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Several probes containing benzothiazole-guided conjugated systems (BGCS) were designed and synthesized, and two molecules (BGCS5 and BGCS6) of which were discovered as selective probes targeting c-MYC Pu22 G-quadruplex DNA. The fluorescence intensity of BGCS5 and BGCS6 in the presence of c-MYC Pu22 far exceeds that of the typical G4 probe TO1. Especially, the fluorescence of BGCS6 increased almost 193-fold in the presence of c-MYC Pu22 G4 compared to that alone in aqueous buffer condition with almost no fluorescence and 10–30 folds than those in the presence of other DNAs, which will be useful tools for disease detection in mammals.

We developed a novel Pd-catalysed enantioselective synthesis of C–N bonds using the chiral scaffold of DNA. The non-covalently linked [Pd(phen)(OAc)2] with st-DNA catalysed the Markonicov hydroamination of β-nitrostyrene with methoxyamine for the first time with >75% enantiomeric excess (ee) in an aqueous buffer (pH 7.4) at room temperature.

The interaction between an aqueous phthalate buffer and the rare earth metal europium(III) was investigated to demonstrate the effect of buffer complexation of Eu on solvent extraction slope analys...

Recently, it was reported that tetra-peptides cyclized via lactam bond between the amino terminus and a glutamic residue in position 4 (termed here N-lock) can nucleate helix formation in longer peptides. We applied such strategy to derive N-locked covalent BH3 peptides that were designed to selectively target the anti-apoptotic protein Bfl-1. The resulting agents were soluble in aqueous buffer and displayed a remarkable (low nanomolar) affinity for Bfl-1 and cellular activity. The crystal structure of the complex between such N-locked covalent peptide and Bfl-1 provided insights on the geometry of the N-locking strategy and of the covalent bond between the agent and Bfl-1.

In this study, the interaction between Luteolin and urease was made at 300 K in aqueous buffer solutions using isothermal titration calorimetry. The extended solvation model was used to calculate the solvation parameters. Moreover, to determine the interaction of Luteolin with Jack Bean Urease (JBU), a molecular docking process was performed. The purpose of this investigation was to measure the inhibitory effects of Luteolin on the activity and structure of urease. Molecular docking analysis confirmed the extended solvation model.

The influence of temperature and concentration of L-histidine on the heat capacity properties of its aqueous buffer solutions was studied by differential scanning calorimetry. The investigations were carried out in aqueous buffer solutions (pH 7.4) containing monobasic sodium phosphate and dibasic sodium phosphate, which brings the environment closer to the conditions of real biological systems. The pH values of the solutions were fixed with a digital pH meter Mettler Toledo, model Five-Easy (Switzerland). The differential scanning microcalorimeter SCAL-1 (Biopribor, Pushchino, Russia) was used for measure the specific heat capacity of the system under study. It was equipped with Peltier thermoelectric elements, two measuring glass cells with an internal volume of 0.377 cm3, as well as a computer terminal and software for calculating heat capacity. The standard error of measurement of the specific heat for the studied solutions was within ±7·10-3 J·K-1·g-1. The experimental values of the specific heat of solutions of the amino acid in a phosphate buffer solvent in the temperature range (283.15 – 343.15) K were obtained. The concentration of histidine was varied from (0.00215 to 0.03648) mol·kg-1. All the studied solutions were prepared by the gravimetric method using Sartorius-ME215S scales (with a weighing accuracy of 1·10-5 g). The apparent molar heat capacities of L-histidine in the buffer solution, as well as its partial molar heat capacities at infinite dilution, were determined. The calculated molar parameters increase with an increase in both temperature and amino acid concentration. It was shown that the partial molar heat capacities transfers of L-histidine from water to the buffer solution have positive values in the temperature range studied. The results are discussed on base of the Gurney model.

The palladium-catalyzed Tsuji–Trost reaction has been extensively studied under synthetically relevant conditions (millimolar concentrations of substrates and catalyst, aprotic solvents, no additiv...

