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Some biologically active substances are unstable and poorly soluble in aqueous media, at the same time exhibiting low bioavailability. The incorporation of these biologically active compounds into the structure of a lipid-based lyotropic liquid crystalline phase or nanoparticles can increase or improve their stability and transport properties, subsequent bioavailability, and applicability in general. The aim of this short overview is (1) to clarify the principle of self-assembly of lipidic amphiphilic molecules in an aqueous environment and (2) to present lipidic bicontinuous cubic and hexagonal phases and their current biosensing (with a focus on electrochemical protocols) and biomedical applications. Graphical Abstract

This work explores the interaction of 9/10-nitro-oleic acid (NO

International audience; This work reports on the preparation and structural characterization of flavo[7]helicene 1 (flavin-[7]helicene conjugate), which was subsequently characterized at the molecular level in either an aqueous environment or an organic phase, at the supramolecular level in the form of polymeric layers, and also embedded in a lipidic mesophase environment to study the resulting properties of such a hybrid relative to its parent molecules. The flavin benzo[g]pteridin-2,4-dione (isoalloxazine) was selected for conjugation because of its photoactivity and reversible redox behavior. Compound 1 was prepared from 2-nitroso[6]helicene and 6-methylamino-3-methyluracil, and characterized using common structural and spectroscopic tools: circular dichroism (CD), circularly polarized luminescence (CPL) spectroscopy, cyclic voltammetry (CV), and DFT quantum calculations. In addition, a methodology that allows the loading of 1 enantiomers into an internally nanostructured lipid (1-monoolein) matrix was developed.

In this contribution, a comprehensive study of the redox transformation, electronic structure, stability and photoprotective properties of phytocannabinoids is presented. The non-psychotropic cannabidiol (CBD), cannabigerol (CBG), cannabinol (CBN), cannabichromene (CBC), and psychotropic tetrahydrocannabinol (THC) isomers and iso-THC were included in the study. The results show that under aqueous ambient conditions at pH 7.4, non-psychotropic cannabinoids are slight or moderate electron-donors and they are relatively stable, in the following order: CBD > CBG ≥ CBN > CBC. In contrast, psychotropic Δ9-THC degrades approximately one order of magnitude faster than CBD. The degradation (oxidation) is associated with the transformation of OH groups and changes in the double-bond system of the investigated molecules. The satisfactory stability of cannabinoids is associated with the fact that their OH groups are fully protonated at pH 7.4 (pKa is ≥ 9). The instability of CBN and CBC was accelerated after exposure to UVA radiation, with CBD (or CBG) being stable for up to 24 h. To support their topical applications, an in vitro dermatological comparative study of cytotoxic, phototoxic and UVA or UVB photoprotective effects using normal human dermal fibroblasts (NHDF) and keratinocytes (HaCaT) was done. NHDF are approx. twice as sensitive to the cannabinoids’ toxicity as HaCaT. Specifically, toxicity IC50 values for CBD after 24 h of incubation are 7.1 and 12.8 μM for NHDF and HaCaT, respectively. None of the studied cannabinoids were phototoxic. Extensive testing has shown that CBD is the most effective protectant against UVA radiation of the studied cannabinoids. For UVB radiation, CBN was the most effective. The results acquired could be used for further redox biology studies on phytocannabinoids and evaluations of their mechanism of action at the molecular level. Furthermore, the UVA and UVB photoprotectivity of phytocannabinoids could also be utilized in the development of new cannabinoid-based topical preparations.

Covalent modifications of thiol and amine groups may control the function of proteins involved in the regulatory and signaling pathways of the cell. In this study, we developed a simple cysteamine assay which can be used to study the reactivity of electrophilic compounds towards primary amine and thiol groups in an aqueous environment. The detection principle is based on the electrochemical, photometrical and mass spectrometric analyses of cysteamine (2-aminoethanethiol) as the molecular probe. This technique is useful for studying the reaction kinetics of electrophiles with thiol (SH) and amino (NH2) groups. The decrease in analytical responses of cysteamine was monitored to evaluate the reactivity of three electrophilic activators of the Nrf2 pathway, which mediates the cellular stress response. The SH-reactivity under cell-free conditions of the tested electrophiles decreased in the following order: 4-hydroxy-2-nonenal ≥ nitro-oleic acid > sulforaphane. However, as shown in RAW264.7 cells, the tested compounds activated Nrf2-dependent gene expression in the opposite order: sulforaphane > nitro-oleic acid ≥ 4-hydroxy-2-nonenal. Although other factors in addition to chemical reactivity play a role in biological systems, we conclude that this cysteamine assay is a useful tool for screening potentially bioactive electrophiles and for studying their reactivity at a molecular level.

