In the context of the proposed work, two different amino acids (Glycine, Phenylalanine) have interacted with copper ions in a phosphate buffer (PBS) in place of enzymes. This interaction resulted in the nucleation of copper phosphate crystals and the formation of flower-shaped amino acid-copper hybrid nanostructures (AA-hNFs), which grew through self-assembly. While Cu (II) ions in the structure of AA-hNFs were used as Fenton's agent for the catalytic activity. SEM, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy measurements were used to define the AA-hNFs' characterisation. The peroxidase-like activities of AA-hNFs were investigated by UV/VIS spectrophotometer. Metal nanoparticles have peroxidase-like activity. A class of enzymes known as peroxidases is able to catalyze the conversion of hydrogen peroxide into hydroxyl radicals. These radicals also take part in electron transfers with substrates, which results in color during oxidation. When cupric oxide nanoparticles are added to the peroxidase substrate while H2 O2 is present, a blue color product with a maximum absorbance at=652 nm can result, demonstrating the catalytic activity of a peroxidase. The morphology and composition of AA-hNFs were carefully characterized and the synthesized parameters were optimized systematically. Results showed that the nanoparticles were dispersed with an average diameter of 7-9 μm and indicated a uniform flower shape. The results of the investigation are anticipated to significantly advance a number of technical and scientific sectors.
Materials in nano size called “nanomaterials” convey novel and enhanced properties based upon their size, shape, morphology, and component and have been intensively employed in a variety of scientific and industrial fields. Specifically, nanomaterials have been exposed to humans, plants, and animals, so toxicity of nanomaterials is a crucial issue that must be investigated and documented when exposed to living organisms. Researchers have focused on various surfactants, surface engineering strategies, and synthesis methods to create less harmful or biocompatible nanomaterials. This present review comprehensively and comparatively focuses on most rapid growth and exciting research on a variety of nanomaterials, their synthesis methods, and nanomaterial surface designing strategies.
We report synthesis of monodispersed, stable, and colloidal gold nanoparticles (Au NPs) using anthocyanin-riched red raspberry (Rubus idaeus), strawberry (Fragaria ananassa), and blackberry (Rubus fruticosus) extracts as functions of concentration of HAuCl4·3H2O and berries extract, reaction time, and reaction pH values (pHs) and demonstrate their unique stability in highly concentrated salt (sodium chloride, NaCl) solutions. The catecholamine group of anthocyanin molecules give preferential coordination reaction with gold ions (Au3+) for creating anthocyanin-Au3+ complexes, which may lead to initiation of nucleation for seed formation, and then, oxidation of catecholamine results in a flow of electrons from anthocyanins to Au seeds for anisotropic growth. Finally, the surface of the Au NPs is saturated with anthocyanins, and formation of monodispersed and stable Au NPs with narrow size distribution is completed. We also report the effects of some experimental parameters including concentrations of Au3+ ions and barrier extracts, reaction time, and pHs on formation of the Au NPs with rational explanations. The long-term colloidal stability of the Au NPs in the 400 mM NaCl solution was comparatively studied with commercial Au NPs (citrate capped). As results show that anthocyanin-riched berry extracts directed Au NPs we proposed here can be considered as promising and safe tools for biomedical applications owing to their highly much colloidal dispersibility and salt tolerance properties.
In this work, plant extract–metal ions hybrid nanoflowers (HNFs) were synthesized and their catalytic and antimicrobial properties were examined. While the sweet and sour lemon peel extract (acquired in boil water) and its primary elements were engaged as organic elements in the creation of NFs, copper (II) ions (Cu2+) were the inorganic element. Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) spectroscopy, and Fourier Transform Infrared Spectrometry (FT-IR) were examined to characterize the structures of the NFs. The structural examination showed that the existence of Cu–O and Cu–N bonds in NFs can be a sign of the creation of NFs. Antimicrobial activities of the NFs were systematically studied against Candida albicans (ATCC 90028), Staphylococcus aureus (ATCC 25923), and Escherichia coli (ATCC 25922) with broth microdilution and short time-kill assay. The peroxidasemimicking activity based on the NFs' Fenton-like response mechanism was assessed against guaiacol in the presence of H2O2. The findings have shown that plant extract-based hybrid NFs technology is promising and can find prospective applications in numerous technical areas.
