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The discharge of organic dyes and hazardous heavy metals from diverse industries into the environment has become a serious problem. Herein, we report that N-myristoyltaurine capped copper nanoparticles (CuNPs) speeds up the decolorization of dye effluents in the presence of sodium borohydride (NaBH 4). The decolorization followed by UV–visible spectroscopy revealed that the reaction follows pseudo first-rate kinetics. All the tested dyes decolorized in less than 3 min. As a result of decolorization, the toxicity of the dye effluents decrease considerably, which was proved by seed germination assay. Further, the surface plasmon resonance property of the CuNPs was explored for selective and sensitive detection of hazardous mercury ions in sewage water (SW) and artificial cerbospinal fluid (aCSF). In the presence of Hg2+, galvanic displacement reactions promote the aggregation and the color change of CuNPs from wine red to grayish white. On the basis of colorimetric change, a minimum concentration of 15 μM of Hg2+ can be detected by the naked eye. The spectrophotometric detection method showed a detection limit of 0.1125 μM. Interference studies suggest that CuNPs is highly sensitive to Hg2+ ions. Recovery experiments proved that CuNPs quantitatively detect the spiked Hg2+ ions in tap water, SW and aCSF with an acceptable recovery range of 92 to 113%. Overall, the experimental outcomes suggest that the CuNPs could be deployed as a catalyst to decolorize dye effluents and as a colorimetric probe for mercury detection in wastewater. • Copper nanoparticles catalyst the decolorization of hazardous dyes. • Decolorization reaction was rapid and completed in less than 3 min. • Decolorization eliminates the toxicity of the dyes. • CuNPs serves as selective colorimetric sensor for hazardous mercury ions. [ABSTRACT FROM AUTHOR]

Abstract: Folding of polytopic transmembrane proteins involves interactions of individual transmembrane helices, and multiple TM helix–helix interactions need to be controlled and aligned to result in the final TM protein structure. While defined interaction motifs, such as the GxxxG motif, might be critically involved in transmembrane helix–helix interactions, the sequence context as well as lipid bilayer properties significantly modulate the strength of a sequence specific transmembrane helix–helix interaction. Structures of 11 transmembrane helix dimers have been described today, and the influence of the sequence context as well as of the detergent and lipid environment on a sequence specific dimerization is discussed in light of the available structural information. This article is part of a Special Issue entitled: Protein Folding in Membranes. [Copyright &y& Elsevier]

Many membrane proteins appear to be present and functional in higher-order oligomeric states. While few studies have analyzed the thermodynamic stability of a-helical transmembrane (TM) proteins under equilibrium conditions in the past, oligomerization of larger polytopic monomers has essentially not yet been studied However, it is vital to study the folding of oligomeric membrane proteins to improve our understanding of the general mechanisms and pathways of TM protein folding. To investigate the folding and stability of the aquaglyceroporin G1pF from Escherldiia coil, unfolding of the protein in mixed micelles was monitored by steady-state fluorescence and circular dichroism spectroscopy as well as by seminative sodium dodecyl sulfate-polyacryiainide gel electrophoresis analyses. On the basis of our results, it appears most likely that GIpE unfolds in a twostep process, involving the equilibrium of tetrasneric, dimeric, and monomeric GlpF species. A kinetic analysis also indicates an intermediate along the kinetic GIpF unfolding pathway, and thus, two phases are involved in GIpF unfolding. While three-state unfulding pathways and a dimeric folding intermediate are not uncommon for water-soluble proteins, a stable (un)folding intermediate with a decreased oligomeric stRicture has not been detected or reported for any a-helical membrane protein. [ABSTRACT FROM AUTHOR]

Interlinked aggregation induced emissive (AIE) fluorophores (triphenylamine (TPA) donor (D) and indanedione acceptor (A)) via non-conjugated spacers (1–3) showed concentration-dependent tunable fluorescence from blue to deep red/NIR in solution and deep red emission in the solid-state. 1–3 exhibited weak broad solid-state fluorescence covering the blue to deep red region (433 to 706 nm, ΦF = 2.3 to 5.3%). It is noted that the non-interlinked TPA-indanedione fluorophore was non-emissive in solution but showed strong solid-state fluorescence at 611 nm (ΦF = 17.7%). In contrast, 1–3 showed strong fluorescence in the solution state (ΦF = 0.001 to 0.09 compared to fluorescein). Importantly, 1–3 exhibited concentration-dependent tunable fluorescence from blue (457 nm) to deep red/NIR (720 nm) in CHCl3 due to varied aggregation of fluorophores. Dynamic light scattering (DLS) studies confirmed the molecular aggregation even at very low concentrations (10−7 M). The increasing concentration lowered the solubility and produced bigger aggregates with wide size distribution that caused tunable fluorescence. The deep red fluorescence of 1 was utilized for live-cell imaging applications using E. coli cells. Fluorescence microscopic images revealed clear red fluorescent E. coli cells with a rod morphology. Furthermore, the non-toxic nature of 1 was confirmed by in vitro as well as in vivo studies. Thus, deep red/NIR emissive fluorophores were achieved by interlinking two AIEgens using a non-conjugated spacer and utilized for live cell imaging. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and characterization of N-lauroyltryramine capped gold nanoparticles (NLTA-AuNPs) colorimetric sensor for selective and sensitive determination of Al3+ ions was reported. The color of NLTA-AuNPs changes visually from pink to purple from 6 μM Al3+, which is below the permissible level of Al3+ for drinking water (7.4 μM) described by world health orgainsation. The surface plasmon resonance (SPR) maximum of NLTA-AuNPs at 538 nm was selectively affected by the addtion of Al3+. Transmission electron microscopy revelaed that Al3+ ions induce the aggregation of NLTA-AuNPs. The mechanistic study suggests that Al3+ reduce the interparticle distance through chelation effect between NLTA and Al3+ ions. The absorbance ratio (A 670 /A 538) of NLTA-AuNPs follows a linear correlation with the Al3+ concentration range from 1 to 12 μM and the spectroscopy detection limit was as low as 1.15 μM. The interference study indicates that NLTA-AuNPs detects Al3+ ions even in the presence of environmentally dominant metal ions. The application of the proposed sensor was demonstrated through estimating Al3+ ions in ground water and sewage water with good recovery. The simplicity, rapid detection of Al3+ may allow the NLTA-AuNPs sensor beyond routine lab testing for on-site exploration. Image 1 • N-lauryltyramine capped gold nanoparticles was synthesized. • Al3+ ions was selectively detected with aid of color change in NLTA-AuNPs. • Mechanism of sensing is aggregation induced. • Naked eye detection limit is 6 μM, which is below WHO guidelines. [ABSTRACT FROM AUTHOR]