Protein adsorption is of fundamental importance for bioseparation engineering applications. In this work, a series of mesoporous TiO2 with various geometric structures and different aqueous buffer solutions were prepared as platforms to investigate the effects of the surface geometry and ionic strength on the protein adsorptive behavior. The surface geometry of the TiO2 was found to play a dominant role in the protein adsorption capacity when the ionic strength of buffer solutions is very low. With the increase in ionic strength, the effect of the geometric structure on the protein adsorption capacity reduced greatly. The change of ionic strength has the highest significant effect on the mesoporous TiO2 with large pore size compared with that with small pore size. The interaction between the protein and TiO2 measured with atomic force microscopy further demonstrated that the adhesion force induced by the surface geometry reduced with the increase in the ionic strength. These findings were used to guide the detection of the retention behavior of protein by high-performance liquid chromatography, providing a step forward toward understanding the protein adsorption for predicting and controlling the chromatographic separation of proteins.

Interactions between L-phenylalanine (Phe) and uracyl (Ura) in an aqueous buffer solution (pH 7.35) are analyzed via densimetry and differential scanning calorimetry. Experimental values of the density and specific heat capacity of Ura–buffer, Phe–buffer, and Phe–Ura–buffer systems are obtained at T = (293.15, 303.15, 313.15, and 323.15) K, Ura concentrations of 0.0040 to 0.0365 mol kg−1, and a constant Phe concentration of 0.0120 mol kg−1. It is shown that the interaction between Phe and Ura is accompanied by the formation of a complex with the composition 1 : 2. It is established that the partial molar properties of Ura when it is transferred from the buffer to the buffer Phe solution are positive for the volume and negative for the heat capacity in the investigated range of temperatures. The final results are discussed using the Gurney model.

The modification of peptides and proteins has emerged as a powerful means to efficiently prepare high value bioconjugates for a range of applications in chemical biology and for the development of next-generation therapeutics. Herein, we report a novel method for the chemoselective late-stage modification of peptides and proteins at cysteine in aqueous buffer with suitably functionalised diaryliodonium salts, furnishing stable thioether-linked synthetic conjugates. The power of this new platform is showcased through the late-stage modification of the affibody zEGFR and the histone protein H2A., New operationally simple platform for the chemoselective arylation of cysteine in peptides and proteins to access a variety of high value bioconjugates.

Stable organic radicals have been of great academic interest not only in the context of fundamental understanding of reactive intermediates but also because of their numerous applications as functional materials. Apart from the early examples of triphenylmethyl and TEMPO derivatives, reports on air- and water-stable organic radicals are scarce, and their development remains a challenge. Herein, we present the design and synthesis of a novel organic radical based on a 1,2-dicarbonyl scaffold supported by N-heterocyclic carbenes (NHCs). The presented radical cations exhibit remarkable stability toward various harsh conditions, such as the presence of reactive chemicals (reductants, oxidants, strong acids, and bases) or high temperatures, by far exceeding the stability of triphenylmethyl and TEMPO radicals. In addition, physiological conditions including aqueous buffer and blood serum are tolerated. The steric and electronic stabilization provided by the two NHC moieties enabled the successful design of the highly stable radical.

For preparing a CsCl density gradient one typically mixes a high-density solution of CsCl (7.163 M) with an aqueous buffer solution to reach a target density. For DNA separation in SIP studies this is typically 1.725 g ml-1. Despite the simplicity of the problem, different formulae appeared in the literature, leading to slightly different end values. Most notably, the famous publication by \citealp{Neufeld_2007} uses a constant---1.52---instead of a variable that would represent the density of the mixture. The source of this constant appears to be from the classical book Centrifugal Separations: Molecular and Cell Biology by \citealp{1985}, where it is used for a specific case only.While the practical implications are small so long as one tries to create a solution with a density of 1.725 g ml-1 (although the resulting value is still wrong), the deviations become significant the further the target density deviates from this value.

We describe here a supramolecular sensing system for the array-based classification of biologically relevant mono-, di-, and tri-phosphates in aqueous buffer. The system is based on a colorimetric indicator displacement assay (IDA) with six sensor elements. Each sensor element is comprised of an equimolar cyclic peptide-colorimetric indicator ensemble. Correct classification of the eleven analytes into mono-, di-, tri-, or pyrophosphate was achieved through both principal component analysis (PCA) and linear discriminant analysis (LDA).

