Characterization of silk sutures coated with propolis and biogenic silver nanoparticles (AgNPs); an eco-friendly solution with wound healing potential against surgical site infections (SSIs)

Abstract

Background/aim: Bacterial adherence to a suture material is one of the main causes of surgical site infections. An antibacterial suture material with enhanced wound healing function may protect the surgical site from infections. Thus, the present study aimed to investigate the synergistic effect of propolis and biogenic metallic nanoparticles when combined with silk sutures for biomedical use.

Materials and methods: Silver nanoparticle (AgNP) synthesis was carried out via a microbial-mediated biological route and impregnated on propolis-loaded silk sutures using an in situ process. Silk sutures fabricated with propolis and biosynthesized AgNPs (bioAgNP-propolis-coated sutures) were intensively characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The antibacterial characteristics of the bioAgNP-propolis-coated sutures were evaluated using the agar plate method. The biocompatibility of the bioAgNP-propolis- coated sutures was evaluated using 3T3 fibroblast cells, and their wound-healing potential was also investigated.

Results: BioAgNP-propolis-coated sutures displayed potent antibacterial activity against pathogenic gram-negative and gram-positive bacteria, Escherichia coli and Staphylococcus aureus, respectively. BioAgNP-propolis-coated silk sutures were found to be biocompatible with 3T3 fibroblast cell culture. In vitro wound healing scratch assay also demonstrated that the extract of bioAgNP-propolis-coated sutures stimulated the 3T3 fibroblasts’ cell proliferation.

Conclusion: Coating the silk sutures with propolis and biogenic AgNPs gave an effective antibacterial capacity to surgical sutures besides providing biocompatibility and wound healing activity.

Keywords: Propolis; silver nanoparticle; suture; antibacterial; wound healing; cytotoxicity.

Figure 1

SEM micrographs of control suture (left) and bioAgNP-propolis-coated suture (right). The bar represents 100 μm.

Figure 2

EDS spectrums of control suture and bioAgNP-propolis-coated suture.

Figure 3

Thermogravimetic analysis of bioAgNP-propolis-coated sutures (blue line)and noncoated sutures (control group, red line).

Figure 4

Differential scanning calorimetry curves of bioAgNP-propolis-coated sutures (blue line) and noncoated sutures (control group, red line).

Figure 5

Antibacterial activity of bioAgNP-propolis-coated sutures against S. aureus and E. coli.

Figure 6

Images of scratch wound healing assay: a) 0 h, b) basal cell culture medium after 24 h, and c) extract of bioAgNPpropolis- coated suture after 24 h. The bar represents 500μm.

Figure 7

Cell viability of 3T3 fibroblasts treated with propolisbioAgNP- coated suture extracts at 1, 4, 8, and 10 days (reported as a percentage of the negative controls).