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Although carbon nanoparticles or quantum dots (C-dots) have been studied extensively for a variety of applications (e.g., photocatalysis, metal ion sensing, antibacterial, cell labeling), a greener synthetic method is highly indispensable. Herein, we report a facile one-step hydrothermal carbonization approach for the synthesis of fluorescent blue/green C-dots using oyster mushroom (Pleurotus species). First, we demonstrate the application of these C-dots as a colorimetric sensor for toxic metal ions detection such as heavy metal Pb2+ ions with the limit of detection (LOD) and limit of quantification (LOQ) of 58.63 μM and 177.69 μM, respectively. Second, we show the application of C-dots as a promising fluorescent probe for DNA recognition through the electrostatic intercalative interaction between ctDNA and C-dots. Third, we demonstrate the efficient antibacterial activity of C-dots against three bacterial strains (Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa). Finally, the anticancer activity of C-dots against MDA-MB-231 breast cancer cells is demonstrated.

Cerium oxide nanoparticles showed negligible local effects, low systemic toxicity and genotoxicity via implantation route.

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A cobalt(III) complex, [Co(L)]Cl (complex 1 , where L = 1,8-[ N , N -bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane) with distorted octahedral geometry has been synthesized and characterized using various spectroscopic techniques. The structure of the ligand has remarkably rich hydrogen intermolecular interactions such as H···H, H···C/C···H, and H···O/O···H that vary with the presence of the metal ion, and the structure of complex 1 has Cl···H interactions; this result has been proved by Hirshfeld surface and two-dimensional (2D) fingerprint maps analyses. The complex exhibits a quasi-reversible Co(III)/Co(II) redox couple with E 1/2 = −0.76 V. Calf thymus DNA (CT DNA) binding abilities of the ligand and complex 1 were confirmed by spectroscopic and electrochemical analyses. According to absorption studies, the ligand and complex 1 bind to CT DNA via intercalative binding mode, with intrinsic binding strengths of 1.41 × 10 3 and 8.64 × 10 3 M –1 , respectively. A gel electrophoresis assay shows that complex 1 promotes the pUC19 DNA cleavage under dark and light irradiation conditions. Complex 1 has superior antimicrobial activity than the ligand. The cytotoxicity of complex 1 was tested against MDA-MB-231 breast cancer cells with values of IC 50 of 1.369 μg mL –1 in the dark and 0.9034 μg mL –1 after light irradiation. Besides, cell morphological studies confirmed the morphological changes with AO/EB dual staining, reactive oxygen species (ROS) staining, mitochondria staining, and Hoechst staining on MDA-MB-231 cancer cells by fluorescence microscopy. Complex 1 was found to be a potent antiproliferative agent against MDA-MB-231 cells, and it can induce mitochondrial-mediated and caspase-dependent apoptosis with activation of downregulated caspases. The biotoxicity assay of complex 1 on the development of Artemia nauplii was evaluated at an IC 50 value of 200 μg mL –1 and with excellent biocompatibility.