A large kinetic isotope effect (KIE, kH/kD) of 12.8 was observed for the hydrogen-transfer reaction from ascorbic acid to 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO˙) in a phosphate buffer solution (0.05 M, pH/pD 7.0) at 298 K. The isotopic difference in the activation energies (6.8 kJ mol-1) determined from the temperature dependence of the KIE suggests that quantum mechanical tunneling may partly play a role in the reaction, although the isotopic ratio of the Arrhenius prefactor (AH/AD = 0.86) is within the semiclassical limits.

Formaldehyde (FA) is endogenously produced in living systems through a variety of biological processes and has been implicated in many pathological conditions. Detection tools for biological FA are therefore of great interest. Reported here are novel activity-based genetically encoded fluorescent and luminescent probes for detecting FA in aqueous solutions and living mammalian cells. A FA-reactive lysine analogue, PrAK, was site-specifically incorporated into the essential lysine sites of enhanced green fluorescent protein (EGFP) and firefly luciferase (fLuc) to afford fluorescent and luminescent FA probes, respectively. FA selectively reacts with PrAK residues on EGFP and fLuc through a 2-aza-Cope rearrangement, resulting in fluorescence and luminescence turn-on responses, respectively, to FA selectively over potentially interfering reactive species in aqueous buffer. Moreover, the genetically encoded probes are capable of visualizing FA at physiologically relevant levels in living mammalian cells by fluorescence and luminescence imaging, demonstrating their potential as new tools to explore FA biology.

Fluorescent scriptaid analogues with excellent HDAC6 selectivity (HDAC1/6 > 500) and potency (HDAC6 IC50

Small molecules, including natural compounds, in aqueous buffer that self-associate into colloidal aggregates is the main cause of false results in the early stage of drug discovery. Here we reported resonant waveguide grating (RWG) based assays to identify natural compound aggregation and characterize its influence on membrane receptors in living cells. We first applied a cell-free aggregation assay to determine compound critical aggregation concentration (CAC) values. Then we characterized the aggregators' influence on membrane receptors using three types of dynamic mass redistribution (DMR) assays. Results showed that colloidal aggregates may cause false activity in DMR desensitization assays; some of the false activities can be implied by the large response in DMR agonism assays and can further be identified by DMR antagonism assays. Furthermore, the aggregation mechanism was confirmed by addition of 0.025% tween-80, with cell signals attenuated and potency decreased. Finally, these observations were used for aggregate examination and promiscuity investigation of a traditional herbal medicine, Rhodiola rosea, which ultimately led to the revealing of the true target and reduced the risk of a bioactivity tracking process at the very first stage. This study highlights that the RWG based assays can be used as practical tools to distinguish between real and false hits to provide reliable results in the early stage of drug discovery.

Flower-shaped organic-inorganic hybrid nanostructures, termed nanoflowers, have received considerable recent attention as they possess greatly enhanced activity, stability, durability, and even selectivity of entrapped organic biomolecules, which are much better than those from the conventional methods. They can be synthesized simply via co-incubation of organic and inorganic components in aqueous buffer at room temperature and yield hierarchical nanostructures with large surface-to-volume ratios, allowing for low-cost production by easy scale-up, as well as the high loading capacity of biomolecules without severe mass transfer limitations. Since a pioneering study reported on hybrid nanoflowers prepared with protein and copper sulfate, many other organic and inorganic components, which endow nanoflowers with diverse functionalities, have been employed. Thanks to these features, they have been applied in a diverse range of areas, including biosensors and biocatalysis. To highlight the progress of research on organic-inorganic hybrid nanoflowers, this review discusses their synthetic methods and mechanisms, structural and biological characteristics, as well as recent representative applications. Current challenges and future directions toward the design and development of multi-functional nanoflowers for their widespread utilization in biotechnology are also discussed.

