Nitrogen Doped Carbon Quantum Dots as Fluorescence "Turn-Off-On" Sensor for Detection of Fe Ions and Ascorbic Acid in Moringa oleifera and Citrus Lemon.

In recent year, the uses of carbon quantum dots (CQDs) have increased in many fields. Herein we report, synthesis of fluorescent nitrogen doped carbon quantum dots (N-CQDs) by simple and ecofriendly hydrothermal method. The as-synthesized N-CQDs were characterized by various techniques and the quantum yield was also calculated.

Inner-filter effect of nitrogen-doped carbon quantum dots-MnO nanotubes for smartphone-integrated dual-mode sensing of glutathione and captopril.

Nitrogen-doped carbon quantum dots (N-CQDs) exhibit unique fluorescence properties and are considered one of the best candidates for the development of fluorescence-based sensors for the detection of many analytes. In this work, a smartphone-assisted fluorescent sensor has been developed using N-CQDs and MnO nanotubes (MnO NTs) for the detection of glutathione (GSH) and captopril (CAP). N-CQDs were facilely synthesized the solvothermal method, where -phenylenediamine (-PD) and urea were used as nitrogen precursors.

Antibacterial Activity of CdTe/ZnS Quantum Dot-β Lactum Antibiotic Conjugates.

β-Lactum antibiotics are broad class of antibiotics which kills bacteria by inhibiting the formation of peptidoglycan that constitutes the bacterial cell wall. The resistance that develops in bacteria for antibiotics led the scientific world to think about the future aspects for modifying the way through which antibiotics are acted on the bacteria and become lethal for them. In this consequence, the potential of latest marketed antibiotics e.

β-Cyclodextrin Stabilized Nanoceria for Hydrolytic Cleavage of Paraoxon in Aqueous and Cationic Micellar Media.

Beta-cyclodextrin (β-CD) stabilized cerium oxide nanoparticles (β-CD@CeO NPs) were synthesized through a hydrothermal route. The electronic properties, surface functional group, surface composition, size, and morphologies of the as-synthesized β-CD@CeO NPs were characterized using UV-visible spectroscopy, FTIR analysis, high resolution X-ray photoelectron spectroscopy (HRXPS), high resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). The pH-dependent variation of the ζ-potential of β-CD@CeO NPs and the catalytic activity of the NPs for the hydrolysis of paraoxon were investigated.

Chemical fractionation of particulate-bound metal(loid)s to evaluate their bioavailability, sources and associated cancer risk in India.

Eleven potentially toxic metal(loid)s (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), proven source markers of mineral based coal-fired industrial emissions and vehicular exhausts, were analysed using the four steps sequential extraction method to evaluate metal(loid)s concentration, in total and fractions of bioavailable and non-bioavailable for fine (PM) and coarse (PM) particulate modes. A total of 26-day-wise samples with three replications (total number of samples = 78) were collected in January-December 2019 for each PM and PM at an urban-residential site in India. In both the coarse and fine particulate modes, Pb and Cr have respectively shown the highest and lowest total concentrations of the measured metal(loid)s, indicating the presence of coal-fired power plants and heavy vehicular activities near to study area.

Interaction of Folic Acid with Mn Doped CdTe/ZnS Quantum Dots: In Situ Detection of Folic Acid.

To utilize the nanomaterials as an effective carrier for the drug delivery applications, it is important to study the interaction between nanomaterials and drug or biomolecules. In this study GSH functionalized Mn-doped CdTe/ZnS QDs has been utilized as a model nanomaterial due to its high luminescence property. Folic acid (FA) gradually quenches the FL of GSH functionalized Mn - doped CdTe/ZnS QDs.

Carbon dot induces tolerance to arsenic by regulating arsenic uptake, reactive oxygen species detoxification and defense-related gene expression in Cicer arietinum L.

The scientific and technological applications of one of the nanomaterials viz.; carbon dot (C-dots), having extraordinary properties, is becoming an emerging and ongoing research area in recent times. In the present study, we have evaluated the effectiveness of C-dots in reducing arsenic (As) toxicity by analyzing physiological, biochemical and molecular parameters in Cicer arietinum L.

CdTe QD-based inhibition and reactivation assay of acetylcholinesterase for the detection of organophosphorus pesticides.

An enzyme immobilized glutathione (GSH)-capped CdTe quantum dot (QD)-based fluorescence assay has been developed for monitoring organophosphate pesticides. In principle, GSH-capped CdTe QDs exhibit higher sensitivity towards HO produced from the active enzymatic reaction of acetylcholinesterase (AChE) and choline oxidase (CHOx), which results in the fluorescence (FL) "turn-off" of the GSH-capped CdTe QDs. A "turn-on" FL of the CdTe QDs at 520 nm was recovered in the presence of organophosphate (OP).

