Synthesization of organic-inorganic hybrid nanostructures by green chemistry method using gelatin extract from the skin of rainbow trout (Oncorhynchus mykiss) and investigation of the synthesis mechanism and antimicrobial properties

In the current technological landscape, nanotechnological products are widely utilized in a multitude of fields due to their high efficiency, stability, and high surface-to-volume ratio. Nanotechnology offers numerous advantages, including the development of novel food products in the food industry, the enhancement of nutritional value in foods, the detection of pathogens, and the monitoring of food quality. With the advent of nanotechnology applications, traditional packaging techniques will be superseded by smart packaging. In this manner, the signs of food spoilage will be identified in advance, thereby ensuring food safety and shelf life. The objective of this study is to investigate the effect of different solvents (water, ethanol, and chloroform) and different copper concentrations (0.5 mM, 2 mM, 4 mM, and 5 mM) on the morphology of copper hybrid nanoflowers (Cu-HNF) using gelatin obtained from fish (rainbow trout) skin. In this study, metallic nanostructures (Cu-HNFs and Ag-NPs) were synthesized for the first time using gelatin obtained from fish skins, which are commonly referred to as "rainbow trout waste." Furthermore, in this study, biopeptides in gelatin obtained from rainbow trout skin were employed as a stabilizing and reducing agent for copper and silver metals. The antimicrobial properties of the flower-shaped hybrid nanostructures (Cu-HNF) and silver nanostructures (Ag-NPs) synthesized based on gelatin were characterized and compared. To characterize the obtained Cu-HNF and Ag-NPs, a series of analytical techniques were employed, including X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-VIS Spectrophotometer, Energy Dispersive X-Ray Spectroscopy (EDS) and Fourier Transform Infrared Spectrometry (FT-IR). The obtained metallic nanostructures were tested against Escherichia coli O157:H7 (ATCC 43895), Staphylococcus aureus (ATCC 23235), Listeria monocytogenes (ATCC 35152) and Salmonella enterica (ATCC 35664). The results demonstrated that Ag-NPs exhibited a significant effect on all bacteria, while no effect was observed for Cu-HNFs. It was observed that the structures exhibited different morphologies at varying copper concentrations utilized in the synthesis of Cu-HNFs and distinct solvents in which gelatin was dissolved. This study represents the inaugural documentation in the literature of the synthesis of Cu-HNF and Ag-NPs structures in an organic-inorganic composite utilizing fish skin, a byproduct of aquaculture processing.