Electrodeposition of Au Nanoparticles on 2D Layered Materials and Their Applications in Electrocatalysis of Nitrite Oana Elena Carp, Mirela-Fernanda Zaltariov, Mariana Pinteala, Adina Arvinte Chemosensors, 2025 This study presents a comparative analysis of gold nanoparticles electrodeposited on different two-dimensional materials used as electrode substrates, graphene (Gr) and MoS2, or co-deposited with the metallic material MoS2. The morphological and electrochemical data demonstrate the efficiency of the electrodeposition process and the preferability of gold nanoparticles for certain attachment sites depending on the nature of the material used as a substrate and the deposition method used. The electrocatalytic activity of the gold nanoparticles obtained in these configurations was evaluated via the oxidation of nitrite ions (NO2−), using both qualitative and quantitative approaches, by cyclic voltammetry and amperometry techniques. The electrocatalytic activity of gold nanoparticles co-deposited with MoS2 is superior compared to that of gold nanoparticles deposited either on bare gold electrodes or on 2D materials (graphene and MoS2), showing good performance with a specific sensitivity of 1.043 μA µM−1 cm−2 on the linear range of 0.5–600 µM nitrite, with a limit of detection of 0.16 µM and good anti-interference ability.
Electrochemical Sensor for Tryptophan Determination Based on Trimetallic-CuZnCo-Nanoparticle-Modified Electrodes Adina Arvinte, Ana-Lacramioara Lungoci, Adina Coroaba, Mariana Pinteala Molecules, 2024 The superior properties of electrodeposited trimetallic CuZnCo nanoparticles, arising from the synergistic effect of combining the unique features of metallic components, were confirmed using voltametric measurements. The surface morphology and structure of the as-prepared electrocatalysts were determined using scanning electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy techniques. Here, the trimetallic CuZnCo nanoparticles were synthesized as a powerful redox probe and highly efficient signal amplifier for the electrochemical oxidation of tryptophan. Differential pulse voltammetry studies showed a linear relationship with a tryptophan concentration of 5–230 μM, and the low detection limit was identified at 1.1 μM with a sensitivity of 0.1831 μA μM−1 cm−2.
Innovative Non-Enzymatic Electrochemical Quantification of Cholesterol Oana Elena Carp, Mariana Pinteala, Adina Arvinte Sensors, 2022 The use of the Liebermann–Burchard reaction in this study has been explored in the development of a simple, reliable, and robust quantitative electrochemical method to assay cholesterol, and hence provide a good alternative to colorimetric methods. The optimization of batch mode operation for electrochemical oxidation of cholesterol in the Liebermann–Burchard reagents included the applied potential and acidic volume. Tested using chronoamperometry, the developed method showed a high sensitivity (14.959 μA mM−1) and low detection limit (19.78 nM) over a 0.025–3 mM concentration range, with remarkable linearity (R2 = 0.999), proving an analytical performance either higher or comparable to most of the cholesterol sensors discussed in literature. The influence of possible interfering bioactive agents, namely, glucose, uric acid, ascorbic acid, KCl and NaCl, has been evaluated with no or negligible effects on the measurement of cholesterol. Our study was directed at finding a new approach to chemical processing arising from the use of external potential as an additional level of control for chemical reactions and the transfer of electrons between surfaces and molecules. Finally, the optimized method was successfully applied for the determination of cholesterol content in real blood samples.
Effect of TAT-DOX-PEG irradiated gold nanoparticles conjugates on human osteosarcoma cells Raoul V. Lupusoru, Daniela A. Pricop, Cristina M. Uritu, Adina Arvinte, Adina Coroaba, et al. Scientific Reports, 2020 The paper aims to investigate the cytotoxic effect on tumor cells of irradiated AuNPs in green light and subsequently functionalized with HS-PEG-NH2. The toxicity level of gold conjugates after their functionalization with DOX and TAT peptide was also evaluated. The AuNPs were prepared using the modified Turkevich method and exposed to visible light at a wavelength of 520 nm prior their PEGylation. The optical properties were analyzed by UV-vis spectroscopy, the surface modification was investigated using FTIR and XPS spectroscopies and their sizes and morphologies were evaluated by TEM and DLS techniques. DOX and TAT peptide were linked to the surface of PEGylated AuNPs by reacting their amino groups with glycidyloxypropyl of PEGylated DOX or TAT conjugates under mild conditions at room temperature and in the presence of ethanol as catalyst. The conjugates containing DOX or DOX and TAT have been characterized by fluorescence and FTIR techniques. The changes of electrochemical features were observed using cyclic voltammetry, suggesting a better stability of irradiated nanoparticles. By mass spectrometry it was confirmed that the compounds of interest were obtained. The cell viability test showed that irradiated and non-irradiated nanoparticles coated with PEG are not toxic in normal cells. Tumor cell viability analysis showed that the PEGylated nanoparticles modified with DOX and TAT peptide were more effective than pristine DOX, indicating cytotoxicity up to 10% higher than non-irradiated ones.