment on morphology of MRSA USA300; (F), SEM showing eradication of MRSA USA 300 biofilms by GaLM NPs.