Water released by industries that generate coloured pollutants must be treated to safeguard the environment and ensure that the treated water is non-toxic. In this study, we demonstrate the utility of glycine-derived designer micelles, N-lauroyl-N-(pyridin-2-ylmethyl)glycine (PyN12G), as a capping agent to prepare black bismuth oxide nanoparticles (Bi2O3 NPs). The obtained Bi2O3 NPs were confirmed by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Transmission electron microscopy demonstrated that the Bi2O3 NPs are crystalline, with a quasi-spherical morphology and an average size of 42.3 nm, which are further corroborated by powder X-ray diffraction studies to be monoclinic. Fourier transform infrared spectra revealed that the surface of Bi2O3 NPs was stabilized by PyN12G and that the –COOH group of the micelles was involved in surface functionalization. The application of Bi2O3 NPs in environmental remediation was demonstrated by degrading a toxic dye, Congo red (CR). Bi2O3 NPs catalyze sodium borohydride-mediated CR degradation with an efficiency of 88.8% in 15 minutes and a rate constant of 1.92 × 10−3 s−1. Besides CR, Bi2O3 NPs catalyzed the degradation of methylene blue, bromophenol blue, Coomassie blue, crystal violet, and rhodamine B with efficiencies of 95%, 92%, 95%, 90%, and 86%, respectively. Gas chromatography-mass spectrometry analysis reveals that CR is degraded into smaller molecules. The disclosed dye degradation process eliminates the hazardous feature of the dye, which was proven by the seed germination assay. Furthermore, toxicology experiments revealed that Bi2O3 NPs do not affect bacterial growth or seed germination, proving that the NPs are non-toxic and safe to use as a chemocatalyst to eliminate toxic dyes without affecting the environment. [ABSTRACT FROM AUTHOR]

A simple green route was reported to prepare highly stable silver nanoparticles. The aqueous leaf extract of Durio zibethinus reduces Ag+ to Ag0 in the presence of natural sunlight. The capping and stabilization of dAgNPs by the phytoconstituents of Durio zibethinus was confirmed by FTIR. TEM confirms that the dAgNPs are spherical in shape with a size range between 10–25 nm. XRD pattern confirmed that the dAgNPs are arranged in the face-centred cubic structure. The catalytic activity of the dAgNPs was proved by sodium borohydride mediated reduction of nitro aromatic compounds and degradation hazardous organic dyes. The reaction kinetics was analysed by pseudo-first order equation. Regardless of the efficacy of degrading organic dyes, we showed by zebrafish mortality assay that the toxicity of the dye degraded water reduced drastically. Besides catalysis, the dAgNPs has the potential to selective colorimetric sensing of hazardous mercury ion in aqueous solution. [ABSTRACT FROM AUTHOR]

Herein, we report a simple and rapid method for the visual detection of sulfide ion in an aqueous environment with high sensitivity and specificity by using ciprofloxacin capped silver nanoparticles (Cip-AgNPs). The sensor system can be used to detect as low as 16 nM of S 2− in aqueous environment by only naked-eye and 0.112 nM of S 2− by absorption spectrophotometer. The visual detection limit of 16 nM is much lower than the maximum allowable level of S 2− (15 μM) in the drinking water defined by the world health organisation. The proposed sensor detects S 2− at a wide range of pH and also demonstrated to sense S 2− in tap water and river water, with good recovery. For portable use, we synthesized highly stable Cip-AgNPs on cotton and demonstrated good sensitivity against S 2− ion. As prepared Cip-AgNPs embedded cotton detects S 2− in an aqueous solution and S 2− in a gaseous state, indicating that our sensor meets the requirement for on-site detection of S 2− in the environment by only-naked eye. [ABSTRACT FROM AUTHOR]

Nanoparticles are being widely used as antibacterial agents with metal nanoparticles emerging as the most efficient antibacterial agents. There have been many studies which have reported the mechanism of antibacterial activity of nanoparticles on bacteria. In this review we aim to emphasize on all the possible mechanisms which are involved in the antibacterial activity of nanoparticles and also to understand their mode of action and role as bacterial enzyme inhibitor by comparing their antibacterial mechanism to that of antibiotics with enzyme inhibition as a major mechanism. With the emergence of widespread antibiotic resistance, nanoparticles offer a better alternative to our conventional arsenal of antibiotics. Once the biological safety of these nanoparticles is addressed, these nanoparticles can be of great medical importance in our fight against bacterial infections. [ABSTRACT FROM AUTHOR]

Herein, we report a laboratory convenient method for the preparation of blue color emitting fluorescent carbon dots (C-dots) in 60 min by boiling the alkaline solution of pectin. The C-dots derived from pectin detects selectively silver ion by forming silver nanoparticles (AgNPs) without any irradiation or heating or additional reducing agents. As prepared AgNPs appears yellow in color and showed the characteristic surface plasmon resonance maximum at 410 nm. Transmission electron microscopy (TEM) revealed crystalline, spherical AgNPs with size range from 10–15 nm. Cyclic voltammetry study revealed that the lower reduction potential of C-dots than that of silver ion favors the reduction of Ag + to Ag°. Electrochemical impedance spectroscopy showed the charge transfer value for the redox reaction of C-dots as 200 Ωcm 2 . In the presence of Ag + , C-dots fluorescence emission was turned from blue to cyan to green to colorless, accompanying the quenching and red shift in emission maximum at 450 nm. Interference study clearly showed that the C-dots have high preference for Ag + ion than the other interfering metal ions. The proposed sensor system selectively senses Ag + ion in water at micromolar concentration and also offers an easy procedure to prepare AgNPs in the presence of other interfering metal ions. [ABSTRACT FROM AUTHOR]

