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229 results on '"Espro, Claudia"'

7. Modified Gold Screen-Printed Electrodes for the Determination of Heavy Metals.

Author

Celesti, Consuelo, Giofrè, Salvatore Vincenzo, Espro, Claudia, Legnani, Laura, Neri, Giovanni, and Iannazzo, Daniela

Subjects
GOLD electrodes, HEAVY metals, METAL detectors, METAL ions, SQUARE waves
Abstract

Screen-printed electrodes (SPEs) are reliable, portable, affordable, and versatile electrochemical platforms for the real-time analytical monitoring of emerging analytes in the environmental, clinical, and agricultural fields. The aim of this study was to evaluate the electrochemical behavior of gold screen-printed electrodes (SPGEs) modified with molecules containing amino (Tr-N) or α-aminophosphonate (Tr-P) groups for the selective and sensitive detection of the toxic metal ions Pb2+ and Hg2+ in aqueous samples. After optimizing the analytical parameters (conditioning potential and time, deposition potential and time, pH and concentration of the supporting electrolyte), anodic square wave stripping voltammetry (SWASV) was used to evaluate and compare the electrochemical performance of bare or modified electrodes for the detection of Hg2+ and Pb2+, either alone or in their mixtures in the concentration range between 1 nM and 10 nM. A significative improvement in the detection ability of Pb2+ ions was recorded for the amino-functionalized gold sensor SPGE-N, while the presence of a phosphonate moiety in SPGE-P led to greater sensitivity towards Hg2+ ions. The developed sensors allow the detection of Pb2+ and Hg2+ with a limit of detection (LOD) of 0.41 nM and 35 pM, respectively, below the legal limits for these heavy metal ions in drinking water or food, while the sensitivity was 5.84 µA nM−1cm−2 and 10 µA nM−1cm−2, respectively, for Pb2+ and Hg2+. The reported results are promising for the development of advanced devices for the in situ and cost-effective monitoring of heavy metals, even in trace amounts, in water resources. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Controllable deposition of dispersed Pd nanoparticles on ZnO for Suzuki–Miyaura cross-coupling reactions.

Author

Bressi, Viviana, Len, Thomas, Polidoro, Daniele, Esposito, Roberto, Mazur, Michal, Selva, Maurizio, Espro, Claudia, and Luque, Rafael

Subjects
SUZUKI reaction, METAL nanoparticles, NANOPARTICLES, PALLADIUM, METALS, ZINC oxide
Abstract

Palladium nanoparticles find extensive applications in catalysis in both homogeneously and heterogeneously catalyzed processes. Supporting metal nanoparticles enhances their stability as compared to their unsupported counterparts. The role of catalytic support is increasingly recognized as crucial in determining the behaviour of these materials. However, controlling the deposition and anchoring of palladium nanoparticles remains a significant challenge. This contribution discusses the preparation of straight lines of palladium particles on zinc oxide by wet impregnation. This phenomenon is attributed to the highly stepped morphology of the employed ZnO that created steric anchoring sites to stabilize the metal particles. Palladium-based catalysts were evaluated for the valuable Suzuki–Miyaura cross-coupling reaction. The dispersed Pd/ZnO catalyst achieved a conversion rate of 86% with 100% selectivity, remarkably superior to that of the Pd/Al2O3 and Pd/TiO2 counterparts. [ABSTRACT FROM AUTHOR]

Published
2023
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27. A Sensitive and Selective Non-Enzymatic Dopamine Sensor Based on Nanostructured Co 3 O 4 –Fe 2 O 3 Heterojunctions.

