{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:00:58Z","timestamp":1787029258157,"version":"build-2736575974"},"reference-count":37,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T00:00:00Z","timestamp":1766448000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Sofia University, \u201cSt. Kliment Ohridski\u201d, Bulgaria","award":["80-10-134\/03.06.2025"],"award-info":[{"award-number":["80-10-134\/03.06.2025"]}]},{"name":"National Recovery and Resilience Plan of the Republic of Bulgaria","award":["BG-RRP-2.004-0008-C01"],"award-info":[{"award-number":["BG-RRP-2.004-0008-C01"]}]},{"name":"National Recovery and Resilience Plan of the Republic of Bulgaria","award":["76-123-661"],"award-info":[{"award-number":["76-123-661"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>Objective: The objective of our study was to synthesize and characterize silica\u2013copper 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\u2013gel 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 \u00b0C 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\u20138 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.<\/jats:p>","DOI":"10.3390\/ph19010035","type":"journal-article","created":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T14:05:22Z","timestamp":1766498722000},"page":"35","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Antibacterial, Redox, Cytotoxic, and Ecotoxic Properties of New Sol\u2013Gel Silica-Copper-Based Materials"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5964-0609","authenticated-orcid":false,"given":"Iliana","family":"Ivanova","sequence":"first","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-5492-9897","authenticated-orcid":false,"given":"Lilia","family":"Yordanova","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3452-908X","authenticated-orcid":false,"given":"Lora","family":"Simeonova","sequence":"additional","affiliation":[{"name":"Department of Virology, Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 G. Bonchev Str., 1113 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miroslav","family":"Metodiev","sequence":"additional","affiliation":[{"name":"Department of Virology, Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 G. Bonchev Str., 1113 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4590-1553","authenticated-orcid":false,"given":"Elena","family":"Nenova","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Deyan","family":"Monov","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8644-6470","authenticated-orcid":false,"given":"Yoanna","family":"Kostova","sequence":"additional","affiliation":[{"name":"Institute of Metal Science, Equipment and Technologies with Hydro- and Aerodynamics Centre \u201cAcad. A. Balevski\u201d, Bulgarian Academy of Sciences, Shipchenski Prohod Str., 67, 1574 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7697-466X","authenticated-orcid":false,"given":"Albena","family":"Bachvarova-Nedelcheva","sequence":"additional","affiliation":[{"name":"Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iva","family":"Kirova","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Sofia University \u201cSt. Kliment Ohridski\u201d, 5 James Boucher Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5708-3482","authenticated-orcid":false,"given":"Elitsa","family":"Pavlova","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Sofia University \u201cSt. Kliment Ohridski\u201d, 5 James Boucher Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"544","DOI":"10.1016\/j.conbuildmat.2018.05.159","article-title":"Morphology, large-scale synthesis and building applications of copper nanomaterials","volume":"180","author":"Shah","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1016\/j.nano.2009.07.002","article-title":"Biological synthesis of metallic nanoparticles","volume":"6","author":"Thakkar","year":"2010","journal-title":"Nanomed. Nanotechnol. Biol. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"698","DOI":"10.1016\/j.ijleo.2019.02.046","article-title":"A sol\u2013gel approach to the synthesis of CuO nanoparticles using Lantana camara leaf extract and their photocatalytic activity","volume":"183","author":"Arunkumar","year":"2019","journal-title":"Optik"},{"key":"ref_4","first-page":"9","article-title":"A brief review on synthesis and characterization of copper oxide nanoparticles and their applications","volume":"1","author":"Singh","year":"2016","journal-title":"J. Bioelectron. Nanotechnol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"269","DOI":"10.3390\/hygiene3030020","article-title":"Antimicrobial nanomaterials: A review","volume":"3","author":"Ovezova","year":"2023","journal-title":"Hygiene"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Alabdallah, N.M., and Kotb, E. (2023). Antimicrobial activity of green synthesized silver nanoparticles using waste leaves of Hyphaene thebaica (doum palm). Microorganisms, 11.","DOI":"10.3390\/microorganisms11030807"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"102597","DOI":"10.1016\/j.cis.2021.102597","article-title":"Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: A review","volume":"300","author":"Abid","year":"2021","journal-title":"Adv. Colloid Int. