Products of Selenite/Thiols Interaction Have Reducing Properties, Cleave Plasmid DNA and Decrease Rat Blood Pressure and Tension of Rat Mesenteric Artery.

Selenium compounds exert their antioxidant activity mostly when the selenium atom is incorporated into selenoproteins. In our work, we tested the possibility that selenite itself interacts with thiols to form active species that have reducing properties. Therefore, we studied the reduction of 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazol-1-yloxy-3-oxide radical (•cPTIO), damage of plasmid DNA (pDNA), modulation of rat hemodynamic parameters and tension of isolated arteries induced by products of interaction of selenite with thiols. We found that the products of selenite interaction with thiols had significant reducing properties that could be attributed mainly to the selenide and that selenite had catalytic properties in the access of thiols. The potency of thiols to reduce •cPTIO in the interaction with selenite was cysteine > homocysteine > glutathione reduced > N-acetylcysteine. Thiol/selenite products cleaved pDNA, with superoxide dismutase enhancing these effects suggesting a positive involvement of superoxide anion in the process. The observed •cPTIO reduction and pDNA cleavage were significantly lower when selenomethionine was used instead of selenite. The products of glutathione/selenite interaction affected several hemodynamic parameters including rat blood pressure decrease. Notably, the products relaxed isolated mesenteric artery, which may explain the observed decrease in rat blood pressure. In conclusion, we found that the thiol/selenite interaction products exhibited significant reducing properties which can be used in further studies of the treatment of pathological conditions caused by oxidative stress. The results of decreased rat blood pressure and the tension of mesenteric artery may be perspective in studies focused on cardiovascular disease and their prevention.

Selective Tumor Hypoxia Targeting Using M75 Antibody Conjugated Photothermally Active MoOx Nanoparticles.

Photothermal therapy (PTT) mediated at the nanoscale has a unique advantage over currently used cancer treatments, by being spatially highly specific and minimally invasive. Although PTT combats traditional tumor treatment approaches, its clinical implementation has not yet been successful. The reasons for its disadvantage include an insufficient treatment efficiency or low tumor accumulation. Here, we present a promising new PTT platform combining a recently emerged two-dimensional (2D) inorganic nanomaterial, MoOx, and a tumor hypoxia targeting element, the monoclonal antibody M75. M75 specifically binds to carbonic anhydrase IX (CAIX), a hypoxia marker associated with many solid tumors with a poor prognosis. The as-prepared nanoconjugates showed highly specific binding to cancer cells expressing CAIX while being able to produce significant photothermal yield after irradiation with near-IR wavelengths. Small aminophosphonic acid linkers were recognized to be more effective over the combination of poly(ethylene glycol) chain and biotin-avidin-biotin bridge in constructing a PTT platform with high tumor-binding efficacy. The in vitro cellular uptake of nanoconjugates was visualized by high-resolution fluorescence microscopy and label-free live cell confocal Raman microscopy. The key to effective cancer treatment may be the synergistic employment of active targeting and noninvasive, tumor-selective therapeutic approaches, such as nanoscale-mediated PTT. The use of active targeting can streamline nanoparticle delivery increasing photothermal yield and therapeutic success.

UV-Cured Green Polymers for Biosensorics: Correlation of Operational Parameters of Highly Sensitive Biosensors with Nano-Volumes and Adsorption Properties.

The investigated polymeric matrixes consisted of epoxidized linseed oil (ELO), acrylated epoxidized soybean oil (AESO), trimethylolpropane triglycidyl ether (RD1), vanillin dimethacrylate (VDM), triarylsulfonium hexafluorophosphate salts (PI), and 2,2-dimethoxy-2-phenylacetophenone (DMPA). Linseed oil-based (ELO/PI, ELO/10RD1/PI) and soybean oil-based (AESO/VDM, AESO/VDM/DMPA) polymers were obtained by cationic and radical photopolymerization reactions, respectively. In order to improve the cross-linking density of the resulting polymers, 10 mol.% of RD1 was used as a reactive diluent in the cationic photopolymerization of ELO. In parallel, VDM was used as a plasticizer in AESO radical photopolymerization reactions. Positron annihilation lifetime spectroscopy (PALS) was used to characterize vegetable oil-based UV-cured polymers regarding their structural stability in a wide range of temperatures (120-320 K) and humidity. The polymers were used as laccase immobilization matrixes for the construction of amperometric biosensors. A direct dependence of the main operational parameters of the biosensors and microscopical characteristics of polymer matrixes (mostly on the size of free volumes and water content) was established. The biosensors are intended for the detection of trace water pollution with xenobiotics, carcinogenic substances with a very negative impact on human health. These findings will allow better predictions for novel polymers as immobilization matrixes for biosensing or biotechnology applications.