Aim: Polymicrobial biofilm encasing cross‐kingdom micro‐organisms are apparent in medicine, which imposes serious resistance to conventional antimicrobial treatment. The objective of the study was to explore Butea monosperma seed lectin (BMSL) conjugated antimicrobial lipid, 2‐((N‐[2‐hydroxyethyl]palmitamido)methyl)‐1‐methylpyridin‐1‐ium iodide (cN16E) to inhibit mixed‐species biofilm of uropathogenic Escherichia coli–Candida albicans. Methods and Results: Antimicrobial activity and antibiofilm of cN16E and cN16E‐BMSL conjugate (BcN16E) were analysed against single‐ and mixed microbial cultures. The minimum inhibitory concentration (MIC) indicates that the MIC of cN16E‐BMSL conjugate (BcN16E) against cohabiting UPEC‐C. albicans was eightfold lower than the cN16E. BcN16E affects membrane integrity to elicit antimicrobial activity. BcN16E inhibits the dual‐species biofilm even with 16 times lower MIC of cN16E. BcN16E impairs the biofilm‐associated virulence factors which include extracellular polysaccharides, cell surface hydrophobicity, swimming, swarming motilities, hyphal filamentous morphology, curli formation and haemolysin activity. As a proof of concept, we demonstrated BcN16E ability to inhibit dual‐species biofilm formation on a urinary catheter. Conclusion: The study revealed that the BcN16E is better than cN16E in impairing biofilm‐associated virulence factors and exerting antimicrobial activity. Significance and Impact of the Study: The findings emphasize that phytolectin has the potential to enhance the anti‐virulence strategies of antimicrobials against cross‐kingdom biofilm‐related infections. [ABSTRACT FROM AUTHOR]

Chromium is recognized as a serious environmental pollutant because of high toxicity and carcinogenic properties. In this paper, we have developed cadmium sulfide quantum dots (CdS QDs) based fluorescence sensor for sensitive and selective detection of chromium ions. CdS QDs were synthesized by wet chemical method using pectin biopolymer as capping agent and taurine as an antioxidant. The fluorescence emission intensity of CdS QDs at 450 nm was selectively quenched by chromium ions, whereas other cations and anions showed negligible changes. The fluorescence intensity of CdS QDs is linearly proportional to the chromium concentration from 0.016 to 0.260 μM with a detection limit of 16 × 10 −9 M. The proposed sensor recognizes chromium ion at a wide range of pH from 4 to 10. In addition, CdS QDs were also used to detect chromium ions in biological fluid, sewage water, pond water and tap water samples, with low interference. [ABSTRACT FROM AUTHOR]

Vulvovaginal candidiasis (VVC) is a most common infection caused by Candida species especially, Candida albicans. Herein, we report that phytoprotein based nano scaffolds mitigates the standard antifungal drug (fluconazole) resistant C. albicans. Copper sulfide nanoparticles (CuS NPs) and the phytolectin, jacalin functionalized copper sulfide nanoparticles (JCuS NPs) were evaluated against C. albicans cells. The minimum inhibitory concentration of JCuS NPs (0.1 µM) was tenfold lower than CuS NPs (1 µM). Kill curve assay showed that the NPs exhibit anticandidal activity in a time dependent manner. Standard antifungal drugs like Amphotericin B (AMP B) and Micafungin (MF) were evaluated individually against VVC causing Candida sp. and also combined with NPs to determine their synergistic effect. Interestingly, MF which belongs to echinocandins group of antifungals exhibhited synergistic activity and AMP B which belongs to polyenes group displayed an additive effect. Molecular level studies revealed that JCuS NPs in combination with micafungin inhibits the drug resistant efflux pump of C. albicans by down-regulating the efflux genes. The results revealed that JCuS NPs and its combination with standard drugs have a better anti-candidal effect, suggesting that the lectins has the potential to serve as a drug carrier by targeting the cell surface glycans of Candida. [ABSTRACT FROM AUTHOR]

The advances in nanomedicine demonstrate the anticancer properties of silver nanoparticles (AgNPs) and considered as an alternative to the available chemotherapeutic agents. Owing to the preferential interaction of Artocarpus integrifolia lectin (jacalin) with Gal β1-3 GalNAc α (a chemically well-defined tumor associated antigen), a study was undertaken to understand the interaction mechanism of AgNPs with jacalin in presence of specific sugar, galactose. Fluorescence spectroscopic analysis revealed that the AgNPs binding significantly quenched the intrinsic fluorescence of jacalin through a static quenching mechanism, and a non-radiative energy transfer occurred within the molecules. Association constants obtained from the interaction of different sugar-stabilized AgNPs with jacalin are in the order of 10 4 M −1 , this is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one AgNPs, and the stoichiometry was unaffected by the presence of the specific sugar, galactose. Hemagglutination assay shows that sugar stabilized AgNPs interacts to jacalin at a site that is different from the saccharide-binding site. Analysis of the FTIR spectra of jacalin indicates that the binding of AgNPs does not alter the secondary structure of jacalin. More importantly, AgNPs exists in nano form even after interacting with the lectin. These results suggest that the development of lectin–AgNPs conjugate would be possible for diagnosis and treatment of cancer. [ABSTRACT FROM AUTHOR]

Highlights: [•] In situ preparation of silver nanoparticles based on homologues series of amphiphilic N-acyl tyramines. [•] Size and shape of the AgNPs were not altered by varying the acyl chain length of NATA. [•] NATA-AgNPs show remarkable catalytic activity in the reduction of nitroaromatics. [•] Rate of the reduction reaction is directly related to the capping agent hydrophobicity. [Copyright &y& Elsevier]