Since the flat serve (FS) minimizes the ball spin and kick serve (KS) combined topspin and sidespin, this systematic review aimed to explore the ball impact location (BI) within the FS and KS at the professional men, junior men, and women tennis players. The PRISMA guideline was used, and the original articles were searched in Scopus, Web of Science, and PubMed. The means and standard deviations computed from the distance of BI from the origin within the FS and KS on the x, y, and z axes (global coordinate system) were normalized by the participants’ height and weighted by the number of participants in one-way ANOVA. Ten articles with a pooled sample of 133 males and 51 females aged 11–25 were included. The professional men had more stable BI on the x-axis within the FS by 56% (p < 0.001), within the KS by 58% (p < 0.001), and on the y-axis within the KS by 90% (p < 0.001) than junior men. The professional and junior men had the BI more leftwards from the origin on the x-axis within the KS by 188% (p < 0.001) and 88% (p < 0.001), respectively than within the FS.

The development of clinically applicable portable sensors and multiplex protein biomarker assays is one of the most important goals of laboratory medicine today. Sensing strategies based on electrochemical devices are discussed in this overview, with special emphasis on detection principles derived from voltammetry, electrogenerated chemiluminescence, bipolar electrochemistry and impedance-based measurements. Up-to-date examples of electrochemical methods in biomedical research and development are highlighted here, including critical evaluation and future directions of the analysis, development and validation of new protein biomarkers.

Lipid nitroalkenes – nitro-fatty acids (NO2–FAs) are formed in vivo via the interaction of reactive nitrogen species with unsaturated fatty acids. The resulting electrophilic NO2–FAs play an important role in redox homeostasis and cellular stress response. This study investigated the physicochemical properties and reactivity of two NO2–FAs: 9/10-nitrooleic acid (1) and its newly prepared 1-monoacyl ester, (E)-2,3-hydroxypropyl 9/10-nitrooctadec-9-enoate (2), both synthesized by a direct radical nitration approach. Compounds 1 and 2 were investigated in an aqueous medium and after incorporation into lipid nanoparticles prepared from 1-monoolein, cubosomes 1@CUB and 2@CUB. Using an electrochemical analysis and LC-MS, free 1 and 2 were found to be unstable under acidic conditions, and their degradation occurred in an aqueous environment within a few minutes or hours. This degradation was associated with the production of the NO radical, as confirmed by fluorescence assay. In contrast, preparations 1@CUB and 2@CUB exhibited a significant increase in the stability of the loaded 1 and 2 up to several days to weeks. In addition to experimental data, density functional theory-based calculation results on the electronic structure and structural variability (open and closed configuration) of 1 and 2 were obtained. Finally, experiments with a human HaCaT keratinocyte cell line demonstrated the ability of 1@CUB and 2@CUB to penetrate through the cytoplasmic membrane and modulate cellular pathways, which was exemplified by the Keap1 protein level monitoring. Free 1 and 2 and the cubosomes prepared from them showed cytotoxic effect on HaCaT cells with IC50 values ranging from 1 to 8 μM after 24 h. The further development of cubosomal preparations with embedded electrophilic NO2–FAs may not only contribute to the field of fundamental research, but also to their application using an optimized lipid delivery vehicle., Highlights • Nitro-fatty acids (NO2–FAs) are bioactive electrophiles and new drug candidates. • The study focused on endogenous NO2-oleic acid and its glycerol ester. • Cubosomes are lipid nanoparticles stabilizing the incorporated NO2–FAs. • Applicability of NO2-FA-loaded cubosomes was tested on human HaCaT keratinocytes.

