Search Results (191)

Background: Tyrosinase is a copper-dependent oxyreductase capable of catalyzing the oxidation of mono- and diphenols. Its activity is crucial in the biosynthetic pathway of melanin, the pigment responsible for the pigmentation of mammalian skin and fur, and protecting their skin from harmful UV radiation. Overproduction of this pigment leads to numerous pathological conditions, including the most severe form of skin cancer—malignant melanoma. Furthermore, tyrosinase produced in plant tissues leads to the browning of damaged vegetables and fruits. Therefore, the search for compounds that effectively and efficiently control tyrosinase activity is desirable for both pharmaceutical and food applications. Methods: A group of six boronate derivatives of thiosemicarbazones was synthesized, and their inhibitory properties against tyrosinase were determined. Furthermore, their ability to inhibit melanogenesis and proliferation in SK-MEL-3 and Hs294T cells was investigated. Docking simulations were performed to determine the nature of the inhibitor–protein interactions. Results: The tested inhibitors exhibited half-maximal inhibitory concentrations (IC₅₀) in the micromolar range. The best inhibitor, compound 6, had an IC₅₀ of 1.4 µM. The tested compounds exhibited poor selectivity for cell lines capable of high and low tyrosinase overexpression, with inhibitor 4 proving to be the most selective compound among those tested. Molecular modeling results indicate that the compounds with the highest activity against tyrosinase interact with the active cavity and the copper ions present within it via a boron moiety substituted on the aromatic ring of the thiosemicarbazones. Cell-based experiments indicated limited antiproliferative effects up to 100 µM across the tested lines. The compounds demonstrated weak antiproliferative effects in SK-MEL-3 and Hs-294T up to 100 µM. Conclusions: Our results show that the introduction of a boronic acid moiety is an alternative to carboxylic acid derivatives, improving the inhibitory activity of boron analogs (by fourfold) against fungal tyrosinase. Full article

Electrochemical CO₂ reduction reaction (CO₂RR) is a key technology for achieving carbon neutrality and efficient utilization of renewable energy, capable of converting CO₂ into high-value-added carbon-based fuels and chemicals. Copper (Cu)-based catalysts have attracted significant attention due to their unique performance in generating multi-carbon (C₂₊) products such as ethylene and ethanol; however, there are still many controversies regarding their complex reaction mechanisms, active sites, and the dynamic evolution of intermediates. In situ Raman spectroscopy, with its high surface sensitivity, applicability in aqueous environments, and precise detection of molecular vibration modes, has become a powerful tool for studying the structural evolution of Cu catalysts and key reaction intermediates during CO₂RR. This article reviews the principles of electrochemical in situ Raman spectroscopy and its latest developments in the study of CO₂RR on Cu-based catalysts, focusing on its applications in monitoring the dynamic structural changes of the catalyst surface (such as Cu⁺, Cu⁰, and Cu²⁺ oxide species) and identifying key reaction intermediates (such as *CO, *OCCO(*O=C-C=O), *COOH, etc.). Numerous studies have shown that Cu-based oxide precursors undergo rapid reduction and surface reconstruction under CO₂RR conditions, resulting in metallic Cu nanoclusters with unique crystal facets and particle size distributions. These oxide-derived active sites are considered crucial for achieving high selectivity toward C₂₊ products. Time-resolved Raman spectroscopy and surface-enhanced Raman scattering (SERS) techniques have further revealed the dynamic characteristics of local pH changes at the electrode/electrolyte interface and the adsorption behavior of intermediates, providing molecular-level insights into the mechanisms of selectivity control in CO₂RR. However, technical challenges such as weak signal intensity, laser-induced damage, and background fluorescence interference, and opportunities such as coupling high-precision confocal Raman technology with in situ X-ray absorption spectroscopy or synchrotron radiation Fourier transform infrared spectroscopy in researching the mechanisms of CO₂RR are also put forward. Full article