Background. Heart valve bioprostheses made from glutaraldehyde-treated bovine and porcine pericardia are widely used in open and transcatheter valve surgeries. However, the glutaraldehyde cross-linkage leads to bioprosthetic calcification in many patients. Epoxides are advantageous alternatives to glutaraldehyde, since they engender the biomaterial with better calcification resistance. The cross-linking features of an epoxy compound depend on its chemical structure and have not been fully studied so far.Aim. The study is aimed at comparing the effectiveness and molecular mechanisms of biomaterial treatment using diepoxide vs pentaepoxide compounds.Methods. We studied the stability of diepoxide and pentaepoxide in water and aqueous buffered solutions, as well as the amino acid composition, type of epoxide links with collagen matrix (infrared spectroscopy) and mechanical properties of bovine and porcine pericardia treated with 5% diepoxide, a mixture of 2% diepoxide and 1% pentaepoxide, and with alternating 5% diepoxide and 2% pentaepoxide treatments.Results. Diepoxide and pentaepoxide are both stable in aqueous buffer solutions (pH 7.4). Diepoxide provides high linkage density in bovine and porcine pericardia due to reactions with the amino groups of the OHLys, Lys, His, and Arg residues, and the hydroxyl groups of OHPro, Ser, and Tyr, while pentaepoxide reacts only with Met. Pentaepoxide enhances the strength and elasticity of the xenopericardium. Specimens consecutively treated with diepoxide and pentaepoxide were significantly thinner and featured the highest maximal tensile stress, maximal strain and elastic modulus in comparison with tissues treated with 5% diepoxide and diepoxide-pentaepoxide mixture.Conclusion. The alternating diepoxide-pentaepoxide combination for biomaterial cross-linking is a promising trend for bioprosthetic pericardium treatment..Received 26 September 2018. Revised 19 October 2018. Accepted 22 October 2018.Funding: The study was carried out with the support of a grant of the Russian Science Foundation No. 16-15-10315.Conflict of interest: Authors declare no conflict of interest.Author contributionsConception and study design: I.Yu. Zhuravleva, E.V. Karpova, L.A. OparinaData collection and analysis: I.Yu. Zhuravleva, E.V. Karpova, L.A. Oparina, N. Cabos, A.L. Ksenofontov, B.A. TrofimovStatistical data analysis: A.S. ZhuravlevaDrafting the article: I.Yu. Zhuravleva, E.V. Karpova, L.A. Oparina, A.S. ZhuravlevaCritical revision of the article: I.Yu. Zhuravleva, E.V. Karpova, L.A. Oparina, N.R. Nichay, A.V. Bogachev-Prokophiev, A.M. KaraskovFinal approval of the version to be published: I.Yu. Zhuravleva, E.V. Karpova, L.A. Oparina, N. Cabos, A.L. Ksenofontov, A.S. Zhuravleva, N.R. Nichay, A.V. Bogachev-Prokophiev, B.A. Trofimov, A.M. KaraskovORCID IDI.Yu. Zhuravleva, https://orcid.org/0000-0002-1935-4170E.V. Karpova, https://orcid.org/0000-0001-8803-4237L.A. Oparina, https://orcid.org/0000-0003-1286-2866N. Cabos, https://orcid.org/0000-0002-8178-7946A.L. Ksenofontov, https://orcid.org/0000-0003-1585-7907A.S. Zhuravleva, https://orcid.org/0000-0001-8427-1366N.R. Nichay, https://orcid.org/0000-0002-1763-9535A.V. Bogachev-Prokophiev, https://orcid.org/0000-0003-4625-4631B.A. Trofimov, http:// orcid.org/0000-0002-0430-3215A.M. Karaskov, https://orcid.org/0000-0001-8900-8524

Silver nanoparticles have been generated in aqueous buffer solution using a water-soluble silicon phthalocyanine sensitizer. Red light illumination (660 nm LED) was performed under aerobic conditions at ambient temperature in the presence of TEOA as a reductant. Structural characterization of the Ag nanoparticles formed was carried out by transmission electron microscopy (TEM). The resulting silver particles, depending on irradiation time and choice of procedure, were found to have a spheric shape and a narrow size distribution of 5-10 nm.

