Wound healing properties and antibiofilm activity of hydrogel matrix containing nitric oxide, silver nanoparticles, and ciprofloxacin against Pseudomonas aeruginosa burn wound infection

Abstract

The high antibiotic resistance of Pseudomonas aeruginosa has led to significant issues and delays in wound healing, resulting in disruptions to the healing process. The present study evaluated the antibacterial effects and wound healing properties of a hydrogel matrix containing nitric oxide, silver nanoparticles, and ciprofloxacin (Hy-NO-Ag-Cip) against multi-drug-resistant (MDR) P. aeruginosa. The MDR P. aeruginosa was isolated from patients with burn wound infection. Hy-NO-Ag-Cip was synthesized, and its physicochemical characteristics were evaluated. The in vitro antibacterial and anti-biofilm effects of Hy-NO-Ag-Cip were analyzed. Burn wound infections were induced in 25 rats, and topical application was conducted to assess the antibacterial efficacy and wound healing characteristics of Hy-NO-Ag-Cip. The results showed that the fabricated hydrogels have a porous structure, with interconnected pores. The spectra of the formulated hydrogel loaded with AgNPs and the drug showed bands with similar frequencies and shapes to those of the final hydrogel. The Hy-NO-Ag-Cip minimum inhibitory concentration (MIC) was 250 µg/mL, and the 2× MIC of this hydrogel reduced mature biofilm by 65%. There was no toxic effect observed at the MIC concentration of Hy-NO-Ag-Cip on the L929 cell line. In the wound healing process, the group treated with Hy-NO-Ag-Cip exhibited a greater epithelial thickness, indicating enhanced wound healing compared to the other group. Hy-NO-Ag-Cip enhances antibiotic accumulation at the infection site through a controlled drug release, resulting in a substantial antibacterial action and improved wound healing.

Keywords: Pseudomonas aeruginosa; Antimicrobial resistance; Biofilms; Hydrogel matrix; Nitric oxide; Silver nanoparticles.

Fig. 1

SEM micrograph of the fabricated pure hydrogel. a NPs-loaded hydrogel. b NPs and drug-loaded hydrogel.

Fig. 2

FT-IR of a CS/PVMMA, b CS/PVMMA@NP, and c CS/PVMMA-NP-Cip hydrogels.

Fig. 3

Thermal analysis curves (DTG and DTA) of the designed hydrogel.

Fig. 4

The swelling data of hydrogel formulation.

Fig. 5

Drug and NPs releasing profile.

Fig. 6

The percentage of mature biofilm reduction after treatment with 2×MIC of drug platforms (The ANOVA was used for statistical analysis. mean ± SD, n = 3, *p < 0.05, **P value < 0.01).

Fig. 7

In vitro cytotoxicity effect of synthesized Hy-NO-Ag-Cip on the murine L929 fibroblast cell line.

Fig. 8

Comparison of closure percentage in groups of untreated, Hy-NO, AgNPs, SSD, and Hy-NO-Ag-Cip during 11 days’ follow-up. * and ns represent a p < 0.05 and insignificant, respectively. The ANOVA was used for statistical analysis.

Fig. 9

The histological assessment of infected wounds in both treated and untreated groups on days 4, 7, and 11 (× 10 magnification). The white, yellow, and red arrows indicate collagen, inflammatory cells, and the epithelial layer, respectively.

Fig. 10

The wound burden of bacteria on days 4 and 7 in rats was assessed by quantifying CFU growth. The treatment markedly reduced the bacterial count in the treated group relative to the other groups. (The ANOVA was used for statistical analysis. mean ± SD, n = 3, *p < 0.05, ns insignificant and **P value < 0.01).