This opinion is focused on the electrochemistry of peptides utilised in biological and technological processes. The redox behaviour of peptides important in biomedicine, neuropeptides and antimicrobial peptides is highlighted. In addition to peptides composed of essential amino acids, peptide-mimetic molecules such as peptide nucleic acid and artificial peptidic wires transferring protons and electrons are reviewed. The application of electrochemistry for the research of peptide–membrane and peptide–surface interactions is also discussed.

The first racemization-stable helicene derivatives fluorinated at terminal rings, 1,2,3,4-tetrafluoro[6]helicene (6) and 1,2,3,4,13,14,15,16-octafluoro[6]helicene (15), were synthesized via the Wittig reaction followed by oxidative photocyclization in an overall yield of 41% of 6 and 76% of 15. The changed electronic structure in fluorinated helicenes was reflected in a slight shift of UV-vis absorption, fluorescence excitation, and emission spectra maxima when compared to unsubstituted [6]helicene. Cyclic voltammetry revealed a moderate decrease in the HOMO-LUMO gap with increasing fluorination. The specific rotation of tetrafluoro[6]helicene 6 enantiomers was found to be approximately 25% lower than that of unsubstituted [6]helicene. The theoretical study of the racemization barrier suggested a reasonable shift toward higher energy with increasing fluorination. The increasing fluorination also significantly affected the intermolecular interactions in the crystal lattice. The observed CH···F interactions led to the formation of 1D-molecular chains in the crystal structures of both fluorinated helicenes.

Summary The electrochemistry of membrane proteins allows us to examine the association of proteins with membranes and low-molecular ligands, such as drugs, toxins and others. In addition, electrochemical methods are applicable for the quantification of transport phenomena, for monitoring the change in the structure of the protein, and determining its catalytic activity if the protein is an enzyme. In addition to approaches based on the concept of protein film voltammetry, methods based on the direct redox transformations or electrocatalytic reactions of the amino acid residues in the protein structure could be used. The above areas of interest fall under basic research, which is the main subject of this paper. However, the utilization of new immobilization strategies for proteins and the application of redox active polymers is an important part of the development of new biosensors and the construction of devices employing the principles of bioelectrocatalysis.

In the last years, several key reuse attacks were proposed against Round 2 candidates of the NIST Post-Quantum Cryptography Standardization Process. In these attacks, the adversary has access to the key mismatch oracle which tells her if a given ciphertext decrypts to a given message under the targeted secret key. One of the so far non-targeted candidates is ThreeBears, which is a key encapsulation mechanism based on the integer module learning with errors (I-MLWE) problem. In this paper, we present a first key mismatch attack against the ThreeBears cryptosystem. Our attack recovers the whole secret key with probability of 100% and requires about \(2^{11}\) queries on average. Besides that, we use our technique to target other Round 2 candidates Frodo and Round5, and we improve the state-of-the-art results for them.

