Cyanobacteria, as one of the largest groups of phototrophic bacteria, have a high potential as an excellent source of fine chemicals and bioactive compounds, including lipid-like compounds, amino acid derivatives, proteins, and pigments. This study aimed to synthesize ZnO nanoparticles using the cell extract of the cyanobacterium Nostoc sp. EA03 (CEN-ZnO NPs) through a rapid and eco-friendly approach. The biosynthesized nanoparticles, CEN-ZnO NPs, were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential measurement, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), FTIR, SEM, TEM, and EDX spectroscopy. The UV-Vis spectrum showed an absorption peak at 370 nm. The star-shaped CEN-ZnO NPs, as observed in the TEM and SEM images, had an average diameter of 50-80 nm. MIC and MBC values for E. coli, P. aeruginosa and S. aureus, were determined to be, respectively, 2000, 2000, and 64 mg ml À1 , and 2500, 2500 and 128 mg ml À1 . Further analysis through confocal laser scanning microscopy (CLSM) provided the observable confirmation that the CEN-ZnO NPs stunted the bacterial growth, preventing the formation of exopolysaccharides. The AFM analysis of surface topography of bacterial biofilm samples treated with CEN-ZnO NPs showed a rugged topography in some parts of the biofilm surface, indicating the destruction of biofilms. In contrast, in the untreated control samples, the structured biofilms were flat and prominent. MTT assay indicated that CEN-ZnO NPs had less cytotoxicity on the MRC-5 lung fibroblast cells compared with the cancerous treated A549 cells. As the concentration of the CEN-ZnO NPs increased, the amount of ROS produced in the tested bacterial strains also increased. Analyzing the data obtained from flow cytometry showed that the higher concentrations of CEN-ZnO NPs lead to a reduction in the viability of P. aeruginosa PAO1, E. coli and S. aureus. The biosynthesized ZnO nanoparticles using Nostoc cell extracts exhibited different attributes, inspiring enough to be considered for further investigation.

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In this research, an efficient and simple method has been reported for the preparation of spiro[indene[1,2‐d]pyrimidine‐one derivatives through the multi‐component reactions of cyclic ketones, urea/thiourea/guanidine and 1,3‐indandion in the presence of NiCo2O4@Ni(BDC) (terephthalic acid) nanocatalyst. In this method, the products were obtained in short reaction times and excellent yields. The prepared metal‐organic frameworks have been fully analyzed by fourier transform infrared spectrophotometry (FT‐IR), field emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDX), thermogravimetric analysis (TGA),vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), N2 adsorption‐desorption by Brunauer–Emmett‐Teller (BET) and X‐ray diffraction (XRD)analysis. In addition, all of the synthesized pyrimidines screened against different pathogenic bacteria including Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and also their antifungal activity were investigated against Candida albicans.

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