Salma Bessalah, Samira Jbahi, Mouldi Zagrouba, Hajji Sawsen, Amel Raoufi, Mustpha Hidouri,
Volume 19, Issue 2 (6-2022)
Abstract
Abstract
In this research, Gelatine (GEL)/ Chitosan (CH) wound dressing was prepared and irradiated with gamma rays from 60Co source for wound healing applications. GEL-CH composite characterization and functional properties were determined. The structural changes occurring after γ-irradiation at doses from 5 to 25 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 (1,1-diphenyl-2-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 2 paramagnetic centers correspond to g=2.077 and g= 2.079. 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 20 kGy. Gamma rays caused a slight increase in ion conductivity. FTIR suggest a slightly crosslinking phenomenon at 20 kGy. The XRD analysis does not show peak indicating crystallinity between a range of 2θ (15–30°). Moreover, γ-irradiation elevated the Scavenging DPPH radical activity (0.75 ± 0.07%). 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 5 to 25 kGy. It permits to improve the physico-chemical and biological properties and maintain the native structural integrity of the GEL/ COL wound dressing
Ebrahim Zabihi, Roghayeh Pourbagher, Seyedali Seyedmajidi,
Volume 19, Issue 4 (12-2022)
Abstract
The optimization of biomaterials biodegradation rate similar to tissue regeneration, is one of the main
goals in the field of tissue engineering. However, the necessity to assess their possible toxicity is always considered.
The aim of this study was cytotoxicity and genotoxicity evaluation of fluorapatite/bioactive glass (FA/BG)
nanocomposite foams with two various weight ratios to determine the optimal composition. Nanocomposite foams
were made by gel-casting method with FA and BG as precursors in two weight ratios (A and B). Nanocomposite
foam extracts (CFEX) were prepared by shaking 100 mg/mL of each foam in a complete culture medium for 72 h in
a shaker incubator at 120 rpm/37ºC. Saos-II cells were exposed to different concentrations of CFEXs for 24 and
48 h and then cytotoxicity and genotoxicity were evaluated by MTT and comet assay, respectively. Based on the MTT
assay results after 24 h exposure, CFEX A at concentrations ≥75% and CFEX B at concentrations ≥50% had a
cytotoxic effect, while after 48 h, both CFEXs showed similar cytotoxicity at concentrations ≥25%. According to the
result of the comet assay, DNA damage increased with the increase of CFEXs concentration and exposure time.
Both CFEXs showed significantly higher comet tails elongation scores at concentrations ≥50% and ≥25% after 24
and 48 h exposure, respectively. Both composite foams could be considered as a non-toxic candidate for tissue
engineering at concentrations <25% which was less than FA50%/BG50% composite. Therefore, the composite with
equal FA/BG proportion has priority if similar results are obtained in in vivo complementary experiments.
Ines Dhifallah, Faten Rhouma, Imen Saafi, Jamila Bennaceur, Wafa Selmi, Wissem Dimessi, Radhouane Chtourou,
Volume 21, Issue 0 (3-2024)
Abstract
In this study, a novel three-step method for the synthesis of ZnO and branched ZnO microrods was developed. Numerous techniques were used to analyze the obtained samples: photoluminescence (PL) spectroscopy, raman spectroscopy, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), ultraviolet-visible spectroscopy (UV-visible) and X-ray diffraction (XRD). The XRD study and Rietveld refinement confirmed that the synthesized samples have the hexagonal wurtzite structure of ZnO without any impurity with the P63mc space group. To further verify our experimental results, structural parameters were calculated by First Principles Density Functional Theory (DFT) calculations and compared with experimental ones. A small decrease in the unit cell volume following the branching process was observed by the DFT calculations and Rietveld refinement results. Raman spectra showed peaks corresponding to the phonon modes of hexagonal wurtzite ZnO, which was consistent with the results of XRD and Rietveld refinement. SEM confirmed that ZnO and BZnO samples have hexagonal rod and branched rod shapes. BZnO showed stronger green PL emission but lower overall PL intensity compared to ZnO. The reduced photoluminescence (PL) intensity across all frequencies indicates enhanced separation of the photogenerated electron-hole pairs in branched ZnO (BZnO) due to decreased recombination.
