Papers by Ligia Maria MORETTO
Chemosensors, Mar 2, 2017
Immunoglobulin Y is a water-soluble protein present in high concentration in hen serum and egg yo... more Immunoglobulin Y is a water-soluble protein present in high concentration in hen serum and egg yolk. IgY has applications in many fields, e.g., from food stuff to the mass production of antibodies. In this work, we have implemented an electrochemical immunosensor for IgY based on templated nanoelectrodes ensembles. IgY is captured by the templating polycarbonate and reacted with anti-IgY labeled with horseradish peroxidase. In the presence of H 2 O 2 and methylene blue as the redox mediator, an electrocatalytic current is generated which scales with IgY concentration in the sample. After optimizing the extracting procedure, the immunosensor was applied for analysis of fresh eggs and food integrators. The data obtained with the biosensor were validated by SDS-PAGE and Western blot measurements.
Nanotechnology, Mar 22, 2011
Ordered arrays of nanoelectrodes for electrochemical use are prepared by electron beam lithograph... more Ordered arrays of nanoelectrodes for electrochemical use are prepared by electron beam lithography (EBL) using polycarbonate as a novel e-beam resist. The nanoelectrodes are fabricated by patterning arrays of holes in a thin film of polycarbonate spin-coated on a gold layer on Si/Si 3 N 4 substrate. Experimental parameters for the successful use of polycarbonate as high resolution EBL resist are optimized. The holes can be filled partially or completely by electrochemical deposition of gold. This enables the preparation of arrays of nanoelectrodes with different recession degree and geometrical characteristics. The polycarbonate is kept on-site and used as the insulator that separates the nanoelectrodes. The obtained nanoelectrode arrays (NEAs) exhibit steady state current controlled by pure radial diffusion in cyclic voltammetry for scan rates up to approximately 50 mV s -1 . Electrochemical results showed satisfactory agreement between experimental voltammograms and suitable theoretical models. Finally, the peculiarities of NEAs versus ensembles of nanoelectrodes, obtained by membrane template synthesis, are critically evaluated.
Lecture notes in electrical engineering, 2023
Applied Organometallic Chemistry
A straightforward synthetic route to a selection of new ferrocenyl complexes bearing different or... more A straightforward synthetic route to a selection of new ferrocenyl complexes bearing different organopalladium fragments is reported. The target complexes were fully characterized by Nuclear Magnetic Resonance, High Resolution Mass Spectrometry, Infrared Spectroscopy, X‐ray Diffraction, and electrochemical techniques. All compounds, with the exception of Pd(0)‐olefin derivatives, showed excellent antitumor activity on ovarian cancer cells and, in the case of Pd (II)‐allyl and Pd (II)‐butadienyl complexes, a lower cytotoxicity towards normal cells.
Ion-exchange voltammetry is an electroanalytical technique which employs solid electrodes modifie... more Ion-exchange voltammetry is an electroanalytical technique which employs solid electrodes modified by a thin film of ion-exchange polymers [1]. The polymeric coating allows the selective ion-exchange preconcentration and voltammetric determination of traces inorganic and organic electroactive ions of interest for environmental, biomedical or pharmaceutical analysis. Usually, the ion-exchange film is deposited by dipor spin-coating procedures, which however suffer for relatively scarce reproducibility, lack of control of the structure and surface properties of the film and require relatively high equilibration time for the preconcentration of the analyte. Recently, in our laboratory we developed original methods for preparing ultrathin films of ionomeric polymers (Nafion, Tosflex, Eastman AQ) by using Langmuir-Schaefer (LS) [2,3] and Langmuir-Blodgett (LB) techniques [4]. Information on morphological characteristics of the ultrathin coatings were obtained by atomic force microscopy a...
Analytical and bioanalytical chemistry, Jan 26, 2015
In general the analysis of archeological glass represents a challenge for a wide variety of objec... more In general the analysis of archeological glass represents a challenge for a wide variety of objects because of the presence of physical and/or chemical damage on the surface of the artifact, also known as weathering or corrosion. To retrieve accurate bulk elemental information by laser ablation-inductively coupled plasma-mass spectrometry (ICP-MS), the original, pristine glass needs to be "reached", thereby penetrating the alteration layer which is often more than 10 μm thick. To study this alteration layer the laser was operated in the drilling mode, either with a low (1 Hz) or a high (10 Hz) pulse repetition rate for a period of 50 s yielding detailed spatial information for ca. 20 elements over a shallow depth (ca. 5 μm) or less-detailed spatial information for 50-60 elements over a greater depth (ca. 50 μm). Quantitative elemental depth profiles (in wt%) were obtained with the so-called sum normalization calibration protocol, based on summation of the elements as their...