Fatty acid nitroalkenes (NO2-FA) are endogenously-generated products of the reaction of metabolic and inflammatory-derived nitrogen dioxide (.NO2) with unsaturated fatty acids. These species mediate signaling actions and induce adaptive responses in preclinical models of inflammatory and metabolic diseases. The nitroalkene substituent possesses an electrophilic nature, resulting in rapid and reversible reactions with biological nucleophiles such as cysteine, thus supporting post-translational modifications (PTM) of proteins having susceptible nucleophilic centers. These reactions contribute to enzyme regulation, modulation of inflammation and cell proliferation and the regulation of gene expression responses. Herein, focus is placed on the reduction-oxidation (redox) characteristics and stability of specific NO2-FA regioisomers having biological and clinical relevance; nitro-oleic acid (NO2-OA), bis-allylic nitro-linoleic acid (NO2-LA) and the conjugated diene-containing nitro-conjugated linoleic acid (NO2-cLA). Cyclic and alternating-current voltammetry and chronopotentiometry were used to the study of reduction potentials of these NO2-FA. R–NO2 reduction was observed around −0.8 V (vs. Ag/AgCl/3 M KCl) and is related to relative NO2-FA electrophilicity. This reduction process could be utilized for the evaluation of NO2-FA stability in aqueous milieu, shown herein to be pH dependent. In addition, electron paramagnetic resonance (EPR) spectroscopy was used to define the stability of the nitroalkene moiety under aqueous conditions, specifically under conditions where nitric oxide (.NO) release could be detected. The experimental data were supported by density functional theory calculations using 6–311++G (d,p) basis set and B3LYP functional. Based on experimental and computational approaches, the relative electrophilicities of these NO2-FA are NO2-cLA >> NO2-LA > NO2-OA. Micellarization and vesiculation largely define these biophysical characteristics in aqueous, nucleophile-free conditions. At concentrations below the critical micellar concentration (CMC), monomeric NO2-FA predominate, while at greater concentrations a micellar phase consisting of self-assembled lipid structures predominates. The CMC, determined by dynamic light scattering in 0.1 M phosphate buffer (pH 7.4) at 25 °C, was 6.9 (NO2-LA) 10.6 (NO2-OA) and 42.3 μM (NO2-cLA), respectively. In aggregate, this study provides new insight into the biophysical properties of NO2-FA that are important for better understanding the cell signaling and pharmacological potential of this class of mediators., Highlights • Nitro-fatty acids (NO2-FA) are electrophilic mediators of redox-regulated signaling reactions. • The relative electrophilicity of 18 carbon chain length NO2-FA is NO2-cLA » NO2-LA > NO2-OA. • Critical micellar concentrations at pH 7.4 were 10.6, 6.9 and 42.3 μM for NO2-OA, NO2-LA and NO2-cLA, respectively. • Nitrogen dioxide (.NO2) rapidly reacts with unsaturated FA and yields more stable bioactive NO2-FA byproducts.

The screening of new molecules with high electron-donor properties is important for the design of new bioactive and technologically applicable substances. Here we propose diferulate (1), (Z)-2-(5-((E)-2-carboxyvinyl)-2-hydroxy-3-methoxyphenyl)-3-(4-hydroxy-3-methoxyphenyl)acrylic acid, to be an efficient electron donor which undergoes anodic conversion in aqueous media (pH 7) at around +0.15 V, vs. Ag|AgCl|3 M KCl. The low potential of oxidation of 1 indicates its high electron-donor capacity, which was documented by DPPH and ABTS radical scavenging and anti-lipoperoxidation activity analyses and also supported by in silico approaches. The results showed that compound 1, unlike ferulic acid 2 and the P1 benzofuranone synthetic precursor of 1, exhibits unique antiradical and antioxidant properties compared to trolox 3, which served as the positive control. No cytotoxic effects were observed for 1 in the 1–50 μM range. We conclude that the proposed structure 1 can be used for the further design of molecules whose biological (chemoprotective) activity is associated with high electron-donor properties.

Chirality is a fascinating phenomenon for recent electrochemistry and materials research, allowing for the preparation of detection platforms based on analyte enantiodiscrimination and the development of advanced chiroptical devices and chiral electrodes. In this Viewpoint, we highlight new directions in the field of chiral helical polyaromatic molecules (mainly helicenes) that are useful for the preparation of optically and redox-active polymers and/or self-assembled thin layers, nanostructures and functional electrode surfaces. Instead of the previously reported chiral materials prepared by molecular imprinting, a concept based on the preparation of inherently chiral helicene-based materials with (opto)electrochemical applicability is presented. A short overview of well-established electrochemical methods for the research of chiral molecules is also outlined.

© 2020 The Author(s)., [Introduction]: The importance of biomarkers for pharmaceutical drug development and clinical diagnostics is more significant than ever in the current shift toward personalized medicine. Biomarkers have taken a central position either as companion markers to support drug development and patient selection, or as indicators aiming to detect the earliest perturbations indicative of disease, minimizing therapeutic intervention or even enabling disease reversal. Protein biomarkers are of particular interest given their central role in biochemical pathways. Hence, capabilities to analyze multiple protein biomarkers in one assay are highly interesting for biomedical research. [Areas covered]: We here review multiple methods that are suitable for robust, high throughput, standardized, and affordable analysis of protein biomarkers in a multiplex format. We describe innovative developments in immunoassays, the vanguard of methods in clinical laboratories, and mass spectrometry, increasingly implemented for protein biomarker analysis. Moreover, emerging techniques are discussed with potentially improved protein capture, separation, and detection that will further boost multiplex analyses. [Expert commentary]: The development of clinically applied multiplex protein biomarker assays is essential as multi-protein signatures provide more comprehensive information about biological systems than single biomarkers, leading to improved insights in mechanisms of disease, diagnostics, and the effect of personalized medicine., This paper was funded by the European cooperation in science and technology - COST action No. CA16113 - CliniMARK: ‘good biomarker practice’ to increase the number of clinically validated biomarkers.