Herein, we report the synthesis of aqueous soluble zinc selenide quantum dots (ZnSe QDs) in the presence of N -acetyl cysteine (NAC) and a small amount of dimethylformamide (DMF). The resultant QDs fluoresce blue with an emission maxima at 465 nm. The transmission electron microscopy images showed well-dispersed spherical particles with an average particle size of 4.9 nm. Energy dispersive X-ray measurement and X-ray photoelectron spectroscopy support that QDs are made from Zn2+ and Se2−. The quantum yield of ZnSe QDs was 9.7% compared to standard quinine sulfate. Time-resolved fluorescence spectroscopy analysis revealed three lifetime components, suggesting potential recombination excited states. The average lifetime of ZnSe QDs was 48.07 ns. Sensing studies showed the ZnSe QDs fluorescence was turned off by adding Pb2+ ions in less than 90 s. The Stern-Volmer analysis showed that the sensing is through a static quenching mechanism with a Stern-Volmer constant of 11.37 (±0.03) × 105 M−1. The detection limit of the sensor is 0.37 μM. The recovery tests show that ZnSe QDs are capable of detecting Pb2+ in a variety of fluids, including tap water, pond water, sewage water, and biomimetic fluids, including artificial urine, saliva, and cerebrospinal fluid, as well as natural juices like lemon, tomato, and sugarcane. Selectively Pb2+ turn-off ZnSe QDs fluorescence via static quenching. [Display omitted] • Prepared blue emitting ZnSe QDs in aqueous solution with small amount of DMF. • Pb2+ ions was selectively sense through rapid fluorescence quenching. • Detection limit is 0.37 μM, which is comparable to WHO guidelines. • ZnSe QDs detects quantitatively Pb2+ in real fluids irrespective of interfering ions. [ABSTRACT FROM AUTHOR]

The visible light promoted, oxidative coupling of phenylhydrazine hydrochloride with 2H‐indazole derivatives has been demonstrated to obtain 3‐arylated‐2H‐indazole derivatives using a catalytic amount of 4CzIPN (1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene) as a photocatalyst under aerobic conditions. A library of arylated indazole derivatives was prepared in the organo‐photocatalytic pathway in good yields under mild reaction conditions. The present strategy was applied to synthesis liver X receptor agonist 4‐(7‐methoxy‐2‐phenyl‐2H‐indazol‐3‐yl) benzonitrile (3). [ABSTRACT FROM AUTHOR]

The emergence of drug-resistant microorganisms and the failure of conventional antibiotics demand extensive research efforts to develop more effective antimicrobial therapies. A new series of cationic N-acylethanolamines was synthesized through introducing a (2-methylene-1-methylpyridinium iodide) moiety, and their antimicrobial activity was evaluated against Mycobacterium smegmatis. The minimum inhibitory concentration (MIC) of cNAEs follows a fourfold decrement when the N-acyl chain length increases by two methylene units. Inspiringly, the lowest MIC of 15.63 μM was observed with 2-((N-(2-hydroxyethyl)palmitamido)methyl)-1-methylpyridin-1-ium iodide, suggesting the necessity of a hydrophilic–lipophilic balance for better antimicrobial activity. cNAEs are unique, because they do not produce reactive oxygen species as most antibiotics do, but exert antimicrobial activity through loss of membrane integrity and membrane depolarization. Further, cNAEs and their combination with a standard drug, isoniazid, exhibit synergistic activity at lower concentrations (cN16E/INH – 3.91/1.95 μM) in comparison to the MIC of the individual drug. Strikingly, the combination showed a bactericidal effect through bacterial membrane disruption, ROS generation and membrane depolarization. Notably, a hemolytic study showed that cN16E is nontoxic to human red blood cells, even above 100 fold higher MIC. The result signifies that cN16E can be used as a potential drug against mycobacteria, as well as in combination with other antimycobacterial drugs. [ABSTRACT FROM AUTHOR]

• Halo-bridged Cu(II) complexes prepared using pyridine-pyrazole ligands (L1-L3). • Copper(II) complexes exhibited lipophilicity and nature of halogen ligand dependent, selective antimicrobial activity against Gram-positive bacteria. • Dimeric Cu(II) complexes show supramolecular structure facilitated by intermolecular C–H···Cl and C–H···N hydrogen bonding interactions. • Hirshfeld surface analysis further support the intermolecular H-bonding interactions. • Molecular docking studies support the antimicrobial activity of copper complexes. A series of five coordinated, doubly halo bridged Cu(II) complexes [Cu 2 (μ-X) 2 (Ln) 2 × 2 ] (X=Cl and Br; n = 1, 2 and 3), CuL1Cl, CuL1Br, CuL2Cl, CuL2Br, CuL3Cl and CuL3Br (where L1 = 2-((1H-pyrazol-1-yl)methyl)pyridine, L2 = 2-((3-methyl-1H-pyrazol-1-yl)methyl)pyridine, L3 = 2-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine) have been synthesized and structurally characterized using FT-IR and UV–Vis spectroscopy analysis. Moreover, CuL1Cl, CuL1Br and CuL3Cl structures have also been confirmed by single crystal X-ray structural analysis. Copper ion in CuL1Cl, CuL1Br and CuL3Cl displayed distorted squared pyramidal geometry and formed dimers via bridged μ‑chloro/μ‑bromo coordination in the crystal lattice. The intermolecular C–H···Cl hydrogen bonding interaction further connected the dimers of CuL1Cl and CuL3Cl with four neighboring dinuclear complex units. Copper complexes were evaluated for their antimicrobial activity against Gram-negative and Gram-positive bacteria. Interestingly, copper complexes exhibited selective antimicrobial activity against Gram-positive bacteria. Further the increasing ligand lipophilicity showed the increase of antibacterial activity of copper complexes. The lipophilicity of ligands was regulated by number of methyl substituents on the ligands. The chloro bridged copper complexes exhibited relatively higher antibacterial activity compared to the bromo bridged copper complexes. Thus, the present structure-activity of simple copper complexes might provide insight on the structural design of new antimicrobial agents based on coordination complexes. [ABSTRACT FROM AUTHOR]

