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Copper nanoparticles obtained by laser ablation in liquids as bactericidal agent for dental applications
摘要： The dramatic increase of antibiotic-resistant bacteria is considered one of the greatest threats to human health at global scale. The antibacterial activity of noble metal nanoparticles, could be the solution against bacterial infectious diseases which currently do not respond to conventional treatments. In this work, copper nanoparticles were produced by laser ablation using two different lasers. A nanosecond laser operating at 532nm and a picosecond laser at 1064nm were used to ablate a copper target submerged in water and methyl alcohol. The obtained colloidal solutions consisted of copper oxide nanoparticles in suspension with diameters ranging from few nanometers to 45 nm. The nanoparticles formation process is highly influenced by laser parameters, but the solvent plays a crucial role on their characteristics. Cu oxide nanoparticles obtained in water present chain-like nanostructure, while those obtained in methyl alcohol are spherical with lower presence of oxide. All the obtained nanoparticles are crystalline and noticeably stable. Microbiology confirm their strong activity against Aggregatibacter actinomycetemcomitans. Cytocompatibility with human periodontal ligament stem cells is also confirmed. The biological assays evidence that ions release is not the main parameter responsible for the bactericidal activity of copper nanoparticles. Other factors such as oxidation state, size and crystallographic structure, have a greater influence on the process.
关键词： noble metal nanoparticles,laser ablation,copper nanoparticles,antibacterial effect
更新于2025-09-12 10:27:22
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Effects of shape-controlling cationic and anionic surfactants on the morphology and surface resonance plasmon intensity of silver@copper bimetallic nanoparticles
摘要： Cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were used as a soft template to determine the morphology of silver@copper bimetallic nanoparticles. The subsequent addition of ascorbic acid to the Ag+, Cu2+ and surfactants solutions, leads to the formation of prefect transparent pale yellow color with in 5 min at ca. 409 nm. The visual observations and UV-visible spectra reveal that the color (pale yellow, dark brown, and wine red), surface resonance plasmon (SRP) intensity and shape of the spectra depends on the Ag+/Cu2+ molar ratio, [CTAB], and reaction time. Sub-, post- and dilution micellar effects are accountable to the fast and slow nucleation and growth processes. The morphology and SRP and rate constants for the formation of silver@copper decreases with increasing [CTAB]. The typical optical properties were dominated by the silver metal. The absence of SRP peaks at ca. 425 nm, 590 nm and 800 nm ruled out the possibility to the formation of AgNPs, CuNPs and CuO, respectively. Transmission electron microscopy (TEM) also confirms the formation of silver@copper nanoparticles. The pseudo-first order rate constants, activation energy, enthalpy of activation and entropy of activation were calculated and discussed for the degradation of methyl orange. The mole fraction of XAg = 0.50 and XCu = 0.499 were calculated in silver@copper.
关键词： silver@copper,Nanoparticles,Mole fraction,SDS,CTAB
更新于2025-09-10 09:29:36