Chitosan nanofiber biocomposites for potential wound healing applications: Antioxidant activity with synergic antibacterial effect

Abstract

Bacterial wound infection is one of the most common nosocomial infections. The unnecessary employment of antibiotics led to raising the growth of antibiotic-resistant bacteria. Accordingly, alternative armaments capable of accelerating wound healing along with bactericidal effects are urgently needed. Considering this, we fabricated chitosan (CS)/polyethylene oxide (PEO) nanofibers armed with antibacterial silver and zinc oxide nanoparticles. The nanocomposites exhibited a high antioxidant effect and antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Besides, based on the results of the cell viability assays, the optimum concentration of ZnONPs and AgNPs in the nanofibrous mats is 0.2% w/v and 0.08% w/v respectively and had no cytotoxicity on fibroblast cells. The scaffold also showed good blood compatibility according to the effects of coagulation time. As well as significant fibroblast migration and proliferation on the wound margin, according to wound-healing assay. All in all, the developed biocompatible, antioxidant, and antibacterial Ag-ZnO NPs incorporated CS/PEO nanofibrous mats showed their potential as an effective wound dressing.

Keywords: antibacterial; antioxidant; chitosan/polyethylene oxide nanofibers; electrospun; silver nanoparticles; wound healing; zinc oxide nanoparticles.

FIGURE 1

Morphological characterization of the prepared electrospun mats by FESEM and fiber diameter distribution of (a) Bare CS NFs; (b) CS NFs adorned with AgNPs; (c) CS NFs adorned with ZnONPs; (d) CS NFs adorned with AgNPs‐ZnONPs. The scale bar is 500 nm. AgNPs, silver nanoparticles; CS, chitosan; NF, nanofiber; SEM, scanning electron microscopy; ZnONPs, zinc oxide nanoparticles

FIGURE 2

(a) FTIR spectra of CS/PEO/AgNPs, CS/PEO/ZnONPs, and CS/PEO/AgNPs/ZnONPs. (b) Spotted analysis of the AgNPs‐CS, ZnONPs‐CS, AgNPs‐ZnONPs‐CS mats: The results confirm the presence of AgNPs and ZnONPs in mats. AgNPs, silver nanoparticle; CS: chitosan. (c) Map analysis of the AgNPs‐CS, ZnONPs‐CS, AgNPs‐ZnONPs‐CS mats: the presence and distribution of the elements in the mat were confirmed. The percentage of these elements was also determined. Ag, silver; AgNPs, silver nanoparticles; C, carbon; CS, chitosan; N, nitrogen; O, oxygen; Zn, zinc; ZnONPs, zinc oxide nanoparticles

FIGURE 3

Tensile diagram of a composite scaffold containing: (a) AgNPs, (b) ZnONPs, (c) AgNPs‐ZnONPs

FIGURE 4

(a) The antibacterial effect of the prepared nanofibrous mats against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Inhibition zone of the various contents of CS, AgNPs, ZnONPs, and AgNPs‐ZnONPs mats compared with selected antibiotic(Ampicillin, Gentamicin, and Penicillin), (b) schematic antibacterial mechanisms of silver and zinc oxide nanoparticles (****p < 0.0001; *p < 0.05)

FIGURE 5

DPPH methods evaluated the antioxidant properties of prepared scaffolds. (a) relative SC₅₀ of prepared nanofibrous mats. (b) AgNPs/CS/PEO, (c) ZnONPs/CS/PEO, (d) AgNPs/ZnONPs/CS/PEO

FIGURE 6

(a) Biocompatibility and viability of fibroblast cells using MTT. (b) Fibroblast cells proliferation and viability assay using CCK‐8 (*p = 0.02, **p = 0.002, ***p < 0.001). AgNPs represent chitosan/polyethylene oxide scaffolds containing silver nanoparticles containing of 0.08, 0.16, and 0.32% w/v. ZnONPs represent chitosan/polyethylene oxide scaffolds containing zinc oxide nanoparticles containing 0.2, 8.3, and of 27% w/v. Samples Mix1 and Mix2 represent chitosan/polyethylene oxide scaffolds containing both silver and zinc oxide nanoparticles containing 0.28% w/v (0.20% ZnO + 0.08% Ag) and 8.38% (0.83% ZnO + 0.08% Ag). (c) The hemolysis ratio of different sample

FIGURE 7

(a) Representative bright‐field images show HDF cell migration after the scratch at time 0 and after 24 h of sample incubation compared with controls. (b) The wound area is expressed as the remaining area uncovered by the cells. The scratch area at time point 0 h, and after 24 h for the samples. (c) Wound closure is expressed as the percentage of the closure of the scratched gap after 24 h. Results are the means of three measurements (*p < 0.05)

FIGURE 8

Scheme of (a) stages of wound healing. (b) Schematic illustration for the nanofibrous composite mats with antibacterial properties and trigger the cell migration for wound healing