Author

Khan, Madiha, Abid, Khouloud, Ferlazzo, Angelo, Bressi, Viviana, Espro, Claudia, Hussain, Mozaffar, Foti, Antonino, Gucciardi, Pietro Giuseppe, and Neri, Giovanni

Subjects
DOPAMINE receptors, P-N heterojunctions, DOPAMINE, ELECTROCHEMICAL sensors, HETEROJUNCTIONS, CARBON electrodes, METALLIC oxides
Abstract

In the present work, a study was carried out with the aim of enhancing the performance of electrochemical biosensors based on Co3O4:Fe2O3 heterojunctions. Specifically, the redox behavior of screen–printed carbon electrodes (SPCEs) modified with Co3O4:Fe2O3 (0.5 wt%:x wt%) nanocomposites, where x ranged from 0.1 to 0.5 wt%, was examined in detail. The hybrid nanocomposites were synthesized using the sol-gel auto-combustion method. Several characterization methods were performed to investigate the morphology, microstructure, and surface area of the pure Co3O4, pure Fe2O3, and the synthesized Co3O4:Fe2O3 nanocomposites. Using cyclic voltammetry (CV) tests, the electrochemical behavior of the modified electrodes toward the dopamine (DA) molecules was investigated. The modified Co3O4:Fe2O3, (0.5 wt%, x = 0.4 wt%)/SPCE resulted in a sensor with the best electrochemical performance toward DA. A high linear relationship between DA concentrations and the faradic current variation (ipa (μA) = 0.0736 + 0.1031 CDA (μA) and R2 = 0.99) was found in the range of 10–100 μM. The sensitivity value was computed to be 0.604 µA µM−1cm−2 and the limit of detection (LOD) 0.24 µM. Based on the characterization and electrochemical results, it can be suggested that the formation of Co3O4:Fe2O3 heterostructures provides a large specific surface area, an increased number of electroactive sites at the metal oxide interface and a p–n heterojunction, thus ensuring a remarkable enhancement in the electrochemical response towards DA. [ABSTRACT FROM AUTHOR]

Published
2023
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29. Chitosan/POSS Hybrid Hydrogels for Bone Tissue Engineering

Author

Celesti, Consuelo, primary, Iannazzo, Daniela, additional, Espro, Claudia, additional, Visco, Annamaria, additional, Legnani, Laura, additional, Veltri, Lucia, additional, Visalli, Giuseppa, additional, Di Pietro, Angela, additional, Bottino, Paola, additional, and Chiacchio, Maria Assunta, additional

Published
2022
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30. Orange-Peel-Derived Nanobiochar for Targeted Cancer Therapy

Author

Iannazzo, Daniela, primary, Celesti, Consuelo, additional, Espro, Claudia, additional, Ferlazzo, Angelo, additional, Giofrè, Salvatore V., additional, Scuderi, Mario, additional, Scalese, Silvia, additional, Gabriele, Bartolo, additional, Mancuso, Raffaella, additional, Ziccarelli, Ida, additional, Visalli, Giuseppa, additional, and Di Pietro, Angela, additional

Published
2022
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45. Determination of Phenylalanine by a Novel Enzymatic PHD/SPE Biosensor

Author

Ferlazzo, Angelo, Espro, Claudia, Iannazzo, Daniela, and Neri, Giovanni

Abstract

In this article, we report the first example of a novel potentiometric sensor for the real-time monitoring of phenylalanine (Phe). The developed enzymatic biosensor consists of a commercial screen-printed electrode (SPE) platform with the gold working electrode covalently functionalized with the enzyme Phe dehydrogenase (PHD). The PHD/SPE membrane-free biosensor was fabricated by immobilizing the PHD enzyme to the gold electrode using 3-3’-dithiopropionic acid of $N$ -succinimide ester (DSP) as a linker capable of creating a thiol bond with the gold electrode and an amide bond with the amine group present on the PHD enzyme. The ability of the enzyme to catalyze the transformation of Phe to pyruvic acid, NADH, and ammonia, under the conditions used for the enzymatic biosensor, was first assessed by UV-Vis analysis under batch conditions. Under the experimental conditions adopted, the enzymatic reaction was almost completed in 40–60 min. The biosensor was then tested for the Phe monitoring using the open circuit potential (OCP) potentiometric technique, recording the potential of the biosensor as the reaction proceeded over time. The potentiometric response with respect to the Ag/AgCl reference electrode was found to be linear over a relatively wide concentration range (0– $5000 \mu \text{M}$ ). The reported results demonstrated the feasibility of developing a novel membrane-free enzymatic biosensor for Phe monitoring in patients affected with phenylketonuria (PKU).

Published
2023
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