Electroanalysis of Naringin at Electroactivated Pencil Graphite Electrode for the Assessment of Polyphenolics with Intermediate Antioxidant Power.

A simple and rapid differential pulse voltammetric (DPV) method using a single-use electroactivated pencil graphite electrode (PGE*) is proposed for the rapid screening of the total content of polyphenolics (TCP) with intermediate antioxidant power (AOP) in grapefruit peel and fresh juice. The results were compared and correlated with those provided by the HPLC-DAD-MS method. NG voltammetric behavior at PGE* was studied by cyclic voltammetry and an oxidation mechanism was suggested.

Development of a label-free aptasensor for monitoring the self-association of lysozyme.

A novel aptamer and surface plasmon resonance (SPR)-based sensor was developed for the label-free detection of lysozyme. The aptasensor is characterised by a detection limit of 1 μg mL(-1) and a linear range of 5-50 μg mL(-1). As an application, we examined the usefulness of the aptasensor for monitoring the early stages of the aggregation of lysozyme.

Disposable biosensor based on platinum nanoparticles-reduced graphene oxide-laccase biocomposite for the determination of total polyphenolic content.

A disposable amperometric biosensor was developed for the detection of total polyphenolic compounds from tea infusions. The biosensor was designed by modifying the surface of a carbon screen-printed electrode with platinum nanoparticles and reduced graphene oxide, followed by the laccase drop-casting and stabilization in neutralised 1% Nafion solution. The obtained biosensor was investigated by scanning electron microscopy and electrochemical techniques.

Validated HPLC-Fl method for the analysis of S-adenosylmethionine and S-adenosylhomocysteine biomarkers in human blood.

The natural methyl donor group, S-adenosylmethionine and its product, S-adenosylhomocysteine play an important role in many biochemical reactions involving transmethylation reactions. These compounds can be used as biomarkers in incipient diagnosis of various pathological disorders therefore the validation of a suitable method to routinely analysis of these compounds is very important. In this paper, a high performance liquid chromatrography method for S-adenosylmethionine and S-adenosylhomocysteine measurement as fluorescent 1,N(6)-ethanoderivatives from biological samples was validated in terms of selectivity, linearity range of the response (R > 0.

Evaluation of Geranium spp., Helleborus spp. and Hyssopus spp. polyphenolic extracts inhibitory activity against urease and α-chymotrypsin.

This study was meant to determine the inhibitory activity of tannins and flavonoid compounds from Geranium robertianum, Helleborus purpurascens and Hyssopus officinale plant polyphenol rich extracts against urease and α-chymotrypsin. The G. robertianum, H.

Methods for the determination of antioxidant capacity in food and raw materials.

A comprehensive description of the most frequently used methods to determine the antioxidant activity in food and raw materials is given. The methods are classified into two categories, depending on the type of the assessment carried out. Several methods for the assessment ofantioxidant efficacy using free radical scavenging such as oxygen radical absorbance capacity assay (ORAC), total radical trapping antioxidant parameter assay (TEAC), ferric reducing antioxidant power assay (FRAP) and 2,2'-diphenyl-11-picrylhydrazyl (DPPH) assay are described.

Biosensors for the determination of phenolic metabolites.

Antioxidants are groups of chemical substances, the most abundant being polyphenols, mainly found in plants, fruits and vegetables. They include flavonoids, flavonoid derivatives, polyphenols, carotenoids and anthocyanins. Currently, the nutritional quality of many foodstuffs is guaranteed by the presence of antioxidant compounds.

Hydrogel-magnetic nanoparticles with immobilized L-asparaginase for biomedical applications.

The association of magnetic nanoparticles, which could be controlled by a magnetic field and have dimensions which facilitate their penetration in cells/tissues, with hydrogel type biopolymeric shells confer them compatibility and the capacity to retain and deliver bioactive substances. The main objective of this work is the development of a new system based on a biocompatible polymer with organic-inorganic structure capable of vectoring support for biologic active agents (L: -asparaginase, e.g.

Nanostructured Biomaterials with Controlled Properties Synthesis and Characterization.

Magnetic nanoparticles were obtained using an adjusted Massart method and were covered in a layer-by-layer technique with hydrogel-type biocompatible shells, from chitosan and hyaluronic acid. The synthesized nanocomposites were characterized using dynamic light scattering, transmission electron microscopy, and Fourier transformed infrared spectroscopy. Biocompatibility of magnetic nanostructures was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) cell proliferation assay, swelling tests, and degradation tests.

Screen-printed electrodes with electropolymerized Meldola Blue as versatile detectors in biosensors.

Electropolymerization of Meldola Blue was carried out by cyclic voltammetry in the range from -0.6 to +1.4 V vs.