Abstract Foodborne infections are one of the most important problems in the protection of human health. Bacillus cereus and Salmonella enteritidis as the most common foodborne pathogens are the main cause of food poisoning. Due to the inadequacy of traditional antibiotics, biofilm formation and increase in resistant species, the control of the pathogen growth is a quite challenging issue. Recently, Black Phosphorus (BP) nanosheets as a rising star 2D semiconductor, has attracted great attention due to their specific surface interface interactions. Photo‐activated BP‐based nanocomposites could trigger the release of inorganic nanoparticles, creating superior antibacterial functions. In this work, NIR light‐induced antibacterial activities of pristine BP nanosheets, BP/Ag and BP/Au nanocomposites were tested on Bacillus cereus and Salmonella enteritidis and both of BP/Au or BP/Ag exhibited superior growth inhibition efficiencies compared to pristine BP nanosheets due to the active sites for physical contact with bacterial membranes as well as production of ROS. SEM analysis proved that BP‐based nanocomposites create physical membrane damages. Antibiofilm activities of the nanocomposites were also examined, which is higher than BP nanosheets alone. Accordingly, due to the sharp edges, NIR‐triggered photothermal effect and Schottky interaction of nanocomposites the biofilm structure was mechanically damaged. This work provides an idea to control the growth of bacteria by BP‐based nanocomposites, which have the potential to be used in large‐scale approaches as an alternative to antibiotics.
Due to its distinct, atypical features and possible applications, three-dimensional (3D) hierarchical nanoflowers have sparked considerable interest. Copper (II) ions were employed as inorganic components in this study, whereas various extracts from Aspergillus terreus and their extracted main components were used as organic components. Extracts from A. terreus and its isolated principal component molecules can first form complexes with copper ions, and these complexes subsequently become nucleation sites for primary copper phosphate crystals, showing interactions using an easy and successful self-assembly template synthesis technique. Therefore, the process results in the formation of 3D nanoflowers among the A. terreus extract and its remoted important additives in addition to copper ions, ensuing in a completely unique round flower-like shape containing loads of nanopetals under the most excellent conditions along with pH, attention of organic–inorganic additives, temperature, and the quantity of copper nitrate on nanoflower formation. Furthermore, A. terreus and its isolated major components, Cu3(PO4)2 nanoflowers, seemed to have a remarkable antibacterial effect. Our findings highlight the benefits of nanoflowers made with A. terreus and its isolated secondary metabolites of inorganic structures, which could be used in industrial biocatalysts, biosensors, and environmental chemistry.
Abstract
Packaged fresh food is one of the factors that trigger the shelf life negatively; It is at the forefront that the liquid percolated by food accumulates inside of the package, accelerating chemical and microbial spoilage and finalized with reducing food quality. In order to prevent the accumulation of liquid in the package, the absorbent pads disposed therein are partially presented as a solution of the problem. The aim of this research is to enrich absorbent pads with naturally derived antioxidants to make them more functional and extend the shelf life of food. It is also possible to easily inform the consumer about the quality of food with the expected color change in the absorbent pad. This is the first study by making use of extract of red cabbage plant and preparing absorbent pads by combining with cellulose for examination of color change on the pad through microbial growth by time. In this study, 25 gr of trout sample were used to observe color change on the fresh prepared food pads. For each pad were prepared using 5 ml of red cabbage extract (1:1 ratio) and dried. Salmonelle typhi ATCC 14028, Escherichia coli ATCC 25893, and Staphylococcus aureus 25922 were syringed to each fish sample to make the microbial growth faster. After 12 hours color change on the pad was observed with a naked eye that purple red cabbage color was changed to greenish- blue. However, pH measurements also showed a parallel result with the color change and the pH of the fresh fish samples was 6.3 then this value increased from 6.3 to 7.9 in the day-3.