Lead is highly toxic. The detection of lead in the environmental bodies is difficult, because it is colourless and odourless. Herein, we report the synthesis of gold nanoparticles (AuNPs) using the interdigitized vesicles formed by N-decanoyltromethamine (NDTM). AuNPs stabilized by NDTM was pink in colour with spherical shape and the size is 29 ± 7 nm. The optical property of the NDTM-AuNPs was explored for the first time to detect toxic chemical, Pb2+. The addition of toxic metal ion Pb2+ to NDTM-AuNPs rapidly (< 1 min) alters the colour from pink to violet due to aggregation, which was confirmed by particle size analyser and TEM. The aggregation induced colour changes were realized via broad spectra in UV–Vis spectroscopy. NDTM-AuNPs showed a selective and sensitive spectrophotometric signal with Pb2+ when compared with other metal ions. The colorimetric change as a function of Pb2+ concentration gave a linear response in the range of 0–30 μM (R 2 = 0.9942). The detection limit was found at 10 μM by naked eye and 0.35 μM by spectrophotometry. The proposed method was successfully applied for the determination of Pb2+ ions in tap water and sewage water. Moreover, as a proof of concept, the NDTM-AuNPs sensor system was applied for the detection of lead in commercial paints. The results of the quantitative estimation of lead in paints by NDTM-AuNPs colorimetric sensor were as good as the standard method, atomic absorption spectroscopy. Unlabelled Image • Synthesis of AuNPs using N -decanoyltromethamine as capping agent • AuNPs responses selectively to Pb2+ through colour change from pink to violet • No interference from 19 other common interfering metal ions • AuNPs sense Pb2+ ions in real water samples and paint [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Sunlight mediated synthesis of AuNPs using a triterpenoid glycoside, escin. • Escin-AuNPs improves the glucose uptake in L6 rat skeletal muscle cells. • Escin-AuNPs showed excellent free radical scavenging activity. Abstract Herein, a natural sunlight mediated synthesis of gold nanoparticles (AuNPs) using escin, a triterpenoid glycoside was reported for the first time. Transmission electron microscopy imaging revealed that the size of escin stabilized AuNPs falls within the range of 5–20 nm and their surface plasmon resonance maximum was observed at 530 nm. Escin-AuNPs was found to improve insulin-dependent glucose uptake in L6 rat skeletal muscle cells, which was further confirmed by estimating the stored glycogen content. Escin-AuNPs exhibited excellent free radical scavenging activity. Thus, escin-AuNPs may be considered as promising molecule to test against diabetic complications. [ABSTRACT FROM AUTHOR]

Abstract A simple single-stage method, based on refluxing edible carrot with aqueous trisodium phosphate (TSP) has been reported to synthesize blue color luminescent carbon dots (CDs). Transmission electron microscopy (TEM) image showed that CDs are almost spherical in shape and the size is around 3–8 nm. Fourier-transform infrared (FTIR) and 1H NMR spectroscopy study revealed that the carbohydrates present in the carrot undergone carbonization to produce luminescent CDs. Optimization study indicate that refluxing 5 g of carrot in 80 mM TSP aqueous solution for 120 min is adequate to produce highly luminescent blue CDs. The CDs produced are used as luminophore to image bacteria through fluorescence microscopy. CDs have membrane good permeability and minimum toxicity against Gram-negative and Gram-positive bacteria. The CDs capability for direct reduction of silver ions to elemental silver (Ag0) and gold ions to elemental gold (Au0) without additional reducing and stabilizing agent was demonstrated. The resulting Ag and Au nanoparticles have a size of 8–22 nm and 5–15 nm, respectively. The catalytic activity of nanoparticles in the hydrogenation reaction was investigated. The results suggest that the nanoparticles had high catalytic activity in the sodium borohydride mediated hydrogenation of nitroaromatic compounds. Graphical abstract Unlabelled Image Highlights • Easily adaptable procedure to synthesis carbon dots was reported. • CDs has good membrane permeability to label live cells. • CDs reduces silver and gold ions into nanoparticles. • Silver and gold nanoparticles exhibit good catalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designer surfactants with C8 to C18 chain length designed, synthesized & studied. • Relationship between product yield, surfactant hydrophobicity and CMC identified • Key Intra/Inter C C & C N bond forming reactions performed. Designer micellar medium was explored for the transformation of diverse anilines to the corresponding densely substituted biologically relevant skatole derivatives in an aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both C C and C N bond forming reactions in water. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the self assembling properties of taurolipids were used to prepare stable copper nanoparticles (CuNPs), and demonstrated the ability of CuNPs to eradicate the biofilms formed by waterborne pathogens. The synthesized CuNPs display wine red color and exhibited surface plasmon resonance with a maximum at 590 nm. Transmission electron microscopy showed that the CuNPs are well-dispersed with spherical morphology and the size range between 5 and 12 nm. The powder X-ray diffraction study revealed that the CuNPs was free from copper oxide impurities and crystalline with the face centered cubic structure. The CuNPs exhibited excellent anti-biofilm activity against water borne pathogens such as Escherichia coli , Pseudomonas aeruginosa , Salmonella typhi , and Shigella flexneri. Light microscopy and scanning electron microscopy (SEM) study revealed that CuNPs eliminates the mature biofilm at the minimum biofilm eradication concentration of 12.5 μM. The antimicrobial activity of the CuNPs was observed at the minimum inhibitory concentration of 25 μM, indicating the reported CuNPs exhibit true anti-biofilm effect. Fluorescence microscopy and SEM study proved that CuNPs kills the bacteria through membrane damage. The possibility to use CuNPs in cleaning biofilm formed on storage containers was demonstrated through removing the mature biofilm formed on a glass pipe. Graphical abstract Image 1 Highlights • N -myristoyltaurine is used to stabilize copper nanoparticles. • CuNPs exhibit true anti-biofilm effect at 12.5 μM. • CuNPs disintegrate mature biofilm in 30 min. • CuNPs display antimicrobial effect from 25 μM. [ABSTRACT FROM AUTHOR]

Heavy metals released by anthropogenic activities are extremely toxic to animals and plants due to their bioaccumulative and persistent environmental presence. In the current study, silver nanoparticles (AgNPs) were synthesized utilizing eco-friendly processes, and their potential in colorimetric Hg2+ ion sensing in environmental samples was examined. An aqueous extract of Hemidesmus indicus root (Sarsaparilla Root, ISR) rapidly converts silver ions into AgNPs within 5 min of exposure to sunlight. Transmission electron microscopy confirms that ISR-AgNPs are spherical, ranging from 15 to 35 nm. Fourier-transform infrared spectroscopy revealed phytomolecules stabilized the NPs with hydroxyl and carbonyl substituents. The ISR-AgNPs detect Hg2+ ions by a colour change that can be seen with the naked eye within 1 min. The probe is interference-free and detects the presence of Hg2+ ions in sewage water. A method for fabricating ISR-AgNPs onto paper was disclosed, and this portable ISR-AgNPs embedded paper device was found to be good at sensing mercury present in the water. The findings show that environmentally friendly synthesized AgNPs can contribute to developing onsite colorimetric sensors. [Display omitted] • Rapid silver nanoparticles synthesis using sunlight and Hemidesmus indicus root extract. • Phytochemicals stabilize the AgNPs. • Paper fabricated with AgNPs sense mercury with good selectivity. • AgNPs disrupt bacterial membranes and kill them. [ABSTRACT FROM AUTHOR]