Cytisine, a naturally occurring alkaloid and partial agonist of nicotinic acetylcholine receptors (nAChRs), has long been used as a smoking cessation aid and serves as the pharmacophore for varenicline. Recent research has expanded its therapeutic scope to neurodegenerative and neurological disorders, motivating the development of new cytisine derivatives. Among these, N-propargylcytisine combines the biological activity of the parent compound with the synthetic versatility of the terminal alkyne group. Herein, we report the synthesis and characterization of N-propargylcytisine, and its symmetrical dimer linked through 1,3-diyne moiety obtained via a copper-mediated Glaser–Hay oxidative coupling. The products were analyzed by NMR, FT-IR, and mass spectrometry, confirming the introduction of the propargyl moiety and the formation of the diyne bridge. Solvatochromic study of both compounds were performed using UV-VIS absorption spectroscopy in solvents of varying polarity, including protic solvents capable of hydrogen bonding. The 1,3-diyne motif, commonly found in bioactive natural products, endows the resulting dimer with potential for further derivatization and biological evaluation. This study demonstrates the utility of the Glaser–Hay reaction in the functionalization of alkaloid scaffolds and highlights the prospects of N-propargylcytisine derivatives in drug discovery targeting the central nervous system. Full article

The Permian Kupferschiefer shale, a key stratigraphic unit within the Zechstein sequence of the Fore-Sudetic Monocline, represents both a metal-rich lithofacies and a potential source rock for hydrocarbon generation. This study presents a comprehensive geochemical characterization of selected Kupferschiefer samples obtained from the Legnica–Głogów Copper District (LGOM) and exploratory boreholes. Analytical methods included Rock-Eval pyrolysis, Py-GC/FID, elemental analysis, TG-FTIR, biomarker profiling, and stable carbon isotope measurements. Results indicate that the shales contain significant amounts of Type II and mixed Type II/III kerogen, derived primarily from marine organic matter with minor terrestrial input. The organic matter maturity, expressed by T_max, places most samples within the oil window. Rock-Eval S2 values exceed 60 mg HC/g rock in some samples, confirming excellent generative potential. Py-GC/FID data further support high hydrocarbon yields, particularly in samples from the CG-4 borehole and LGOM mines. The thermal decomposition of kerogen reveals multiple degradation phases, with evolved gas analysis identifying sulfur-containing compounds and hydrocarbons indicative of sapropelic origin. Isotopic compositions of bitumen and kerogen suggest syngenetic relationships and marine depositional settings, with samples from a North Poland borehole showing isotopic enrichment consistent with post-depositional oxidation. Kinetic parameters calculated using the Kissinger–Akahira–Sunose method demonstrate variable activation energies (107–341 kJ/mol), correlating with differences in organic matter composition and mineral matrix. The observed variability in geochemical properties highlights both regional and facies-dependent influences on the shale’s generative capacity. The study concludes that the Kupferschiefer in southwestern and northern Poland exhibits substantial hydrocarbon generation potential. This potential has been previously underestimated due to the unit’s thinness, but localized zones with high TOC, favorable kerogen type, and low activation energy could be viable exploration targets for natural gas. Full article

This work describes the synthesis and characterization of novel organometallic polymeric frameworks derived from lactone-based poly(benzofuran-co-arylacetic acid) (PBAAA) ligands complexed with 3d transition metal salts (Co²⁺, Cu²⁺, Zn²⁺). Two distinct synthetic approaches were investigated: conventional solution-based methods and mechanochemical ball milling. A comprehensive spectroscopic evaluation was performed utilizing FTIR, XRD, UV-Vis, and XPS techniques to detail the structural characteristics of the synthesized materials. The thermal assessments were conducted using TGA and thermal conductivity, demonstrating that the chosen synthesis method has a significant impact on the crystallinity, coordination environment, and thermal transport characteristics of the resultant complexes. Remarkably, using the mechanosynthesis, the resulting organometallic polymer materials exhibited enhanced chain ordering and improved thermal conductivity, with a value of 0.32 W/mK, almost double that of the starting polymer. A correlation was identified among thermal conductivity, metal ionic radius, coordination number, and the synthesis method utilized. XPS analysis revealed the presence of multiple oxidation states and varied electronic environments, particularly in copper complexes. These had a direct effect on how they behaved when heated. These results show that mechanochemical synthesis is a useful and long-lasting method to make complex organometallic polymers with thermal properties that can be changed. Full article