Titanium nanoparticles attenuates arsenic toxicity by up-regulating expressions of defensive genes in Vigna radiata L.

Arsenic (As)-toxicity is recognized as one of the major environmental problems, affecting productivity of crops worldwide, thereby threatening sustainable agriculture and food security. Progression in nanotechnology and its impacts have brought up concerns about the application of engineered nanoparticles (NPs) in various sectors of the economy, including the field of agronomy. Among various NPs, there has been a rising amount of interest regarding the effects of titanium NPs (TiNPs) on plants growth and development, and their fate of abiotic stress tolerance.

Colorimetric and smartphone-integrated paper device for on-site determination of arsenic (III) using sucrose modified gold nanoparticles as a nanoprobe.

An optical colorimetric and smartphone-integrated paper device (SIPD) is demonstrated for determination of As (III) in water and soil samples using sucrose modified gold nanoparticles (AuNPs/Suc) as a nanoprobe. The mechanism for determination of As(III) is experimentally validated by performing UV-Vis, transmission electron microscope (TEM), Fourier transforms infra-red spectroscopy (FTIR) and dynamic light scattering (DLS) measurements. The density function theory (DFT) calculations using B3LYP with 6-311G (2d,2p) and LANL2DZ basis sets is used to theoretically prove the mechanism for determination of As(III).

A colorimetric nanoprobe based on enzyme-immobilized silver nanoparticles for the efficient detection of cholesterol.

A large number of cardiovascular diseases have recently become of serious concern throughout the world. Herein, we developed a colorimetric probe based on functionalized silver nanoparticles (AgNPs) for the efficient sensing of cholesterol, an important cardiovascular risk marker. A simple sodium borohydride reduction method was employed to synthesize the AgNPs.

Antidepressant drug-protein interactions studied by spectroscopic methods based on fluorescent carbon quantum dots.

A highly sensitive fluorescent carbon quantum dots (CDs) was designed to measure the interaction of antidepressant drugs and serum albumins (SA). In present investigation the interaction of bovine serum albumin (BSA) and human serum albumin (HSA) with antidepressant drugs viz. amitryptiline hydrochloride (AMT), chlorpromazine hydrochloride (CPZ) and desipramine hydrochloride (DSP) bioconjugated on CDs have been studied by different spectroscopic techniques i.

Interaction of synthesized nitrogen enriched graphene quantum dots with novel anti-Alzheimer's drugs: spectroscopic insights.

Alzheimer's disease (AD) is considered as one of widespread dementia with no approved diagnosis, cure or prevention. Currently, only symptomatic relief can be provided upon administration of anti-AD drugs generally belonging to a category of anticholinesterases and antagonists of N-methyl-D-aspartate (NMDA) receptors. In present investigation, a sensing platform has been designed for studying recently developed anti-AD drugs viz.

Self-aggregation of bio-surfactants within ionic liquid 1-ethyl-3-methylimidazolium bromide: A comparative study and potential application in antidepressants drug aggregation.

Aggregation behavior of bio-surfactants (BS) sodium cholate (NaC) and sodium deoxycholate (NaDC) within aqueous solution of ionic liquid (IL) 1-ethyl-3-methylimidazolium bromide [Emim][Br] has been investigated using surface tension, conductivity, steady state fluorescence, FT-IR and dynamic light scattering (DLS) techniques. Various interfacial and thermodynamic parameters are determined in the presence of different wt% of IL [Emim][Br]. Information regarding the local microenvironment and size of the aggregates is obtained from fluorescence and DLS, respectively.

Self-assembly of a short-chain ionic liquid within deep eutectic solvents.

Ionic liquids (ILs) and deep eutectic solvents (DESs) are receiving increased attention from both academic and industrial research due to their immense application potential. These designer solvents are environmentally friendly in nature with tunable physicochemical properties. In the present investigation, we have studied the aggregation behavior of a short-chain IL 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] within aqueous DESs using fluorescence, UV-vis, dynamic light scattering (DLS) and FT-IR spectroscopic techniques.

Antibacterial properties of amino acid functionalized silver nanoparticles decorated on graphene oxide sheets.

Graphene oxide (GO) sheets decorated with amino acid L-cysteine (L-cys) functionalized silver nanoparticles (GO-L-cys-Ag) was synthesized by AgNO, trisodium citrate, and NaBH. GO-L-cys-Ag nanocomposite was characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, which demonstrated that a diameter of L-cys-AgNPs compactly deposited on GO. Antibacterial activity tests of GO-L-cys-Ag nanocomposite were carried out using Escherichia coli MTCC 1687 and Staphylococcus aureus MTCC 3160 as model strains of Gram-negative and Gram-positive bacteria, respectively.

