# Zinc-Based Nanoparticles Reduce the Bacterial Burden and Protect Collagen in a Mouse Cutaneous Wound Model

## TL;DR

Zinc nanoparticles reduce bacteria in skin wounds and protect collagen in mice, offering a new approach for wound treatment.

## Contribution

Zinc sulfide nanoparticles disrupt biofilms and protect collagen in mouse wounds, showing dual therapeutic potential.

## Key findings

- Zinc sulfide nanoparticles effectively disrupt bacterial biofilms and reduce bacterial burden in mouse skin wounds.
- ZnS nanoparticles inhibit collagen degradation and maintain collagen levels in wound tissue.
- ZnS nanoparticles downregulate genes involved in Pseudomonas aeruginosa biofilm formation.

## Abstract

The persistent threat of multidrug-resistant bacteria,
particularly
within biofilms, continues to undermine conventional antimicrobial
therapies. In this study, we explored the potential of zinc oxide
(ZnO) and zinc sulfide (ZnS) nanoparticles (NPs) as alternative strategies
to target clinically relevant bacteria such as Staphylococcus
aureus, Klebsiella oxytoca, and Pseudomonas aeruginosa. Both
NPs exhibited effective antibacterial activity against planktonic
forms, with ZnO more potent in vitro. However, ZnS-NPs
were more efficacious in disrupting mature biofilms by compromising
their metabolic activity. Scanning electron and confocal microscopy
revealed that Zn-NP treatment compromised the structural integrity
of the biofilms. ZnS-NPs also triggered a marked downregulation of
genes associated with P. aeruginosa exopolysaccharide biosynthesis (e.g., pslA and algC), suggesting specific interference in biofilm formation
pathways. Topical treatment of skin wound infection in Balb/c mice
led to a significant reduction in bacterial burden. Notably, while
Zn-NPs did not promote initial wound healing, they inhibited the degradation
of collagen by bacteria and/or helped maintain collagen levels in
the skin of the mice. These findings demonstrate that Zn-NPs effectively
reduce early bacterial burden in mouse skin wounds while preserving
cutaneous tissue collagen integrity, establishing their dual therapeutic
potential as both antimicrobial and tissue-protective agents in wound
management.