We introduce an ergonomic positioning for sonographic scanning of elbow joint where the patient is lying semisupine on the examination bed. This is in contrast with the conventional positioning where the patient is sitting on the edge of the bed or across the table on a chair. Our proposed positioning is more comfortable for both the patient and ultrasound practitioner. It also allows immediate ultrasound-guided injections with lesser risk regarding a vasovagal syncope of the patient.

International audience; Helicenes are polyaromatic compounds with chiral properties useful for many applications in optoelectronics, separation processes, chiral recognition and catalysis. Here we focused on the electrochemistry of carbo[n]helicenes (n=5,6,7). The cyclic voltammograms of racemic mixtures of target compounds in acetonitrile/0.1M tetrabutylammonium perchlorate at a glassy carbon electrode reveal the diffusion-controlled reactions in both anodic and cathodic potential regions. Electrochemical behaviors are different for individual helicenes, [7]helicene undergoes redox transformation easily in comparison to the other investigated compounds, which is in agreement with DFT (density functional theory) calculations. Generally, the multi-component anodic process of helicenes is observable at potentials from +1.5 to +2.5V, leading to the formation of deposited structures (layers) on the electrode surface. The helicenes were electrodeposited onto transparent indium tin oxide (ITO) electrodes and characterized by atomic force microscopy, UV/Vis, Raman spectroscopy and ellipsometry. Finally, the anodic deposition of P and M enantiomers of [6]helicene was performed using ITO substrates, resulting in the formation of enantiopure layers of nanometer thicknesses, as confirmed by circular dichroism spectroscopy. The discovered electrosynthetic procedure opens up a new possibility for the immobilization of chiral helicene layers onto solid supports.

The construction of a cylindrical carbon fiber on-line detector is presented, featuring a novel way of sealing the carbon fiber microelectrode, the design of an interchangeable carbon fiber microelectrode-based flow cell and its interface with data-acquisition electronics. The two-electrode setup was used, where the regeneration of the carbon fiber working electrode surface between analyses was performed using an electrochemical procedure, typically −1/+1 V potential cycling. The detector was incorporated into the flow injection analysis manifold and the applicability of the developed sensing platform tested for monitoring a hexacyanoferrate (II/III) redox probe and the oxidizable compounds trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), uric acid, and l -ascorbic acid, with dehydroascorbic acid as a negative control. Finally, the optimized procedure was utilized for the analysis of human blood serum reductive (antioxidant) capacity based on amperometric sensing and flow injection analysis at a flow rate of 10 μl/min. Amperometric responses for blood serum samples were evaluated for standard deviation, whose average value was estimated to be ±0.3 nA (n = 20). The electrolytic efficiency of the detector was on the order of % units, e.g. 2% for trolox. The flow cell geometry and application of carbon fiber electrodes resulted in the absence of dead volumes and passivation phenomena, in contrast to conventional high-surface-area electrochemical cells. We suppose that the complex technical solution presented here could find a broad range of applications in the on-line monitoring of other reducing low-molecular bioactives and of the redox properties of various body fluids or clinical samples.

Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) is a transmembrane protein that transfers calcium ions from the cytosol of the cell to the lumen of the sarco/endoplasmic reticulum (SR) at the expense of ATP hydrolysis during muscle relaxation. Here we report the electrochemical monitoring of a SERCA1 isoform isolated from rabbit skeletal muscle. The constant-current chronopotentiometric stripping (CPS) analysis was applied for the analysis of solubilized SERCA1 based on a catalytic hydrogen evolution reaction (CHER). Consequently we applied an optimized CPS electrochemical protocol for monitoring the interaction of SERCA1 with the dicarbonyl compounds methylglyoxal, glyoxal and 3‑deoxyglucosone. We observed that SERCA1 readily interacts with methylglyoxal at pH 7.4. Electrochemical analysis showed that 1 mg/ml (9.1 μmol/l) SERCA1 was fully modified by methylglyoxal (3 mmol/l) after 24 h. The dicarbonyl binding decreased the enzyme activity of purified SERCA1 in the following order: methylglyoxal ≫ glyoxal > 3‑deoxyglucosone. The methodology presented here could be used in further studies of the structural integrity and intermolecular interactions of membrane transporters and the study of their oxidative modifications, carbonylation or glycoxidation.

The lipidic liquid-crystalline cubic phase (LCP) is a membrane-mimetic material useful for the stabilization and structural analysis of membrane proteins. Here, we focused on the incorporation of the membrane ATP-hydrolysing sodium/potassium transporter Na + /K + -ATPase (NKA) into a monoolein-derived LCP. Small-angle X-ray scattering was employed for the determination of the LCP structure, which was of Pn3m symmetry for all the formulations studied. The fully characterized NKA-LCP material was immobilized onto a glassy carbon electrode, forming a highly stable enzyme electrode and a novel sensing platform. A typical NKA voltammetric signature was monitored via the anodic reaction of tyrosine and tryptophan residues. The in situ enzyme activity evaluation was based on the ability of NKA to transform ATP to ADP and free phosphate, the latter reacting with ammonium molybdate to form the ammonium phosphomolybdate complex under acidic conditions. The square-wave voltammetric detection of phosphomolybdate was performed and complemented with spectrophotometric measurement at 710 nm. The anodic voltammetric response, corresponding to the catalytic ATP-hydrolysing function of NKA incorporated into the LCP, was monitored at around + 0.2 V vs. Ag/AgCl in the presence or absence of ouabain, a specific NKA inhibitor. NKA incorporated into the LCP retained its ATP-hydrolysing activity for 7 days, while the solubilized protein became practically inactive. The novelty of this work is the first incorporation of NKA into a lipidic cubic phase with consequent enzyme functionality and stability evaluation using voltammetric detection. The application of LCPs could also be important in the further development of new membrane protein electrochemical sensors and enzyme electrodes.

A library of thirty two 3,4-diphenylfuranones related to both combretastatin A-4 and antifungal 5-(acyloxymethyl)-3-(halophenyl)-2,5-dihydrofuran-2-ones was prepared. Cytotoxic effects on a panel of cancer and normal cell lines and antiinfective activity were evaluated, and the data were complemented with tests for the activation of caspase 3 and 7. High cytotoxicity was observed in some of the halogenated analogues, eg. 3-(3,4-dichlorophenyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one with IC50 0.12–0.23 μM, but the compounds were also highly toxic against non-malignant control cells. More importantly, notable antibacterial activity indicating G+ selectivity has been found in the 3,4-diarylfuranone class of compounds for the first time. Hydroxymethylation of furanone C5 knocked out cytotoxic effects (up to 40 μM) while maintaining significant activity against Staphylococcus strains in some derivatives. MIC95 of the most promising compound, 3-(4-bromophenyl)-5,5-bis(hydroxymethyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one against S. aureus strain ATCC 6538 was 0.98 μM (0.38 μg/mL) and 3.9 μM (1.52 μg/mL) after 24 and 48 h, respectively.

New materials bearing thiophene and helicene moieties were prepared by a potential-driven on/off switch strategy onto the surface of glassy carbon and indium tin oxide substrates. Specifically, a 3-([7]helicen-9-yl)-thiophene hybrid monomer was electrooxidized in acetonitrile by cyclic voltammetry with anodic potential limits of +1.5 V or +2.5 V, resulting in a conductive and non-conductive polymer, respectively. The electrochemical findings were supplemented by microscopy investigations; UV-Vis, fluorescence and vibrational spectroscopies; 1H NMR spectroscopy; ellipsometry measurements and computational chemistry. The electrodeposited polymers could be used for the further development of materials applicable in organic electronics, optoelectronics and sensing technologies.