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Ivanova, K., Bachvarova-Nedelcheva, A., Iordanova, R., Stoyanova, A., Petrova, P., Yordanova, L., and Ivanova, I. (2025). Synthesis, luminescent and antibacterial properties of sol-gel TiO2\/TeO2\/Nb2O5 powders. Materials, 18.","DOI":"10.3390\/ma18050946"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1186\/s12951-023-02093-w","article-title":"Powering mesoporous silica nanoparticles into bioactive nanoplatforms for antibacterial therapies: Strategies and challenges","volume":"21","author":"Li","year":"2023","journal-title":"J. Nanobiotechnol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"113053","DOI":"10.1016\/j.biopha.2022.113053","article-title":"Silica nanoparticles: Biomedical applications and toxicity","volume":"151","author":"Huang","year":"2022","journal-title":"Biomed. Pharmacother."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Bruckmann, F.d.S., Nunes, F.B., Salles, T.d.R., Franco, C., Cadon\u00e1, F.C., and Bohn Rhoden, C.R. (2022). Biological applications of silica-based nanoparticles. Magnetochemistry, 8.","DOI":"10.3390\/magnetochemistry8100131"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"105421","DOI":"10.1016\/j.tiv.2022.105421","article-title":"Mesoporous nanosilica: A thromboprotective nanomaterial for biomedical applications","volume":"83","author":"Singh","year":"2022","journal-title":"Toxicol. Vitr."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Yordanova, L., Simeonova, L., Metodiev, M., Bachvarova-Nedelcheva, A., Kostova, Y., Atanasova-Vladimirova, S., Nenova, E., Ivanova, I., Yocheva, L., and Pavlova, E. (2025). Antimicrobial, oxidant, cytotoxic, and eco-safety properties of sol\u2013gel-prepared silica\u2013copper nanocomposite materials. Pharmaceuticals, 18.","DOI":"10.3390\/ph18070976"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"100542","DOI":"10.1016\/j.impact.2025.100542","article-title":"A catalytic perspective to nanomaterials reactivity-based toxicity; implications for single- and multiple-component nanomaterials (nanocomposites)","volume":"37","author":"Portela","year":"2025","journal-title":"NanoImpact"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"6789","DOI":"10.1007\/s11696-022-02360-4","article-title":"Prooxidant, antioxidant and biological activity of nanocomposites of reduced graphene oxide, silver, copper and their combinations","volume":"76","author":"Pavlova","year":"2022","journal-title":"Chem. Pap."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Pavlova, E.L., Nenova, E.P., Yocheva, L.D., Ivanova, I.A., and Georgiev, P.A. (2024). Antimicrobial and oxidative activities of different levels of silver-exchanged zeolites X and ZSM-5 and their ecotoxicity. Pharmaceuticals, 17.","DOI":"10.3390\/ph17121586"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Dastagir, G., Shah, S.T., Pavlova, E., Jamal, A., Seleiman, M.F., and \u010cern\u00fd, J. (2024). Green synthesis, characterization and pharmaceutical applications of biocompatible zinc oxide nanoparticles using Heliotropium rariflorum stocks. Pharmaceuticals, 17.","DOI":"10.3390\/ph17111457"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Mart\u00ednez, L., Keller, A.A., Westerhoff, P., Holden, P.A., Hendren, C.O., Loureiro, S., and Fernandes, T.F. (2023). Daphnia as a model organism to probe biological responses to nanomaterials\u2014From individual to population effects via adverse outcome pathways. Front. Toxicol., 5.","DOI":"10.3389\/ftox.2023.1178482"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2897","DOI":"10.1039\/C9EN00280D","article-title":"Toxicity, bioaccumulation and biotransformation of Cu oxide nanoparticles in Daphnia magna","volume":"6","author":"Neto","year":"2019","journal-title":"Environ. Sci. Nano"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1007\/s11270-016-3206-3","article-title":"Toxicity of Cu and Cr nanoparticles to Daphnia magna","volume":"228","author":"Lu","year":"2017","journal-title":"Water Air Soil Pollut."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"6550","DOI":"10.7498\/aps.55.6550","article-title":"Diffusion and interface reaction of Cu and Si in Cu\/SiO2\/Si (111) systems","volume":"55","author":"Cao","year":"2006","journal-title":"Acta Phys. Sin."