The organic transformations in water are considered a safe, non-toxic, economical, and eco-friendly alternative. A new series of amphiphile, N -acyl- N -(pyridin-2-ylmethyl)glycine (PyNAG) with variable hydrophobicity was successfully synthesized from glycine. The self-assembly properties were characterized by critical micellar concentration (CMC), aggregation number (N agg), and diameter (D H). The PyNAG with N - stearoyl moiety showed lower CMC, higher N agg , and larger D H compared to PyNAG with N - lauryl moiety. Molecular dynamics simulation reveals that the micelle structure is compact and non-bonded energy contribution arises from electrostatic, and van der Walls forces contribute to perfect packing and micelle formation. The ability of the PyNAG micelles to execute important organic transformations in water was demonstrated through synthesizing chromenoquinoline via the Povarov reaction. Micelles with varying diameters were used to conduct the Povarov reaction in order to better understand the functions of the hydrophobicity core of the micellar environment in organic reactions. The results reveal that the Povarov reaction produces a good yield in N -stearoyl- N -(pyridin-2-ylmethyl)glycine (PyN18G) micelles, better than organic solvent and commercial surfactant. Moreover, a linear correlation between the yield and the hydrophobicity of the PyNAG was observed. The findings demonstrate that the micellar interior significantly affects the reactivity of the substrate, which should be taken into consideration while creating new media for metal-catalyzed green synthesis. [Display omitted] • Reported micelle formation from pyridine tethered N-acyl glycine. • Electrostatic and van der Walls forces contributes for micelle packing. • Micelles serves as a medium for Povarov reaction on water. • Micelle hydrophobicity play significant role in chromenoquinoline synthesis. [ABSTRACT FROM AUTHOR]

A new pyrene-appended polypyridine ligand, wherein the 1,10-phenanthroline (phen) and the photoactive pyrene chromophore is connected via a C N bond; N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine (ppym) and its complex [Ru(phen) 2 ( ppym ) ] 2+ was synthesized. Characterization of the ligand and the complex was investigated through elemental analysis, UV-vis, IR, 1 H NMR, MALDI-TOF mass and cyclic voltammetry techniques. The change in dipole moment of the ground and the excited state of the chromophores with the different solvent polarity was examined. The dual emission (Excimer) characteristics observed for ligand ppym has been probed by detailed photophysical studies involving variable concentration, excitation wavelength and solvent experiments and also transition metal ion induced quenching data. 3 MLCT emission was observed for [Ru(phen) 2 ( ppym ) ] 2+ . Absorption, emission, thermal melting and viscosity studies reveal that [Ru(phen) 2 ( ppym ) ] 2+ bind to CT DNA avidly and that ruthenium-bound ppym intercalate inside the base sets of the duplex. Also, the DNA photonicking activity (pBR 322 DNA, λ exc  = 450 nm) of [Ru(phen) 2 ( ppym ) ] 2+ is almost four times higher than [Ru(phen) 3 ] 2+ . Through inhibitor studies, we found that reactive oxygen species play a major role in the photo cleavage of [Ru(phen) 2 ( ppym ) ] 2+ . The cytotoxicity of the complex was tested in Human cancer cell line (ZR-75-30) by MTT assay. In addition, modeling studies scaffold the intercalative binding to the d(CGCAATTGCG) 2 sequence. [ABSTRACT FROM AUTHOR]

In any therapeutic modality the usage of drug in high doses often leads to serious side-effects. Herein, we demonstrated a method to enhance the antibacterial efficacy of CuS NPs at lower concentration through interacting with jackfruit seed lectin, jacalin. Fluorescence quenching studies revealed that jacalin form complex with CuS NPs and the association constant was 1.91 × 10 4  M −1 . Upon complex with jacalin, the bacterial minimum inhibitory concentration (MIC) of CuS NPs drastically decreases from 12.5 μM to 0.78 μM. The addition of jacalin specific sugar, galactose to jacalin-CuS NPs complex (JCuS NPs) reverses the MIC from 0.78 μM to 25 μM. Mechanistic study suggests that JCuS NPs kills bacteria in part by reactive oxygen species and membrane damage, but galactose prevents the action of JCuS NPs at 0.78 μM. JCuS NPs successfully reduce (14 fold) A. hydrophila colonization in an infected zerbra fish and rescue them completely from the infection, but galJCuS NPs and CuS NPs were ineffective at 0.78 μM. Collectively, our studies demonstrates that the enhance antibacterial activity of JCuS NPs is likely due to the interaction between the galactose binding site of jacalin and the bacterial strains, as a result NPs are targeted and delivered sufficiently. [ABSTRACT FROM AUTHOR]

