Structural and Biological Properties of CuO Nanoparticles Prepared Under Ultrasonic Irradiation

Potential antimicrobial, antidiabetic, catalytic, antioxidant and ROS/RNS inhibitory activities of Silybum marianum mediated biosynthesized copper oxide nanoparticles

Use of medicinal plants for the biosynthesis of nanoparticles offers several advantages over other synthesis approaches. Plants contain a variety of bioactive compounds that can participate in reduction and capping of nanoparticles. Plant mediated synthesis has the leverage of cost effectiveness, eco-friendly approach and sustained availability. In the current study Silybum marianum, a medicinally valuable plant rich in silymarin content, is used as a reducing and stabilizing agent for the fabrication of nanoparticles. Biosynthesized CuO-NPs were characterized using High Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS) techniques. Characterization revealed that CuO-NPs having a crystalline structure showed spherical morphology with an average size of 15 nm. HPLC analysis demonstrated conjugation of various silymarin components, especially the presence of silybin A (705.06 ± 1.59 mg g^-1 DW). CuO-NPs exhibited strong bactericidal potency against clinically important pathogenic bacterial strains e.g. Enterobacter aerogenes and Salmonella typhi with an inhibition zone of 18 ± 1.3 mm and 17 ± 1.2 mm, respectively. Synthesized nanoparticles indicated a dose dependent cytotoxic effect against fibroblast cells exhibiting a percentage cell viability of 83.60 ± 1.505% and 55.1 ± 1.80% at 25 μg mL^-1 and 100 μg mL^-1 concentration, respectively. Moreover, CuO-NPs displayed higher antioxidant potential in terms of (TAC: 96.9 ± 0.26 μg AAE/mg), (TRP: 68.8 ± 0.35 μg AAE/mg), (DPPH: 55.5 ± 0.62%), (ABTS: 332.34 μM) and a significant value for (FRAP: 215.40 μM). Furthermore, enzyme inhibition assays also exhibited excellent enzyme inhibition potential against α-amylase (35.5 ± 1.54%), urease (78.4 ± 1.26%) and lipase (80.50.91%), respectively. Overall findings indicated that biosynthesized CuO-NPs possess immense in vitro biological and biomedical properties and could be used as a broad-spectrum agent for a wider range of biomedical applications.

Application of nanostructures as antimicrobials in the control of foodborne pathogen

Foodborne pathogens are the main cause of human foodborne diseases and pose a serious threat to food safety. The control of them has always been a significant issue in food industry. With good biocompatibility and stability, nanomaterials display excellent bactericidal properties against many kinds of bacteria. In this review, the generation and application of nanostructures as antibacterial in the control of foodborne pathogens was summarized. The antibacterial effects of photocatalytic and contact bacteriostatic nanomaterials agents were mainly introduced. The influence factors and mechanisms of nanomaterials on the inactivation of foodborne pathogens were displayed. The photocatalytic nanostructured bacteriostatic agents can produce reactive oxygen species (ROS) and lead to charge transfer, which result in damaging of cell wall and leakage of small molecules under light irradiation. In addition, metals and metal oxide nanoparticles can kill bacterial cells by releasing metal ions, forming ROS and electrostatic interaction with cell membrane. Besides, the synergistic action of nanoparticles with natural antibacterial agents can improve the stability of these agents and their bactericidal performance. These current researches provided a broader idea for the control of microorganisms in food.

PVP and PEG doped CuO nanoparticles are more biologically active: Antibacterial, antioxidant, antidiabetic and cytotoxic perspective

Search for biologically active nanoparticles is prerequisite for biomedical applications. CuO nanoparticles synthesized by co-precipitation method are capped by polyethylene-glycol (PEG) and polyvinyl-pyrrolidone (PVP) on the surface by simple adsorption. Physical and chemical properties carried out by SEM, XRD and FTIR confirm nanometer in size and efficient capping of PVP and PEG on CuO NPs. Biological assays reveal higher activities of CuO-PEG and CuO-PVP as compared to the uncapped CuO nanoparticles. CuO-PEG shows better antitumor activity against Streptomyces as compared with CuO-PVP and CuO NPs. Both the capped NPs are significantly active for α-amylase inhibition assay. CuO-PVP demonstrates significantly better activity against bacterial strains followed by CuO-PEG and uncapped CuO. PVP coated CuO NPs also shows strong DPPH based free radical scavenging activity, total reducing power potential, total antioxidative potential and also carries flavonoid and phenolics properties determines to querecetin and gallic acid equivalence, respectively. It can be concluded that PVP and PEG capped CuO NPs are more capable to be used in biomedical applications as drug and diagnostic carrier molecules.