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"425","DOI":"10.3762\/bjnano.8.45","article-title":"Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature","volume":"8","author":"Ghosh","year":"2017","journal-title":"Beilstein J. Nanotechnol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1016\/j.apcatb.2017.06.013","article-title":"Copper-containing zeolites for selective catalytic reduction of NOx with NH3","volume":"217","author":"Zhao","year":"2017","journal-title":"Appl. Catal. B"},{"key":"ref_24","first-page":"2997","article-title":"Synthesis and characterization of copper nanoparticles embedded in silica matrix","volume":"258","author":"ElShamy","year":"2012","journal-title":"Appl. Surf. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1007\/s10971-023-06112-y","article-title":"Transition metal-modification of carrageenan-silica hybrids by a sol\u2013gel method","volume":"107","author":"Soares","year":"2023","journal-title":"J. Sol-Gel Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"27746","DOI":"10.1039\/D2RA05107A","article-title":"A Review on the characterization of metal active sites over Cu-based and Fe-based zeolites for NH3-SCR","volume":"12","author":"Chen","year":"2022","journal-title":"RSC Adv."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1016\/j.aquaculture.2007.11.006","article-title":"Dietary copper requirements of juvenile grouper Epinephelus malabaricus","volume":"274","author":"Lin","year":"2008","journal-title":"Aquaculture"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Wang, T., Chen, X., Long, X., Liu, Z., and Yan, S. (2016). Copper nanoparticles and copper sulphate induced cytotoxicity in hepatocyte primary cultures of epinephelus coioides. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0149484"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Chen, S.Y., Liu, S.T., Lin, W.R., Lin, C.K., and Huang, S.M. (2019). The mechanisms underlying the cytotoxic effects of copper via differentiated embryonic chondrocyte gene 1. Int. J. Mol. Sci., 20.","DOI":"10.3390\/ijms20205225"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1039\/C6CC08100B","article-title":"A Cu (II) complex targeting the translocator protein: In vitro and in vivo antitumor potential and mechanistic insights","volume":"53","author":"Montagner","year":"2017","journal-title":"Chem. Commun."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"602","DOI":"10.59957\/jctm.v58i3.91","article-title":"Cytotoxicity of copper doped SiO2-hydroxypropyl cellulose composites on cancer and non-cancerous cells","volume":"58","author":"Foteva","year":"2023","journal-title":"J. Chem. Technol. Metall."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1080\/02772248.2016.1249368","article-title":"Acute toxicity of copper oxide nanoparticles to Daphnia magna under different test conditions","volume":"99","author":"Thit","year":"2017","journal-title":"Toxicol. Environ. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Cojocaru, P., Pastia, M.C., Biali, G., and Cojocaru, C. (2025). Heavy metal toxicity on Daphnia magna. Environments, 12.","DOI":"10.3390\/environments12030070"},{"key":"ref_34","first-page":"245","article-title":"Toxicity of copper nanopartical in Daphnia magna","volume":"39","author":"Kien","year":"2017","journal-title":"Acad. J. Biol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1080\/00288330.2019.1598447","article-title":"Comparative toxic effects of copper-based nanoparticles and their microparticles in Daphnia magna by using natural freshwater media","volume":"53","author":"Arratia","year":"2019","journal-title":"N. Zealand J. Mar. Freshw. Res."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Saif, S., Tahir, A., Asim, T., and Chen, Y. (2016). Plant mediated green synthesis of CuO nanoparticles: Comparison of toxicity of engineered and plant mediated CuO nanoparticles towards Daphnia magna. Nanomaterials, 6.","DOI":"10.3390\/nano6110205"},{"key":"ref_37","unstructured":"(2004). Test No. 202: Daphnia sp. Acute Immobilization Test, OECD Publishing."}],"container-title":["Pharmaceuticals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8247\/19\/1\/35\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T14:13:52Z","timestamp":1766499232000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8247\/19\/1\/35"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,23]]},"references-count":37,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["ph19010035"],"URL":"https:\/\/doi.org\/10.3390\/ph19010035","relation":{},"ISSN":["1424-8247"],"issn-type":[{"value":"1424-8247","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,23]]}}}