In this work, bare copper oxide-based catalysts were synthesized and evaluated for their dual (photo)catalytic activity in two model reactions: hydrogen generation via formic acid decomposition (FAD) and the photocatalytic hydroxylation of benzene to phenol. Catalysts were prepared from copper nitrate and copper acetate precursors and calcined for either 10 min or 2 h. Their structural and surface properties were characterized by wide-angle X-ray diffraction (WAXD), Raman spectroscopy, and BET surface area analysis. FAD was conducted under mild thermal conditions and monitored via ¹H NMR spectroscopy. At the same time, benzene hydroxylation was performed under UV irradiation and analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC). All synthesized catalysts outperformed commercial CuO in the selective oxidation of benzene. The nitrate-derived sample calcined for 10 min (NCuO 10 min) achieved the best performance, with a phenol yield of ~10% and a selectivity of up to 19%, attributed to improved surface properties and the presence of Cu(I) domains, as indicated by Raman spectroscopy. For FAD, complete conversion of formic acid was achieved at low temperatures, with selective H₂ and CO₂ evolution and complete suppression of CO, even under short reaction times and low catalyst loadings. These results demonstrate the potential of nitrate-derived CuO catalysts as versatile, dual-function materials for sustainable applications in selective aromatic oxidation and low-temperature hydrogen generation, without the need for noble metals or harsh conditions. Full article

Esophageal squamous cell carcinoma (ESCC) accounts for the majority of esophageal cancers worldwide, with a poor prognosis and increasing resistance to conventional treatments. Faced with these limitations, nanoparticles (NPs) are attracting growing interest as innovative therapeutic agents capable of improving specificity and efficacy and reducing systemic toxicity. This study critically examines the pharmacological effects, mechanisms of action, and toxicity profiles of different metallic or organic nanoparticles tested on ESCC cell lines. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines were followed by a meticulous literature search of Google Scholar, Web of Science, PubMed/Medline, and Scopus databases to achieve this goal. The results show that the anti-tumor properties vary according to the type of nanoparticle (copper(II) oxide (CuO), silver (Ag), gold (Au), nickel(II) oxide (NiO), nano-curcumin, etc.), the synthesis method (chemical vs. green), and the biological activity assessment method (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Bromodeoxyuridine (BrdU), Cell Counting Kit-8 (CCK8) assays, etc.). NPs derived from green synthesis, such as those based on Moringa oleifera, Photinia glabra, or pomegranate bark, exhibit moderate cytotoxic activity (50% inhibitory concentration (IC₅₀) between 92 and 500 µg/mL) but show good tolerance on normal cells. In contrast, chemically synthesized NPs, such as Cu(II) complexes with 1,3,5-benzenetricarboxylic acid (H₃btc) or 1,2,4-triazole (Htrz), show lower IC₅₀ (34–86 µM), indicating more marked cytotoxicity towards cancer cells, although data on their toxicity are sometimes lacking. In addition, multifunctional nanoparticles, such as gold-based nano-conjugates targeting Cluster of Differentiation 271 (CD271) or systems combined with doxorubicin, show remarkable activity with IC₅₀ below 3 µM and enhanced tumor selectivity, positioning them among the most promising candidates for future clinical application against ESCC. The most frequently observed mechanisms of action include induction of apoptosis (↑caspases, ↑p53, ↓Bcl-2), oxidative stress, and inhibition of proliferation. In conclusion, this work identifies several promising nanoparticles (silver nanoparticles derived from Photinia glabra (PG), gold-based nano-immunoconjugates targeting CD271, and silver–doxorubicin complexes) for future pharmaceutical exploitation against ESCC. However, major limitations remain, such as the lack of methodological standardization, insufficient in vivo and clinical studies, and poor industrial transposability. Future prospects include the development of multifunctional nanocomposites, the integration of biomarkers for personalized targeting, and long-term toxicological assessment. Full article