The electrochemical oxidation of 2-nitroso-1-naphthol (2N1N) in the absence and presence of some arylsulfinic acids in aqueous buffer/ethanol (30/70 v/v) mixtures has been studied. We were able to determine the pH-dependence behavior of 2N1N on the one hand and the changes on the voltammetric response of 2N1N that are caused by arylsulfinic acids, on the other hand. In addition, some new sulfonamide derivatives have been synthesized from the reaction of 2N1N with arylsulfinic acids, via a very simple and green method.

A new Schiff base fluorescent chemosensor (L1) and its reduced form (L2) have been designed and synthesized. Nanoparticles of L2 were also prepared by using a nanoprecipitation method. The nano-chemosensor of L2 shows very high selectivity and sensitivity towards Fe3+ and I− ions in aqueous buffer solution. L2 also shows selective detection and discrimination of Fe3+ and Fe2+ in an aqueous environment. The lowest detectable concentration of Fe3+ ions by L2 was found to be 68 nM.

The photophysics of an alkaloid harmaline in aqueous buffer solution and in the presence of cucurbit[7]uril have been studied. The photophysical properties of harmaline were modulated several folds due to addition of cucurbit[7]uril in the aqueous buffer solution. We have observed quenching of fluorescence intensity of harmaline with gradual addition of CB7. Isothermal titration calorimetry technique (ITC) was performed to get an idea about the thermodynamic parameters involved in the complexation process. From ITC, we observed that the complexation process was exothermic in nature and enthalpy driven process.

In this study, we report a highly stable fluorescent organic nano-chemosensor based on a N3O2-macrocyclic ligand. The chemosensor shows very high selectivity and sensitivity towards Fe3+ ions over other metal cations such as Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Al3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Ag+, Hg2+ and Pb2+ ions in aqueous buffer solution.

A biomimetic total synthesis of racemic homodimericin A was achieved in seven steps, including two cascade reactions. Aqueous buffer solutions are found to help both the oxidative dimerization cascade and the intramolecular Diels-Alder cascade. This synthetic sequence validates key steps in the biogenetic proposal of homodimericin A.

The one-step synthesis and characterization of a series of regioisomerically pure 5-carboxy-seminaphthofluoresceins (5-carboxy-SNAFLs) is reported. The optical properties were determined in aqueous buffer at around biological pH, and highly pH sensitive, large Stokes-shift fluorophores with emission in the deep-red to near-infrared region were identified.

A nuclear-localized fluorescent light-up probe, NucFP-NO2, was designed and synthesized that can detect CO selectively in an aqueous buffer (pH 7.4, 37 °C) through the CO-mediated transformation of...

25 páginas.- 2 figura.- 4 tablas.- 21 diagramas- 102 referencias, The application of biocatalysts to perform reductive/oxidative chemical processes has attracted great interest in recent years, due to their environmentally friendly conditions combined with high selectivities. In some circumstances, the aqueous buffer medium normally employed in biocatalytic procedures is not the best option to develop these processes, due to solubility and/or inhibition issues, requiring biocatalyzed redox procedures to circumvent these drawbacks, by developing novel green non-conventional media, including the use of biobased solvents, reactions conducted in neat conditions and the application of neoteric solvents such as deep eutectic solvents

We developed Pyr1-infliximab: a two-photon probe for TNF-α. Pyr1-infliximab showed absorption maxima at 280 and 438 nm and an emission maximum at 610 nm in an aqueous buffer and effective two-photon action cross-section values of (520-2830) × 10

Free cysteine residues react with QuatCy 1, by simply mixing the protein and dye in aqueous buffer at 37 °C. Another dye, MHI-148, can be used for a similar labelling protocol, but QuatCy reacts faster with all proteins studied, except albumin; it emerges here that this is because MHI-148 instantly forms of a non-covalent complex with albumin, but QuatCy does not. Labelling with QuatCy has advantages insofar as it is over five times brighter, and much more photostable, than MHI-148, and combination labelling with this dye pair will allow multiplexing in the near-IR region.

Histone deacetylases (HDACs) play a crucial role in numerous biological processes and therefore are targeted in anticancer research and in the field of epigenetics. Dithienylethenes (DTEs) and fulgimides were functionalized with hydroxamic acids, which is a known moiety binding to zinc dependent HDACs, to gain photoswitchable HDAC inhibitors. The new DTE based inhibitors showed moderate photochromic properties in polar solvents and the inhibitory activity changes up to a factor of four. The photochromic performance of the prepared fulgimide inhibitors was very good, even in aqueous buffer. They achieved a maximum three-fold difference in inhibitory activity. Docking experiments using the crystal structures of the tested enzymes gave a rationale for the observed moderate differences in the activities of the inhibitors.

