Synthesis of photothermal antimicrobial cotton gauze using AuNPs as photothermal transduction agents

Abstract

Cotton gauze has been used as a wound dressing since the 19th century, and still plays an important role in current clinical therapies. However, the antimicrobial ability of cotton gauze is limited. In this work, gold nanoparticles (AuNPs) were used as photothermal transduction agents to synthesize modified photothermal antimicrobial cotton gauze. The modified cotton gauze was synthesized by immersing and heating the clinical cotton gauze with AuNPs solution. XPS, ICP-OES, FTIR, XRD and SEM characterizations confirmed that AuNPs were successfully decorated on the surface of cotton gauzes. Besides, the mechanical properties, air and water vapour permeability performance of cotton gauze were not changed after modification. Photothermal antimicrobial experiments confirmed that AuNPs modified on the cotton gauze could convert light to heat, inducing rapid temperature increase of the cotton gauze. And the heat could kill microbial cells permeated in the modified cotton gauze, giving it the potential of being used for photothermal antimicrobial therapy.

Scheme 1. Illustration of the synthesis and photothermal ability of AuNPs modified cotton gauze.

Fig. 1. (A) TEM image of the synthesized AuNPs, (B) ultraviolet-visible spectra of AuNPs solution, (C) temperature increasing curves of distilled water and AuNPs solutions at 0.2, 0.4 and 0.8 mM with increasing irradiation time.

Fig. 2. Characterization of the original, Au-1 and Au-2 cotton gauzes: (A) photos, (B) XPS spectra, (C) FTIR spectra, (D) XRD patterns.

Fig. 3. SEM images of the original, Au-1 and Au-2 cotton gauzes.

Fig. 4. Thermal images of the original, Au-1 and Au-2 cotton gauzes with different irradiation time.

Fig. 5. Relative cell viability of the original, Au-1 and Au-2 cotton gauzes via human skin fibroblasts using cells without cotton gauze as the control.

Fig. 6. OD values of (A) Candida albicans and (B) Escherichia coli solution permeated in the original, Au-1and Au-2 cotton gauzes, irradiated under xenon lamp and further cultured in fresh culture medium for 24 h.