Detecting surface mineral indicators with high spatial precision remains a significant challenge in mineral exploration, particularly in remote or geologically complex regions such as Eastern Kazakhstan. This study addresses this challenge by integrating high-resolution multispectral imagery from Unmanned Aerial Vehicles (UAVs) to map iron oxide distributions, key indicators of ore mineralization such as copper porphyry at the Kyzylkiya mining site in Eastern Kazakhstan. The novelty of this study is the development of a statistical fuzzy logic model that integrates UAV-derived spectral indices, including the Normalized Difference Vegetation Index (NDVI) and targeted band ratios, to generate probabilistic maps of iron oxide presence at a fine spatial resolution of 5.29 cm. This approach enhances prediction accuracy by incorporating uncertainty and variability in spectral responses. The model’s output was validated through a multi-stage process involving independent multispectral datasets and ground-truth sampling, achieving an overall accuracy of 80%. The results reveal concentrated iron oxide anomalies in the northeast and northwest of the study area, underscoring the method’s effectiveness. This integrated UAV-fuzzy logic framework demonstrates a scalable and cost-effective solution for early-stage mineral exploration and can be adapted to similar geological settings globally. Full article

The treatment of contaminants from road infrastructure poses significant challenges due to their variable composition and the high concentrations of chloride ions, heavy metals, and oil-derived substances. Traditional methods for protecting groundwater environments are often insufficient. A promising alternative is permeable reactive barrier (PRB) technology, which utilizes recycled materials and construction waste as reactive components within the treatment zone of the ground. This paper delves into the potential of employing a composite (MIX) consisting of modified construction aggregate (as recycled material) and activated carbon (example of reactive material) to address environmental contamination from a mixture of heavy metals and chloride. The research involved chemical modifications of the road aggregate, activated carbon, and their composite, followed by laboratory tests in glass reactors and non-flow batch tests to evaluate the kinetics and chemical equilibrium of the reactions. The adsorption process was stable and conformed to the pseudo-second-order kinetics and Langmuir, Toth, and Redlich–Peterson isotherm models. Studies using MIX from a heavy metal model solution showed that monolayer adsorption was a key mechanism for removing heavy metals, with strong fits to the Langmuir (R² > 0.80) and Freundlich models, and optimal efficiencies for Cd and Ni (R² > 0.90). The best fit, at Cd, Cu, Ni = 0.96, however, was with the Redlich–Peterson isotherm, indicating a mix of physical and chemical adsorption on heterogeneous surfaces. The Toth model was significant for all analytes, fitting Cl and Cd well and Pb and Zn moderately. The modifications made to the composite significantly enhanced its effectiveness in removing the contaminant mixture. The test results demonstrated an average reduction of chloride by 85%, along with substantial removals of heavy metals: lead (Pb) by 90%, cadmium (Cd) by 86%, nickel (Ni) by 85%, copper (Cu) by 81%, and zinc (Zn) by 79%. Further research should focus on the removal of other contaminants and the optimization of magnesium oxide (MgO) dosage. Full article

Copper nanoparticles (CuNPs) are increasingly used in agriculture either alone or in combination with pesticides. Recognizing the potential hazards of CuNPs in soil environments, our study evaluated their effects on the metabolic activity of Nitrobacter winogradskyi ATCC 2539, a chemolithoautotrophic bacterium crucial for the nitrification process, which involves the oxidation of nitrite to nitrate in soil ecosystems. This study evaluated the effects of concentration ranges of CuNPs (2.5 to 162.7 mg L⁻¹), CuONPs (3.2 to 203.6 mg L⁻¹), and various pesticides (iprodione, carbendazim, and 2,4-D) and their derivatives (3,5-dichloroaniline, catechol, and 2,4-dichlorophenol) at concentrations ranging from 0.04 to 2.56 mM. CuSO₄ was also used as a control for comparative purposes. Our findings indicated that the CuNPs significantly inhibited the metabolic activity of N. winogradskyi, resulting in a reduction of up to 95% at concentrations of ≥2.5 mg L⁻¹. The CuONPs were less toxic, while the pesticides and their derivatives generally showed lower toxicity. Notably, combinations of CuNPs with pesticides or their derivatives maintained high toxicity levels comparable to those of the CuNPs alone. According to the Loewe additivity model, these effects were largely additive and primarily associated with CuNPs or CuONPs. Protein profiling using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry (MS) revealed that carbendazim induced noticeable changes in protein profiles. These findings underscore the detrimental impacts of CuNPs and CuONPs on the metabolic activity of N. winogradskyi, posing a considerable risk to the health of agricultural soils. Overall, this research provides crucial insights into the risks associated with using CuNPs in agriculture, particularly regarding their potential threat to nitrifying microorganisms in soils. Full article