The Potential Application of Magnetic Nanoparticles for Liver Fibrosis Theranostics.

Liver fibrosis is a major cause of morbidity and mortality worldwide due to chronic liver damage and leading to cirrhosis, liver cancer, and liver failure. To date, there is no effective and specific therapy for patients with hepatic fibrosis. As a result of their various advantages such as biocompatibility, imaging contrast ability, improved tissue penetration, and superparamagnetic properties, magnetic nanoparticles have a great potential for diagnosis and therapy in various liver diseases including fibrosis. In this review, we focus on the molecular mechanisms and important factors for hepatic fibrosis and on potential magnetic nanoparticles-based therapeutics. New strategies for the diagnosis of liver fibrosis are also discussed, with a summary of the challenges and perspectives in the translational application of magnetic nanoparticles from bench to bedside.

Microporous carbon fibers as electroconductive immobilization matrixes: Effect of their structure on operational parameters of laccase-based amperometric biosensor.

In this study, we describe the fabrication of sensitive biosensor for the detection of phenolic substrates using laccase immobilized onto two types of microporous carbon fibers (CFs). The main characteristics of microporous CFs used for preparation of biosensors are given. Two CFs were characterized by different specific surface area, CFA (<1 m2·g-1) and CFB (1448 m2·g-1), but with comparable size of the micropores estimated by positron annihilation lifetime spectroscopy. The structural analysis was shown that CFA is formed by thin interwoven fibers forming a highly porous structure, as well as CFB - by granular formations with uneven edges that shape a cellulose membrane of lower porosity. The results of amperometric analysis revealed that the laccase-bound CFs possesses better electrochemical behavior for laccase than non-modified rod carbon electrodes (control). Using chronoamperometric analysis, the operational parameters of the CFs-modified bioelectrodes were compared to control bioelectrodes. The bioelectrodes based on CFs have demonstrated 2.4-2.7 folds enhanced maximal current at substrate saturation (Imax) values, 1.2-1.4 folds increased sensitivity and twice wide linearity compared with control bioelectrodes. The sensitivity of the developed CFs-based bioelectrodes was improved compared with the laccase-bound electrodes, described in literature. The developed biosensor was tested for catechol analysis in the real communal wastewater sample.

Molecular probe dynamics and free volume heterogeneities in n-propanol confined in a regular MCM-41 matrix by ESR and PALS.

A combined investigation of the spin probe TEMPO mobility and the free volume holes in n-propanol (n-PrOH) confined in a regular virgin MCM-41 matrix by means of ESR or PALS techniques, respectively, is reported. Dynamics of spin probe TEMPO alters at several characteristic ESR temperatures which are close to the characteristic PALS ones reflecting the changes in o-Ps annihilation and the related free volume. Correlations between these characteristic ESR and PALS temperatures indicate the common physical origins of the respective changes in the free volume expansion and the TEMPO mobility in the confined liquid n-PrOH. The significant difference in dynamic heterogeneity of TEMPO after confinement and free volume dispersion reflect the strongly altered structural-dynamic relationships in the confined n-PrOH medium with respect to the bulk situation.

Carbon Quantum Dots Modified Polyurethane Nanocomposite as Effective Photocatalytic and Antibacterial Agents.

Development of new types of antibacterial coatings or nanocomposites is of great importance due to widespread multidrug-resistant infections including bacterial infections. Herein, we investigated biocompatibility as well as structural, photocatalytic, and antibacterial properties of photoactive hydrophobic carbon quantum dots/polyurethane nanocomposite. The swell-encapsulation-shrink method was applied for production of these nanocomposites. Hydrophobic carbon quantum dots/polyurethane nanocomposites were found to be highly effective generator of singlet oxygen upon irradiation by low-power blue light. Analysis of conducted antibacterial tests on Staphyloccocus aureus and Escherichia coli showed 5-log bactericidal effect of these nanocomposites within 60 min of irradiation. Very powerful degradation of dye (rose bengal) was observed within 180 min of blue light irradiation of the nanocomposites. Biocompatibility studies revealed that nanocomposites were not cytotoxic against mouse embryonic fibroblast cell line, whereas they showed moderate cytotoxicity toward adenocarcinomic human epithelial cell line. Minor hemolytic effect of these nanocomposites toward red blood cells was revealed.