Electrochimica Acta, 2014
ABSTRACT Pyrolyzed photoresist carbon electrodes (PPCEs) are fabricated by the photopatterning of... more ABSTRACT Pyrolyzed photoresist carbon electrodes (PPCEs) are fabricated by the photopatterning of a negative tone epoxy-based photoresist, SU-8, through optimized standard UV photolithography. The electrochemical characteristics of PPCEs are investigated in dimethyl sulfoxide (DMSO), observing a wider accessible potential window and a smaller capacitance with respect to glassy carbon electrodes. PPCEs are used to study the cyclic voltammetric behavior of bilirubin (BR) in DMSO. Detailed information is obtained on the multiple steps involved both in the electrochemical oxidation and reduction of BR. Interesting points concerning the electrochemical oxidation of BR to biliverdin are clarified, identifying the formation of an intermediate whose fate depends on the time scale of the electrochemical experiment. PPCEs are also used to electrogenerate the superoxide anion O2 �� in DMSO for studying possible reactions between BR and O2 ��. The results obtained demonstrate that BR is an efficient superoxide scavenger and that a concentration 2 mM of BR is high enough to consume all the O2 �� generated by oxygen reduction at the PPCE/DMSO interface.
Lecture Notes in Electrical Engineering, 2013
International Journal of Environmental Analytical Chemistry, 2010
Bioelectrochemistry and Bioenergetics, 1995
The dependence of the activity of iron-containing superoxide dismutase from Escherichia coli on p... more The dependence of the activity of iron-containing superoxide dismutase from Escherichia coli on pH and ionic strength was investigated extensively in the ranges 7.7-11.0 and 0.02-0.25 M respectively. The results show that the enzymatic activity diminishes with both increasing pH and increasing ionic strength, reaching a minimum value at about pH 11. The activity decrease with increasing pH was ascribed to a gradual titration, by OH-ion, of the acid group Fe3+-H20. This gives rise to a deprotonated enzymatic form with a residual activity which is about 10% that of the protonated form. The dependence of the activity on ionic strength was interpreted as a Debye-HUckel effect.
Bioelectrochemistry, Aug 1, 2020
The immobilization of biomolecules at screen printed electrodes for biosensing applications is st... more The immobilization of biomolecules at screen printed electrodes for biosensing applications is still an open challenge. To enrich the toolbox of bioelectrochemists, graphite screen printed electrodes (G-SPE) were modified with an electropolymerized film of pyrrole-2-carboxilic acid (Py-2-COOH), a pyrrole derivative rich in carboxylic acid functional groups. These functionalities are suitable for the covalent immobilization of biomolecular recognition layers. The electropolymerization was first optimized to obtain stable and conductive polymeric films, comparing two different electrolytes: sodium dodecyl sulphate (SDS) and sodium perchlorate. The G-SPE modified with Py-2-COOH in 0.1 M SDS solution showed the required properties and were further tested. A proof-of-concept study for the development of an impedimetric sensor for perfluorooctanoic acid (PFOA) was carried out using the delipidated human serum albumin (hSA) as bioreceptor. The data interpretation was supported by size exclusion chromatography and small-angle X-ray scattering (SEC-SAXS) analysis of the bioreceptor-target complex and the preliminary results suggest the possibility to further develop this biosensing strategy for toxicological and analytical studies.
Journal of Archaeological Science: Reports
Powder Technology, Feb 1, 2019
Despite the importance of carbonation in many processes, still the reaction needs investigation. ... more Despite the importance of carbonation in many processes, still the reaction needs investigation. The reaction is essential for the effectiveness of consolidants, based on CaCO 3 forming products, used in stone conservation. Research on carbonation of two calcium alkoxides products, developed during the Nanomatch project, is presented in this paper and the results discussed and compared with those reported with the most used nanolimes. Calcium tetrahydrofurfuryloxide (Ca(OTHF) 2), dissolved in four different solvents, and calcium ethoxide (Ca(OEt) 2), diluted in ethanol, were applied on glass slides and their carbonation kinetics investigated together with their coatings after being kept in uncontrolled and controlled RH conditions (50% and 90%). This allowed to understand the evolution and the phases formed along the process. Carbonation follows the two pathways already reported for alkoxides; it is a quick process and eventually leads to the formation of the most stable crystalline phase (calcite), with high humidity favouring this final step. Alkoxides resulted thus to
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Papers by Ligia Maria MORETTO