The growing prevalence of bacterial infections and the alarming rise of antimicrobial resistance (AMR) have driven the need for innovative antimicrobial coatings for medical implants and biomaterials. However, implant surface properties, such as roughness, chemistry, and reactivity, critically influence biological interactions and must be engineered to ensure biocompatibility, corrosion resistance, and sustained antibacterial activity. This review evaluates three principal categories of antimicrobial agents utilized in surface functionalization: metal/metaloxide nanoparticles, antibiotics, and phytochemical compounds. Metal/metaloxide-based coatings, especially those incorporating silver (Ag), zinc oxide (ZnO), and copper oxide (CuO), offer broad-spectrum antimicrobial efficacy through mechanisms such as reactive oxygen species (ROS) generation and bacterial membrane disruption, with a reduced risk of resistance development. Antibiotic-based coatings enable localized drug delivery but often face limitations related to burst release, cytotoxicity, and diminishing effectiveness against multidrug-resistant (MDR) strains. In contrast, phytochemical-derived coatings—using bioactive plant compounds such as curcumin, eugenol, and quercetin—present a promising, biocompatible, and sustainable alternative. These agents not only exhibit antimicrobial properties but also provide anti-inflammatory, antioxidant, and osteogenic benefits, making them multifunctional tools for implant surface modification. The integration of these antimicrobial strategies aims to reduce bacterial adhesion, inhibit biofilm formation, and enhance tissue regeneration. By leveraging the synergistic effects of metal/metaloxide nanoparticles, antibiotics, and phytochemicals, next-generation implant coatings hold the potential to significantly improve infection control and clinical outcomes in implant-based therapies. Full article

Background: The present work is devoted to the biological effects of sol–gel-derived silica (Si)–copper (Cu) nanomaterials. Methods and Results: Tetraethyl orthosilane (TEOS) was used as a silica precursor; copper was introduced as a solution in ethanol with Cu(OH)₂. The obtained samples were denoted as Si/Cu (gel) and Si/Cu/500 (500 °C heat-treated). Their phase formation and morphology were studied by XRD and SEM. The antibacterial activity was tested by two Gram-positive bacteria, three Gram-negative bacteria, and two types of eukaryotic species. Most bacteria were more sensitive to Si/Cu/500 materials than to Si/Cu (gel). The yeasts were more sensitive to Si/Cu (gel). The new nanomaterials were tested for oxidant activity at pH 7.4 (physiological) and pH 8.5 (optimal) in three model systems by the chemiluminescent method. They significantly inhibited the generation of free radicals and ROS. This result underlines their potential as regulators of the free radical processes in living systems. The epithelial tumor cell lines appeared more sensitive than the non-transformed fibroblasts, likely due to their metabolic activity and proliferation rates, leading to greater accumulation of the substances. Using Daphnia magna, the ecotoxicity study showed that the LC₅₀ was reached at 1 mg/L of Si/Cu/500. Si/Cu (gel) was more toxic. Conclusions: Our results reveal the potential of these nanohybrids to be applied in living, eukaryotic systems. The cytotoxicity evaluation showed higher tolerance of normal, non-transformed cells, in concurrence with the oxidation tests. Full article