The reaction of 2,2-bipyridine (bpy), NiCl2·6H2O and tetracyanoethylene (TCNE) affords a nickel complex, [Ni(bpy)3]⋅(PCPP)21 (PCPP: pentacyanopropenide, a compound derived from TCNE). Its structure has been characterized by physics-chemical and spectroscopic methods. This complex can electrocatalyze hydrogen generation both from acetic acid, with a turnover frequency (TOF) of 152.88 mol of H2 per mole of catalyst per hour an overpotential (OP) of 941.6 mV (in CH3CN), and from aqueous buffer (pH 7.0) with a TOF of 1464 mol of H2 per mole of catalyst per hour at an OP of 837.6 mV.

Ochratoxin A (OTA) represents one of the most widespread mycotoxins in agricultural commodities in the world and is considered a possible human carcinogen with its potent nephrotoxicity. OTA is stable under most food processing conditions; however, higher-temperature treatment may reduce OTA content in foods. Since OTA can be found in processed products destined for both human and animal consumption, factors affecting its stability or reduction during thermal processes were investigated here. The reduction of OTA was measured during various heating times (up to 60 min) at different temperatures (100, 125, 150, 175, and 200°C) in aqueous buffer solutions at different pHs (pH 4, 7, and 10). Quantification of OTA was carried out using high-performance liquid chromatography with fluorescence detection. The results showed that the rate and extent of OTA reduction were dependent on pH, processing time, and temperature; greater than 90% OTA reduction was achieved at 200°C for all treatments except pH 4. After processing under an alkaline condition (pH 10) at 100°C for 60 min, about 50% of the OTA was lost, while after 60 min under neutral and acidic conditions at 100°C, significant reductions of OTA were not shown.

A dual optical probe based on N -hydroxyethylindocyanine was prepared for the selective detection of cyanide in water. The probe exhibited a dramatic red-to-colorless optical change and a fluorescence on–off response in the visible region, displaying high selectivity toward cyanide over other various anions and Cys with a micromolar limit of detection (LOD = 2.0 μM) in an aqueous buffer. Furthermore, the probe underwent a reversible reaction with the probe-cyanide ion adduct in the presence of Hg(II), of which optical changes were easily detected by direct visualization.

The probe CT was synthesized and investigated as a novel label-free chemosensor for Ga(3+) detection in water. Probe CT showed remarkable selectivity and sensitivity for Ga(3+) in Tris-HCl aqueous buffer solution (pH7.0). The chemosensor responded rapidly to Ga(3+) with a 1:1 stoichiometry. Meanwhile, the unapparent changes of fluorescence lifetime decays suggest the turn-on process of probe CT by Ga(3+) which appears to be a static mechanism.

Homodimericin A is a fascinating fungal metabolite and a highly oxygenated cage-like polyketide. A practical total synthesis of homodimericin A has been achieved in 7 steps. The synthesis features a basic aqueous buffer promoted dimerization of quinone monomers, a thermal intramolecular Diels–Alder reaction and a carbonyl–ene cyclization cascade.

Common milk allergens, such as, β-lactoglobulin (β-LG), poses a major health concern for public, particularly in children. Thus, sensitive and selective methods for detection of common milk allergens are highly warranted. To the best of our knowledge, detection and quantification of β-lactoglobulin, a common milk allergen, by fluorescence based technique has not been reported till date. Herein, we present the first ever fluorescence based report for the selective detection and quantification of milk allergen, β-LG, using LDS-798 as a fluorogenic probe, which registers an exceptionally large fluorescence enhancement of ∼2900 fold in the far-red region upon binding with β-LG with LOD of ∼6.3 (±0.3) nM for β-LG in aqueous buffer solution and 0.67 (±0.04) μM in 5% bovine milk matrix respectively. High sensitivity and selectivity, fast response, high repeatability and reproducibility, easy operation, along with emission in the technologically advantageous far-red region make the fluorometric quantification of β-LG, using LDS-798 as a fluorogenic probe, far more advantageous than the other techniques, generally used for β-LG quantification. Importantly, we have demonstrated the applicability of this probe for quantification of β-LG in real milk samples which has been validated by an established method.

