Detection of Biofilm Extracellular Polymeric Substances After Treatment with Surfactant-Based Wound Gels

In wounds, biofilms form a diverse mix of cellular aggregates and self-producing extracellular polymeric substances (EPS). The development of EPS is important for biofilm establishment, tolerance to antimicrobials, and prolonged attachment. Biofilm establishment has been shown to lead to delayed wound healing and chronic inflammation. The major components of the EPS, eDNA, polysaccharides, and proteins, are vital to the formation and stability of biofilms and represent an issue in wound care as they are highly immunogenic. Therefore, interventions that aim to remove the macromolecules of the EPS are of interest for the break-up of biofilms in wounds. The aim of this study was to quantify the reduction of EPS components after treatment with a concentrated surfactant gel (CSG) with and without 1% silver sulfadiazine (CSG-SSD) using confocal laser scanning microscopy (CLSM).

Pseudomonas aeruginosa ATCC 700888 biofilms were grown in nutrient broth for 24 hours in a 12-well plate. The biofilms were then treated with the CSG and CSG-SSD for a further 24 hours. After treatment, biofilms were washed and stained with fluorescent dyes SYTOTM 9 and SYPRO Ruby for the quantification of eDNA and proteins, respectively. The biofilms were visualized by CLSM and treated biofilms were compared to an untreated control.

It was observed that biofilms treated with the CSGs had a marked decrease in fluorescence for EPS components in contrast to the untreated control.

The efficacy of two CSGs were assessed for their ability to lower components of the EPS and demonstrated a reduction in EPS components from P. aeruginosa biofilms. Treatments that break up the EPS and, as a consequence, the biofilm, can be beneficial to wound healing, supporting the use of the CSGs in wound care treatment and supporting the role of surfactants in biofilm management.