Objective: The objective of our study was to synthesize and characterize silica–copper nanomaterials and to evaluate their biological properties (antibacterial, redox, cytotoxic, and ecotoxic) for potential applications. Methods and Results: Si/Cu-based materials were prepared by a sol–gel method. They were characterized by XRD, UV-Vis, and SEM-EDS. The antibacterial activity of the materials was evaluated against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium), and yeasts (Candida albicans, Saccharomyces cerevisiae). The nanomaterial that was calcined at 500 °C exhibited greater antibacterial efficacy compared to the gel form. S. typhimurium demonstrated the highest susceptibility, whereas S. aureus and P. aeruginosa were the most resistant of the tested bacteria. Both yeasts exhibited comparable sensitivity (MBC = 1.0 mg/mL). The redox activity of both nanomaterials was tested at pH 7.4 (physiological) and 8.5 (optimal) by the activated chemiluminescent method. The nanocomposites significantly inhibited the free-radical and ROS generation. This presents them as redox regulators in living systems. The cytotoxic effects in normal BEAS-2B and tumor A549 human cell lines were assessed microscopically and by the cell viability neutral red uptake assay, CC₅₀ being evaluated. The observed effects suggest moderate, similar cytotoxicity in both cell lines. The ecotoxicity study using Daphnia magna showed an LC₅₀ of ~7–8 mg/L about Si/Cu/500. The LC₅₀ for Si/Cu (gel) was lower than 0.25 mg/L, indicating an increase in toxicity with increased exposure time. Conclusions: Possible applications of the newly synthesized nanomaterials include antimicrobial coatings, drug delivery systems, antioxidant additives in various formulations, and water purification.

This study investigates the synthesis, characterization, antimicrobial performance, and redox activity of sol–gel–derived TiO₂/TeO₂/CuO powders. The as-prepared gel with the nominal composition 80TiO₂/10TeO₂/10CuO was subjected to thermal treatment at 400 °C and 600 °C for 2 h, resulting in the formation of composite materials at both temperatures. By UV-Vis spectroscopy, it has been found that CuO is responsible for the red shifting of the absorption edge. The SEM-EDS analysis verified the elemental composition of the synthesized powders. The antimicrobial activity of the heat-treated powders was proved against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, representative Gram-negative and Gram-positive bacteria frequently associated with hospital-acquired infections and antibiotic resistance. At physiological pH, the 600 °C-treated sample exhibited strong prooxidant properties, supporting antimicrobial activity. At alkaline conditions, the nanomaterials were effective against superoxide radicals. The variation in oxidation with changes in pH is indicative of the potential for controlled application. Antimicrobial activity was assessed through minimum inhibitory concentration (MIC) assays and spot and luminescent tests, providing both quantitative and qualitative evaluations.