The Effect of Gamma Rays on Gelatin/ Chitosan as bioactive wound-healing dressing physico-chemical and Biological Properties

Abstract In this research, Gelatine (GEL)/ Chitosan (CH) wound dressing was prepared and irradiated with gamma rays from ۶۰Co source for wound healing applications. GEL-CH composite characterization and functional properties were determined. The structural changes occurring after γ-irradiation at doses from ۵ to ۲۵ kGy were reported by physico-chemical techniques such as Electron Paramagnetic Resonance (EPR), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS) studies. The antioxidant capacity was studied using DPPH (۱,۱-diphenyl-۲-picrylhydrazyl free radical) scavenging and the antibacterial activities of Staphylococcus aureus and Escherichia coli were observed using liquid medium. Results revealed that EPR spectroscopy of un-irradiated GEL-CH showed ۲ paramagnetic centers correspond to g=۲.۰۷۷ and g= ۲.۰۷۹. After irradiation, no active centre was appeared. A dose-dependent decrease in the central signal intensity was detected, then the EPR signal intensity almost disappears at ۲۰ kGy. Gamma rays caused a slight increase in ion conductivity. FTIR suggest a slightly crosslinking phenomenon at ۲۰ kGy. The XRD analysis does not show peak indicating crystallinity between a range of ۲θ (۱۵–۳۰°). Moreover, γ-irradiation elevated the Scavenging DPPH radical activity (۰.۷۵ ± ۰.۰۷%). Gamma rays did not affect the antibacterial activity of GEL-CH wound dressing against pathogenic bacteria. The innovative results showed that the required γ-radiation for sterilization was ranged from ۵ to ۲۵ kGy. It permits to improve the physico-chemical and biological properties and maintain the native structural integrity of the GEL/ COL wound dressing

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Keywords: Gelatin ، Chitosan ، Wound Dressing ، γ-irradiation ، Electron Paramagnetic Resonance