Structure-Function Assessment of Wheat Gluten Metallic Nanoparticles Composites for Applications in Therapeutics and Material Industry

Abstract

Nanoparticles have attracted much attention due to their unique and adaptable properties. Metallic nanoparticles (NPs) are of particular interest due to their non-toxic role in biological systems, biocompatibility, and ease of fabrication. Nanocomposites are an exciting multidisciplinary field that combines biological science, materials science, and nanotechnology, with significant implications for medical science. Natural biopolymers, such as wheat gluten, are advantageous in this regard as they are biodegradable, bioavailable, and non-toxic, making them an ideal choice for production of composites with nanomaterials. With this in mind, the present work was focused on the syntheses of metallic nanoparticles i.e. α Fe2O3, ZnO, and Ag NPs, and their incorporation into biopolymeric wheat gluten matrix, resulting in nanocomposite materials suitable for use in the transdermal drug delivery for burn wound treatment and in the smoke filtration system for pollutant adsorption. Following the co-precipitation route by chemical synthesis, the successful preparation of rhombohedral iron oxide (α-Fe2O3)/hematite nanoparticles, wurtzite ZnO NPs, and face centered cubic Ag NPs under different light regimes was carried out to reveal the effect of changing in the wavelength of photons. The XRD spectra showed the phase purity with an increase in the size of Fe2O3 NPs from 20.61nm to 28.87nm was observed with the increase in the wavelength of light. A similar trend was also observed for the average size of ZnO NPs (17.11nm – 22.56 nm) and Ag NPs (16nm-25nm) synthesized under different light conditions. EDX showed the main elements in synthesized NPs in different wt% as Fe and O in hematite NPs, Zn and O in ZnO NPs, and Ag in Ag NPs. The FTIR spectra present the characteristic peaks in the synthesized nanoparticles indicating the successful synthesis of hematite, zinc oxide, and silver nanoparticles. The nanostructure morphology by SEM showed that different light conditions lead to greater versatility in the formation of well-defined Fe2O3, ZnO, and Ag NPs. Hematite (α-Fe2O3) NPs showed significant antioxidant potential and enzyme inhibitory effects on urease, lipase, and alpha-amylase. Among them, BLNPs showed the highest metal chelating capacity (41.48%), while GLNPs were the most significant inhibitors of urease (91.5%) and lipase (89.2%) enzymes, and α-Fe2O3 NPs synthesized in the dark showed excellent peroxidase-like activity. The photo-induced ZnO NPs exhibited significant biological activities as the DL-ZNPs and GL-ZNPs showed the highest antioxidant potential xxi among all the tested ZnO NPs. While significant enzymes inhibitory activities and peroxidase like activity were shown by ZnO NPs synthesized under LED environment. Among the photoexcited silver nanoparticles (SNPs), DL-SNPs showed the highest antioxidant activity, enzyme inhibition, and peroxidase-like activities. Blue light and daylight ZNPs and SNPs induced the expression of bacterial resistance against MRSA and P. aeruginosa. However, in α-Fe2O3 NPs, green and red light NPs also significantly inhibited the growth of these bacterial strains. Nanoscale metallic particles are excellent functional fillers. Nanocomposite films were developed by incorporating NPs (α-Fe2O3, ZnO, and Ag) into a biodegradable wheat gluten matrix, and the poly (vinyl pyrrolidone) (PVP), poly (ethylene glycol) (PEG), and poly (vinyl alcohol) (PVA) as crosslinkers. The interfacial interaction between the NPs/WG composite (abbreviated as WG/HNPs, WG/ZNPs, and WG/AgNPs), and the crosslinker matrix, significantly affected the final film properties which were investigated by physiochemical and biological techniques. From the XRD and FTIR patterns, the intensities and positions of the refracted peaks indicate the successful crosslinking between NPs, WG, and crosslinkers. SEM micrographs demonstrate the physical entrapment of NPs into the WG polymer network resulting in the altered morphology of nanocomposite films. The swelling capacity of nanocomposite films was tested at acidic, neutral, and basic pH and was found highest in WG/PVP/ZnO (138%) at pH 5, WG/PVA/Ag (371%) at pH 7, WG/PEG/Ag (389.33%) at pH 9. The crosslinked complex of NPs and wheat gluten polymer may result in significant electrostatic interactions which promote the slow and progressive release of NPs/ions from nanocomposite films. The disc diffusion and micro broth antibacterial tests revealed that Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus were sensitive to nanocomposite films and pure NPs. The nanocomposite films also exhibited enhanced antioxidant potentials compared to the respective reference films, pure NPs, and WG. These antioxidant potentials were determined by their ability to defend the biological system against reactive oxygen species with electron-donating capacity and prevention of chain initiation reactions, etc. The physiochemical and biological characteristics of nanocomposite films make them suitable for application in biological systems. Furthermore, the study reports the fabrication and evaluation of zinc or silver NPs doped with vitamin A or E nanocomposite that were incorporated into wheat gluten (WG) films. The chemical structure, phase purity, and morphological features confirmed the successful doping of NPs with vitamins A and E and their interaction with WG during film xxii casting. The maximum swelling response was observed by vitamin-doped ZnO/Ag NPs based WG films than their respective control films while slow release of vitamins and NPs from vitamin-doped films was observed up to 24 hr. WG films doped with either ZnO or Ag NPs, and vitamin A or E showed significant antioxidant and antibacterial potential. The vitamin doped ZnO/Ag NPs based WG films showed wound contraction within 14 days during in vivo burn wound healing experiments on mice models. The rates of wound healing, re epithelialization, collagen deposition with fibroblast regeneration, adipocytes, and hair follicle development were observed by visual and histopathological examination. The study revealed that vitamin A or E doped ZnO or Ag NPs and fabricated in WG films can be efficiently used against burn wound treatment due to their physiochemical and biological properties. In addition, the biocompatible and biodegradable nature make these films more prone to mankind's maneuver for initial protection and healing remedy. WG/PVA composite nanofibers sheets incorporated by zinc, silver, and iron nanoparticles were successfully fabricated by the electrospinning technique. Scanning electron microscopy demonstrates the beadless, self-assembled, and rounded morphology of WG/PVA/NPs nanofibers with scattered NPs in the fibers sheets. However, WG/PVA fibers yield fewer beads in the fibrous structure. Fourier Transform Infrared spectroscope (FTIR) spectroscopy was used for studying the WG composite nanofiber’s chemical structure, functional groups, and compositional changes in nanofibers before and after the smoke filtration process. The WG composite nanofibers filters outperformed local cigarette filters in terms of their capability to absorb and filter smoke pollutants. WG/PVA/Ag demonstrated the highest filtration efficiency (42.6%) followed by WG composite Zn (34.5%) and Fe nanofibers (32.2%). These WG/NPs-based nanofiber filters can be potential candidates for pollutant removal. From this study, it is concluded that the versatility and effectiveness of the WG-based nanocomposite films and nanofibrous sheets make them valuable assets in numerous fields with potential implications for the advancement of various technologies