Surface plasmon resonance based spectrophotometric determination of medicinally important thiol compounds using unmodified silver nanoparticles.

The determination of thiol based biological molecules and drugs, such as cysteine (Cys) (I), α-lipoic acid (II), and sodium 2-sulfanylethane sulphonate (Mesna (III)) in human plasma are becoming progressively more important due to the growing body of knowledge about their essential role in numerous biological pathways. Herein we demonstrate a sensitive colorimetric sensor for the determination of medicinally important thiol drugs based on aggregation of the citrate capped silver nanoparticles (Ag NPs). This approach exploited the high affinity of thiols towards the Ag NPs surface which could tempt replacement of the citrate shell by the thiolate shell of target molecules, resulting in aggregation of the NPs through intermolecular electrostatic interaction or hydrogen-bonding.

Green Luminescent CdTe Quantum Dot Based Fluorescence Nano-Sensor for Sensitive Detection of Arsenic (III).

Arsenic (As) is a hazardous and ubiquitous element; hence the quantitative detection of arsenic in various kinds of environmental sample is an important issue. Herein, we reported L-cysteine capped CdTe Quantum dot based optical sensor for the fluorometric detection of arsenic (III) in real water sample. The method is based on the fluorescence quenching of QDs with the addition of arsenic solution that caused the reduction in fluorescence intensity due to strong interaction between As and L-cysteine to form As(Cys).

Synthesis and in-vitro reactivation screening of imidazolium aldoximes as reactivators of sarin and VX-inhibited human acetylcholinesterase (hAChE).

Post-treatment of organophosphate (OP) poisoning involves the application of oxime reactivator as an antidote. Structurally different oximes are widely studied to examine their kinetic and mechanistic behavior against OP-inhibited cholinesterase enzyme. A series of structurally related 1,3-disubstituted-2-[(hydroxyiminomethyl)alkyl]imidazolium halides (5a-5e, 9a-9c) were synthesized and further evaluated for their in-vitro reactivation ability to reactivate sarin- and VX-inhibited human acetylcholinesterase (hAChE).

Adsorption Kinetics and Binding Studies of Protein Quantum Dots Interaction: A Spectroscopic Approach.

Protein Quantum dots interaction is crucial to investigate for better understanding of the biological interactions of QDs. Here in, the model protein Bovine serum albumin (BSA) was used to evaluate the process of protein QDs interaction and adsorption on QDs surface. The modified Stern-Volmer quenching constant (Ka), number of binding sites (n) at different temperatures (298 308 and 318 K ± 1) and corresponding thermodynamic parameters (ΔG < 0, ΔH < 0, and ΔS > 0) were calculated.

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles.

Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient decontamination systems are required. Since the last few decades, the search for promising α-nucleophiles for straightforward and eco-friendly decontamination reactions using α-nucleophiles has been considerably boosted up. Among these, hydroxamic acids have been widely studied due to their potential α-nucleophilicity towards carbon and phosphorus based esters.

Physicochemical properties and supernucleophilicity of oxime-functionalized surfactants: hydrolytic catalysts toward dephosphorylation of di- and triphosphate esters.

Aggregation and kinetic studies have been performed to understand the hydrolytic potencies of the series of oxime-functionalized surfactants, viz., 3- hydroxyiminomethyl-1-alkylpyridinium bromide (alkyl = CnH2n+1, n = 10, 12, 14, 16, 18) in the cleavage of phosphate esters, p-nitrophenyl diphenyl phosphate (PNPDPP) and bis(2,4-dinitrophenyl) phosphate (BNDPP), in mixed micelles with cetylpyridinium bromide (CPB). Micellization and surface properties of mixed micelles functional surfactants with CPB were studied by conductivity and surface tension measurements.

Nucleophilic attack of salicylhydroxamate ion at C=O and P=O centers in cationic micellar media.

The reaction between the salicylhydroxamate anion (SHA(-)) and p-nitrophenyl benzoate (PNPB), tris(3-nitrophenyl)phosphate (TRIS), and bis(2,4-dinitrophenyl)phosphate (BDNPP) have been examined kinetically. The α-nucleophile, SHA(-), incorporated into cetyltrimethylammonium bromide (CTAB) micelles accelerates dephosphorylation of tris(3-nitrophenyl)phosphate (TRIS) over the pH range 6.7-11.

Enhanced nucleophilic reactivity of hydroxamate ions in some novel micellar systems for the cleavage of parathion.

The reactivity of three alpha-nucleophiles, i.e. N-phenylbenzohydroxamate, benzohydroxamate and salicylhydroxamate ions towards cleavage of p-nitrophenyldiethyl phosphorothioate (Parathion) is considerably enhanced in the presence of cationic surfactant, i.