Biosynthesis of CuO nanoparticle using leaf extracts of Ocimum lamiifolium Hochst. ex Benth and Withana somnifera (L) Dunal for antibacterial activity

Nanotechnology is becoming a promise for scientific advancement nowadays in areas like medicine, consumer products, energy, materials, and manufacturing. Copper oxide nanoparticles (CuO NPs) were synthesized using Ocimum lamiifolium Hochst. ex Benth and Withana somnifera (L) Dunal leaf extract via green synthetic pathway. The leaf of O. lamiifolium and W. somnifera were known to have strong antibiotic and antioxidant properties arising due to the presence of various secondary metabolites, including, flavonoids, alkaloids, saponins, tannins, cardiac glycosides, and phenolic compounds which serve as reducing, stabilizing, and capping agents for the CuO-Nanoparticles (NPs) synthesized. The biosynthesized CuO NPs were characterized based on Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and scanning electron microscopy. O. lamiifolium and W. somnifera leaf extract mediated synthesis could produce CuO NPs with average crystallite size of 15 nm and 19 nm, respectively. The biosynthesized CuO-NPs were further examined for antibacterial activity with Gram-positive (S. aureus) and Gram-negative bacteria (E. coli and P. aeruginosa). The GZDK-CuO NPs synthesized using W. somnifera leaf extract inhibited the growth of E. coli. and P. aeruginosa largely in comparison to S. aureus. Whereas the DMAZ-CuO NPs synthesized with the help of O. lamiifolium leaf extract showed higher bacterial inhibition on E. coli compared to S. aureus and P. aeruginosa. The minimum inhibitory concentration (MIC) values of both types of NPs are also assessed on all three pathogens. The newly biosynthesized nanoparticles, thus, were found to be optional materials for inhibiting the growth of drug- resistant bacterial pathogens.

Illuminating new possibilities: Effects of copper oxide nanoparticles on gastrointestinal adenocarcinoma cells in hypoxic condition

Cancer remains a major global health concern, necessitating the development of novel therapeutic approaches. Hypoxia is a common characteristic of solid tumors that plays a critical role in tumor progression, making it a prime target for anticancer therapies. This study aimed to determine the effects of copper oxide nanoparticles (CuONPs) on human gastrointestinal cancer cells in hypoxic condition for the first time. Toxicity of CuONPs was evaluated on human colon and gastric adenocarcinoma cells and normal fibroblasts by alamarBlue assay. Real-time polymerase chain reaction (PCR) was performed to study the effects of CuONPs on genes involved in cell apoptosis. To elucidate the molecular mechanisms underlying the effects of CuONPs in hypoxic condition, molecular docking was conducted on HIF-1α. Results revealed dose- and cell-type-dependent toxic effects of CuONPs, as a more significant (p < 0.0001) decrease in viability of LoVo cells (23 %) was observed compared to MKN-45 and HDF cells. In addition, CuONPs significantly (p < 0.0001) reduced LoVo cell viability down to 30.2 % in hypoxic condition. Gene expression analysis revealed significant (p < 0.0001) overexpression of P53 and BAX but downregulation of BCL-2 and CCND1 after treatment with CuONPs. Molecular docking indicated the preferable binding of CuONPs to the HIF-1α PAS-B domain through interaction with 15 residues with -4.8 kcal/mol binding energy. Our findings open up new possibilities for modulating HIF-1 activity and inhibiting hypoxia-induced tumor progression.

Copper(II) Oxide Nanoparticles Embedded within a PEDOT Matrix for Hydrogen Peroxide Electrochemical Sensing

The aim of this study is the preparation of nanostructured copper(II) oxide-based materials (CuONPs) through a facile additive-free polyol procedure that consists of the hydrolysis of copper(II) acetate in 1,4-butane diol and its application in hydrogen peroxide sensing. The nonenzymatic electrochemical sensor for hydrogen peroxide determination was constructed by drop casting the CuONP sensing material on top of a glassy carbon electrode (GCE) modified by a layer of poly(3,4-ethylenedioxythiophene) conducting polymer (PEDOT). The PEDOT layer was prepared on GCE using the sinusoidal voltage method. The XRD pattern of the CuONPs reveals the formation of the monoclinic tenorite phase, CuO, with average crystallite sizes of 8.7 nm, while the estimated band gap from UV-vis spectroscopy is of 1.2 eV. The SEM, STEM, and BET analyses show the formation of quasi-prismatic microaggregates of nanoparticles, with dimensions ranging from 1 µm up to ca. 200 µm, with a mesoporous structure. The developed electrochemical sensor exhibited a linear response toward H₂O₂ in the concentration range from 0.04 to 10 mM, with a low detection limit of 8.5 μM of H₂O₂. Furthermore, the obtained sensor possessed an excellent anti-interference capability in H₂O₂ determination in the presence of interfering compounds such as KNO₃ and KNO₂.