N -acyltaurines (NATs) are biologically active amphiphilic lipids. They come under the group of compounds known as N -acyl amino acids. NATs were first detected in the brain and other tissues in mice lacking the enzyme fatty acid amide hydrolase FAAH (−/−). N -arachidonoyltaurine (20:4 NAT) acts as an excellent ligand for the subset of transient receptor potential (TRP) channels, especially vanilloid type channels TRPV1 and TRPV4. Also, hydrophobic and hydrophilic regions of NATs enable them to interact with membrane lipids. Here, we have investigated the interaction of NATs, N -myristoyltaurine (NMT), and N -palmitoyltaurine (NPT) with their corresponding diacyl phosphatidylcholines (PCs), dimyristoylphosphatidylcholine (DMPC), and dipalmitoylphosphatidylchoine (DPPC). The miscibility and phase behavior of the hydrated binary mixtures have been investigated by differential scanning calorimetry (DSC). Studies on the interaction of NMT/NPT with DMPC/DPPC revealed that the two amphiphiles mix well up to 50 mol% of NAT and phase separation is observed at higher contents of the NAT. The phase transition of the equimolar mixtures of NAT:PC (50:50) studied by fluorescence, also supported the DSC results. PXRD and FTIR analysis show that the NAT:PC equimolar mixture (50:50) forms different supramolecular structures when compared to that of individual NATs and PCs. From transmission electron microscopic studies it is observed that the equimolar mixtures of NMT and NPT with their corresponding diacylphosphatidylcholines (50:50, mol/mol) forms unilamellar vesicles whose diameter range between 30 and 50 nm. [Display omitted] • N -acyltaurines (NATs) are structurally related to endocannabinoids, that contain taurine moiety as their polar head group • In DSC Studies of NATs with PCs, two lipids mix well up to 50 mol% and phase separation is noticed at higher NAT content • PXRD and FTIR analysis revealed that the supramolecular structure of equimolar mixtures of NATs and PCs are altered • TEM result shows that the equimolar mixtures of NATs with PCs (50:50, mol/mol) form spherical unilamellar vesicles • These interesting properties of NATs hint at their potential in drug delivery and drug formulation applications. [ABSTRACT FROM AUTHOR]

Herein, we report a facile method to synthesis copper nanoparticles (CuNPs) using fatty acid amide, N -lauryltyramine (NLTA) and hydrazine as capping and reducing agent, respectively. As prepared CuNPs aqueous solution appears brown in color and shows intense surface plasmon resonance (SPR) band at 580 nm. In presence of amino acid, cysteine (Cys), the brown CuNPs solution turned to olive green with concomitant change in SPR maximum, while other amino acids show negligible change in the color and UV–vis spectra of CuNPs. The spectrophotometry detection limit of the proposed sensor is 0.10 μM, whereas naked eye limit of detection was estimated to 20 μM. FTIR studies revealed that Cys forms layer on the surface of the CuNPs, which was further supported by electrochemical studies. The proposed method has been successfully validated by detecting Cys in blood plasma and tap water samples. [ABSTRACT FROM AUTHOR]

In this paper, the application of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) synthesized using a biomimetic lipid, N-myristoyltaurine (N14T) was evaluated in common fields. The catalytic effectiveness of AgNPs and AuNPs was studied in the popular nanocatalyst reaction, nitroaromatic reduction, and dye degradation. Both NPs display catalytic activity in the nitroaromatic compound and organic dyes reduction reaction involving sodium borohydride and the rate constant is estimated as 10−3 s−1. Strikingly, the reaction initiation time (t 0) and completion time (t c) differ significantly between AgNPs and AuNPs. Analyzing the reaction kinetic profile revealed that the reaction carried out with AuNPs showed a shorter t 0 and t c , suggesting a better catalyst than AgNPs. In addition, the efficiency of the NPs was examined in Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli , Pseudomonas aeruginosa). In difference to the catalytic study, AuNPs display poor antibacterial activity. Whereas AgNPs kill the tested bacteria at 250 μM via disturbing bacterial membrane integrity and produce excess reactive oxygen species. The toxicology study carried out with zebrafish animal model reveals that both AgNPs and AuNPs are non-toxic. The findings suggest that each nanomaterial possesses unique physicochemical properties irrespective of stabilization with the same molecules. •Both NPs display catalytic activity in the nitroaromatic compound and organic dyes reduction •the reaction initiation time (t0) and completion time (tc) differ significantly between AgNPs and AuNPs. • the reaction carried out with AuNPs showed a shorter t0 and tc, suggesting a better catalyst than AgNPs. •The toxicology study carried out with zebrafish animal model reveals that both AgNPs and AuNPs are non-toxic. [ABSTRACT FROM AUTHOR]

The rising threat to antibiotic armamentarium demand innovative methods to use standard antibiotics against multidrug-resistant (MDR) pathogens. Herein, we demonstrated phytolectin-cationic lipid complex have the ability to renew the ciprofloxacin (CIP) activity against MDR uropathogenic Escherichia coli (R4UPEC). The minimum inhibitory concentrations (MIC) obtained for CIP against R4UPEC studied were very high (MIC = 1000 µM) which may not be suitable for clinical testing. Strikingly, CIP in combination with Butea monosperma seed lectin (BMSL) and cationic lipid, 2-((N-(2-hydroxyethyl)palmitamido)methyl)− 1-methylpyridin-1-ium iodide (cN16E) showed 64-fold lower MIC (15.63 µM). Checkerboard assay revealed that the BMSL-cN16E (BcN16E) complex and CIP work synergistically against R4UPEC. The complex, BcN16E-CIP exerts antimicrobial activity through outer membrane permeabilization, inner membrane disruption, proton motive force dissipation and enhancing the generation of reactive oxygen species. The therapeutic efficacy evaluated in a zebrafish, intramuscular infection model using R4UPEC, the BcN16E-CIP reduce the bacterial load and decrease neutrophil infiltration in muscles and low down the liver cell necrosis. The results demonstrate significantly lower MIC for CIP when complex with BcN16E and showed exceptional in vivo efficacy against infectious MDR bacteria. [Display omitted] • Phytolectin-lipid conjugates enhance ciprofloxacin activity. • Antimicrobial mechanism attributed to modulation in outer and inner membrane. • The conjugate inhibits the efflux pumps. • Treatment with conjugate rescue the multidrug-resistant infected zebrafish. [ABSTRACT FROM AUTHOR]

6-azauridine (AzU), a pyrimidine nucleoside antimetabolite, was known to inhibit the growth of microorganism and transplantable tumors. The binding affinity of AzU to blood serum proteins might influence the effectiveness of the drug. Herein, we investigated the interaction of AzU with bovine serum albumin (BSA) under near physiological conditions. Fluorescence spectroscopy analysis revealed that AzU strongly quenched the intrinsic fluorescence of BSA through a static quenching procedure, and a non-radiation energy transfer occurred within the molecules. Thermodynamic parameter determined from the temperature dependent binding constant suggests that the interaction of AzU with BSA is governed by enthalpic forces with a negative entropic contribution. Displacement studies and protein/drug docking studies suggest that AzU binds non-competitively to both sub-domain IIA and sub-domain IIIA of BSA. The obtained results reveal that AzU can bind to BSA with considerable affinity even in the presence of coexisting drug and can be used along with other drugs. [ABSTRACT FROM AUTHOR]