Aluminum (Al) is one of the most abundant metals on Earth and is well known as an environmental neurotoxic agent in the pathogenesis of Alzheimer’s disease. Aluminum toxicity is associated with oxidative stress, reduction of antioxidant enzymes, and disruption of the balance of cellular metals, such as iron (Fe), calcium (Ca), and copper (Cu), which causes structural and functional changes in the nervous tissue of the brain or peripheral nervous system. The intake of functional foods, rich in antioxidants, such as quercetin, may be beneficial in combating oxidative stress and neurodegenerative changes in the brain. The aim of this study was to provide deeper insight into the cellular and molecular neuroprotective effects of quercetin in regulating amyloid-beta (Aβ) accumulation, tau pathology, and neuroinflammation in the Al/D-galactose-induced rat model (Al/D-gal) of AD. The results showed that quercetin successfully modulated the impaired homeostatic and neuropathological consequences of aluminum chloride and D-galactose administration over 28 days: it directly protected neurons by regulating the level of oxidative stress and antioxidants, reduced Aβ aggregation by inhibiting the activity of acetylcholinesterase (AChE), increased the survival, growth, and differentiation of nerve cells by maintaining the level of brain-derived neurotrophic factor (BDNF), and regulated microglial immunoreactivity and neuroinflammation by reducing the level of proinflammatory cytokines. The multiple effects confirm that quercetin can be applied as an alternative non-pharmaceutical approach in reducing Al-induced neurotoxicity and maintaining adaptive homeostasis, which consequently affects the functioning of the central nervous system and the whole organism. Full article

Promethazine hydrochloride (PMH) is a first-generation antipsychotic drug created from phenothiazine derivatives that is widely employed to treat psychiatric disorders in human healthcare systems. However, an overdose or long-term intake of PMH can lead to severe health issues in humans. Hence, establishing a sensitive, accurate, and efficient detection approach to detect PMH in human samples is imperative. In this study, we designed orthorhombic copper molybdate microspheres decorated on reduced graphene oxide (Cu₃Mo₂O₉/RGO) composite via the effective one-pot hydrothermal method. The structural and morphological features of the designed hybrid were studied using various spectroscopic methods. Subsequently, the electrochemical activity of the composite-modified screen-printed carbon electrode (Cu₃Mo₂O₉/RGO/SPCE) was assessed by employing voltammetric methods for PMH sensing. Owing to the uniform composition and structural benefits, the combination of Cu₃Mo₂O₉ and RGO has not only improved electrochemical properties but also enhanced the electron transport between PMH and Cu₃Mo₂O₉/RGO. As a result, the Cu₃Mo₂O₉/RGO/SPCE exhibited a broad linear range of 0.4–420.8 µM with a low limit of detection (LoD) of 0.015 µM, highlighting excellent electrocatalytic performance to PMH. It also demonstrated good cyclic stability, reproducibility, and selectivity in the presence of chlorpromazine and biological and metal compounds. Furthermore, the Cu₃Mo₂O₉/RGO/SPCE sensor displayed satisfactory recoveries for real-time monitoring of PMH in human urine and serum samples. This study delivers a promising electrochemical sensor for the efficient analysis of antipsychotic drug molecules. Full article

Copper-based nanoparticles (as Cu₂O) are a key component in marine antifouling paints and, as coatings degrade, release nanoparticles that can affect a wide range of non-target organisms. This study investigates the impact of Cu₂O nanoparticles on the early development of urchins Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis, and benchmarks their toxicity against similarly sized Cu and CuO nanoparticles and ionic copper. Concentration-dependent toxicity was noted for all forms of copper at concentrations in the 1 to 5000 µg L⁻¹ range. EC₅₀ values after Cu₂O exposure indicated that A. lixula (99 µg L⁻¹) was generally more sensitive than the other two species, with EC₅₀ values of 371 µg L⁻¹ and 606 µg L⁻¹ noted for S. granularis and P. lividus, respectively. The same trend across species was noted for both Cu and CuO, although these nanoparticles generally showed higher EC₅₀ values, indicating lower toxicity compared to Cu₂O. LC₅₀ values qualitatively parallel the corresponding EC₅₀ values, with Cu₂O consistently the most toxic, while Cu was less harmful, and CuO did not reach LC₅₀ at any concentration. Again, greatest lethality was noted in A. lixula. While copper ion release from Cu was much greater than from CuO and Cu₂O, the latter showed similar or greater toxicity to developing embryos compared to Cu. This indicates that copper ions are not the sole driver of toxicity of Cu₂O, but there may also be a contribution derived from Cu₂O redox activity within cells or at membranes that negatively impact oxidative stress defence mechanisms and metabolic pathways. Full article