Because of the biological importance of CO, the development of effective probes for the detection of CO in living systems is of great significance. In particular, near-infrared (NIR) fluorescence probes with good water solubility and large Stokes shift are indispensable tools for CO detection in vivo. However, such tools are extremely scarce. Herein, a modified rhodol dye was used to develop a novel NIR fluorescent probe (Rh-NIR-CO) for selective and sensitive detection of CO using the Pd0-mediated Tsuji-Trost reaction. This probe shows good water solubility and rapid CO detecting ability in aqueous buffer at pH 7.4, accompanied by distinct colorimetric and turn-on NIR emission changes at 676 nm with a large Stokes shift (135 nm) and low detection limit (37 nM). Moreover, NIR fluorescence imaging of CO in living cells, zebrafish, and living mice was successfully applied with this probe. These excellent results highlighted Rh-NIR-CO as a promising new tool for in vitro and in vivo detection of CO.

The hydrolytic decomposition of four peptides containing S-aroylthiooximes (SATOs) with variable N-arylidene substituents was investigated in 10 aqueous buffer solutions at pH values ranging from 6.0 to 10.9. UV-Vis spectroscopy was employed to study the reaction kinetics, which revealed V-shaped pH-rate profiles for all peptides with a minimum near pH 8, suggesting a change from an acid-catalyzed to a base-activated reaction. Hammett plots showed positive ρ values above pH 8 and negative ρ values below pH 8, providing further evidence for a mechanism change. Based on these data, along with mass spectrometry evidence, we propose a specific acid catalysis under mildly acidic and neutral conditions and multiple base-promoted decomposition reactions under mildly basic conditions.

The sensitive imaging of amyloid-β (Aβ) peptides is important for the timely detection of neurodegenerative diseases, such as Alzheimer's disease (AD). Although clinically the diagnosis of AD relies on the use of radiolabeled imaging reagents, herein we report the simple construction of a "flat ensemble" formed between a quinoline-malononitrile AIEgen (EDS) and thin-layer molybdenum disulfide (2D MoS2 ) for the sensitive detection of Aβ by means of fluorescence-based techniques. Self-assembly between EDS and 2D MoS2 in aqueous buffer solution produces the flat ensemble, and the subsequent interaction of the material ensemble with oligomeric and aggregated Aβ peptides leads to up to 19-fold enhanced fluorescence of EDS. The ensemble is also applicable for staining Aβ aggregates in vivo.

The inhibitory efficacy of two substituted coumarin derivatives on the activity of neurodegenerative enzyme acetylcholinesterase (AChE) was assessed in aqueous buffer as well as in the presence of human serum albumin (HSA) and compared against standard cholinergic AD drug, Donepezil (DON). The experimental data revealed the inhibition to be of non-competitive type with both the systems showing substantial inhibitory activity on AChE. In fact, one of the tested compounds Chromenyl Coumarate (CC) was found to be better inhibitor (IC50 = 48.49 ± 5.6 nM) than the reference drug DON (IC50 = 74.13 ± 8.3 nM), unequivocally amplifying its importance. The structure of the compound was found to play a vital role in the inhibitory efficiency, validating previous Structure Activity Relationship (SAR) reviews for coumarin. The mechanism of inhibition remained impervious when the experimental medium was switched from aqueous buffer to HSA, albeit noticeable change in the inhibition potency of the compound 3, 3′- Methylene-bis (4-hydroxy coumarin) (MHC) (38%) and CC (35%). Both the coumarin derivatives were observed to bind to the peripheral anionic site (PAS) of AChE and also found to displace the fluorescence marker thioflavinT (ThT) from AChE binding pocket. All experimental observations were seconded by molecular docking and MD simulation results. The inferences drawn in this study form a foundation for further investigation on these compounds; magnifying the probability of their usage as AD drugs and re-emphasizes the significance of drug delivery media while considering the inhibition potencies of targeted drugs.