Owing to the use of quantum dots in biological labeling, and the specific interaction of lectins with tumor cells, studies on lectin–QDs interaction are of potential interest. Herein, we report a facile method to prepare zinc sulfide quantum dots (ZnS QDs) using pectin as a capping agent and studied their interaction with snake gourd seed lectin (SGSL) by fluorescence spectroscopy. The QDs were characterized by X-ray diffraction, high-resolution transmission electron microscopy, UV–Vis absorption and fluorescence spectroscopy. The thermodynamic forces governing the interaction between ZnS-QDs and SGSL have been delineated from the temperature dependent association constant. These results suggest that the binding between ZnS QDs and SGSL is governed by enthalpic forces with negative entropic contribution. The red shift of synchronous fluorescence spectra showed that the microenvironment around the tryptophan residues of SGSL was perturbed by ZnS-QDs. The obtained results suggest that the development of optical bioimaging agents by using the conjugated lectin–QDs would be possible to diagnose cancerous tissues. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rapid synthesis of biogenic gold nanoparticles based of S. brachiata plant extract. [•] SbAuNPs act as an efficient catalysis for reduction of 4-nitrophenol to 4-aminophenol. [•] SbAuNPs catalysis NaBH4 mediated reduction of methylene blue to leucomethylene blue. [•] SbAuNPs exhibit bactericidal property against pathogenic bacteria. [•] SbAuNPs in combination with ofloxacin shows superior bactericidal property. [Copyright &y& Elsevier]

Highlights: [•] Aqueous extract of the aerial parts of Salicornia brachiata are efficient in producing silver nanoparticles. [•] SbAgNPs shows remarkable catalytic activity in the reduction of 4-nitro phenol to 4-amino phenol. [•] SbAgNPs, minimum inhibitory concentration is lower than the control antibiotic, ciprofloxacin. [•] SbAgNPs exhibit excellent free radical scavenging activity. [Copyright &y& Elsevier]

[Display omitted] • Reported the synthesis of cationic lipid capped copper sulfide nanoparticles. • NPs kill Carbapenem-Resistant Acinetobacter baumannii. • NPs exhibit two-fold higher efficiency than the antimicrobial lipid. • Bactericidal action via membrane damage and excess ROS production. Herein, cationic antimicrobial lipid, [2-((N-(2-hydroxyethyl)palmitamido)methyl)-1-methylpyridin-1-ium iodide], (cN16E) was reported for the first time as stabilizing agent in the preparation of copper sulfide nanoparticles (cN16E-CuS). X-ray photoelectron spectroscopy confirmed the formation of cN16E-CuS, and FTIR analysis revealed that the NPs were stabilized by cN16E. Transmission electron microscopy imaging showed that the NPs are in the size range from 6 to 8 nm. The cN16E-CuS exhibit excellent antimicrobial activity against Carbapenem-Resistant Acinetobacter baumannii with a MIC of 62.5 µM, which is two-fold lower than the MIC of pure cN16E. Mechanistic study showed that pure cN16E damages bacterial membranes, whereas cN16E-CuS produces additional effect through producing excess reactive oxygen species and exhibit superior antimicrobial activity at lower concentration. [ABSTRACT FROM AUTHOR]

γ-Secretase is critically involved in the Notch pathway and in Alzheimer's disease. The four subunits of γ-secretase assemble in the endoplasmic reticulum (ER) and unassembled subunits are retained/retrieved to the ER by specific signals. We here describe a novel ER-retention/retrieval signal in the transmembrane domain (TMD) 4 of presenilin 1, a subunit of γ-secretase. TMD4 also is essential for complex formation, conferring a dual role for this domain. Likewise, TMD1 of Pen2 is bifunctional as well. It carries an ER-retention/retrieval signal and is important for complex assembly by binding to TMD4. The two TMDs directly interact with each other and mask their respective ER-retention/retrieval signals, allowing surface transport of reporter proteins. Our data suggest a model how assembly of Pen2 into the nascent γ-secretase complex could mask TMD-based ER-retention/retrieval signals to allow plasma membrane transport of fully assembled γ-secretase. [ABSTRACT FROM AUTHOR]

Functionalizing the nanoparticles to target the bacteria surface is an effective approach to curb drug resistance pathogens. The present study describes the synthesis of N-myristoyltaurine capped silver nanoparticles (AgNPs) and functionalization of AgNPs with jacalin (JAgNPs), a lectin from the seeds of Artocarpus integrifolia. JAgNPs has fourfold lower minimum inhibitory concentration than AgNPs and kills the S. aureus in less than 30 min through inducing oxidative stress and membrane damage. JAgNPs (31.25 µM) was found to have excellent biofilm inhibitory activity at lower concentration than AgNPs (62.5 µM). This was judged by crystal violet assay, light microscopy imaging and confocal laser scanning microscopy (CLSM) method. CLSM analysis reveals that JAgNPs is highly effective as compared to AgNPs in reducing the bio-volume and average biofilm thickness to 18.3 ± 2.5 µm3/µm2 and 14.0 ± 2.6 µm, respectively. Scanning electron microscopy (SEM) study reveals that JAgNPs prevents the colony formation and inhibited exopolysaccharide synthesis, thereby reducing the formation of biofilm. At minimum biofilm inhibitory concentrations, SEM and double staining technique using CLSM provides evidence that cells are intact and live, suggesting that NPs exhibit true biofilm activity. The findings indicate that jacalin functionalization may offer a unique way to use nanosilver at lower concentrations for treating infection associated with S. aureus biofilm. [Display omitted] • Jacalin functionalized AgNPs kills S. aureus in less than 30 min. • NPs exert antibacterial activity through inducing oxidative stress and membrane damage. • Jacalin-AgNPs exhibit antibiofilm activity at 0.5X MIC. • NPs inhibits exopolysaccharide biosynthesis. [ABSTRACT FROM AUTHOR]

Copper nanoparticles are synthesized at ambient conditions from aqueous suspensions of CuCl2, pectin as a capping agent, N2H4 as a mild reducing agent, and NH3 solution (open air, 3 h). [ABSTRACT FROM AUTHOR]