The inhibitive action of some azoles (1,2,4-triazole, 1,2,3-benzotriazole, 5-chlorobenzotriazole, and IFKhAN-92 corrosion inhibitor) on the corrosion of magnesium was investigated in aqueous buffer solutions and humid atmosphere. Increasing the hydrophobicity and decreasing the pKa of NH-acids enhance the protection of Mg by triazoles, that is why 5-chlorobenzotriazole and IFKhAN-92 – a mixture of substituted triazoles – are more efficient inhibitors. Small additions of dioctylphosphate increase the protection of Mg in aqueous solution by IFKhAN-92 inhibitor, and addition of trialkoxysilane to the mixed inhibitor allows one to enhance the protection of Mg in a humid atmosphere.

Self-assembled states of proteins render efficient promiscuous nucleophilic biocatalysis in MBH reaction in a green process. The His and Arg based catalophores in proteins operate in aqueous buffer at neutral pH and ambient temperature. Steady-state fluorimetric approaches reveal that lower order aggregates play a seminal role in the biocatalytic process.

A naphthalimide-based fluorescence light-up probe, FCP-Pd, has been designed and synthesized for selective detection and quantitation of creatinine in PBS buffer of pH 7.2 at 37 °C with a 'turn-on' response over a variety of interfering metal ions and/or anions and several biologically significant species. This probe is highly effective in estimating creatinine in human blood serum, which confirms the reliability and accuracy of this new system to be applied in clinical and toxicological analysis.

The interactions of L-phenylalanine and L-tryptophan with nicotinic acid and uracyl in an aqueous buffer solution at pH 7.35 were studied by IR spectroscopy. The contributions of various functional groups to the complexation of aromatic amino acids with heterocyclic ligands were determined from the IR spectra of the starting substances and their mixtures.

A novel Cu2+-specific colorimetric hydrazone sensor 1 was designed and developed. The color of 1 changes from colorless to pink on addition of 10.0 μM Cu2+ in aqueous buffer solution, which can be detected by the naked eye. The analytical detection limit for Cu2+ by the naked eye is as low as 2.0 μM. The stoichiometry for 1 and Cu2+ in complex is 2:1 in aqueous solution.

The impact of temperature, emulsifier, and protein type on the reactivity of malondialdehyde in oil-in-water emulsions was elucidated. Malondialdehyde recoveries in aqueous buffer, protein solutions, saturated oil, and fully hydrogenated coconut oil-in-water emulsions stabilized by whey proteins or Tween 20 at 4 or 40 °C were compared. At both temperatures, the reactivity of malondialdehyde in aqueous buffer was the same. In protein solutions, malondialdehyde concentrations were reduced further and its decrease was protein-dependent. Similar trends were found for emulsions. Surprisingly, malondialdehyde was very reactive in saturated oil because only 15% was recovered at 40 °C. However, the degradation in oil proved to be strongly temperature-dependent; at 4 °C, losses amounted to only 8%. This study revealed that malondialdehyde is a very reactive molecule, both in the presence and absence of proteins. Its use as a general oxidation marker should therefore be considered with care.

A metal-free method for fast and clean anilide formation from perfluoroaryl azide and thioacid is presented. The reaction proved highly efficient, displaying fast kinetics, high yield, and good chemoselectivity. The transformation was compatible with various solvents and tolerant to a wide variety of functional groups, and it showed high performance in polar protic/aprotic media, including aqueous buffer systems.

The effects of AOT reverse micelle system on the physicochemical properties of soy proteins were studied in this work. The aggregate size of soy proteins using AOT reverse micelle extraction was much larger than that using aqueous buffer extraction. After AOT reverse micelle treatment, the color differences of protein powder are significative, sulfhydryl and disulfide contents of soy proteins decreased, but surface hydrophobicity greatly increased. Compared to soy proteins from aqueous buffer extraction, the enthalpy, onset temperature and peak temperature of the proteins from AOT reverse micelle extraction increased. The textural analyses of the gels of the soy proteins presented higher hardness, adhesiveness, gumminess, chewiness and lower cohesiveness, springiness.