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Herein, a facile, green and eco‐friendly approach has been applied for the synthesis of fluorescent green‐blue carbon dots (GB‐CDs) through the one‐pot hydrothermal treatment of Artocarpus lakoocha seeds for the first time and entirely characterized via a variety of instrumental techniques like fluorescent spectroscopy, Transmission Electron Microscopy (TEM), X‐Ray Photoelectron Spectra (XPS), X‐Ray diffraction (XRD) and Fourier Transform Infra‐red (FTIR) analysis. The as‐prepared GB‐CDs displayed high fluorescent quantum yield (QY) up to 38.5% and high photostability based on which GB‐CDs were successfully applied as a sensitive nanoprobe for the detection of Fe3+ ion. The sensing of Fe3+ shows a linear range from 2 to 6 μM and the limit of detection was found to be 0.62 μM. The sensing of Fe3+ was further investigated in the bona fide sample like river water and human blood serum. In addition, to explore the potential application, MTT assay was carried out on SH‐SY5Y neuroblastoma cells. The results showed negligible cytotoxicity as well as high cell viability, which revealed that GB‐CDs could be utilized as a fluorescent probe in living cells. [ABSTRACT FROM AUTHOR]

A fluorescent gel has been prepared by deprotonation of non-fluorescent adipic acid derived ligand (H4AL) with LiOH followed by coordination with Cd(II) in DMF. The mechanism of gelation is examined by IR, 1H NMR, UV-vis, Job's plot, PXRD, SEM and TEM. Chelation enhanced fluorescence by Cd(II) has been established by fluorescence experiments. In addition to synthesis and characterization of this gel, we compared the gel properties by varying the core of the ligand using citric (H6CL) acid derivatives. [ABSTRACT FROM AUTHOR]

Abstract Herein, we were synthesized fluorescent carbon quantum dots via facile one-step hydrothermal treatment of mustard seeds (M-CQDs). It showed excellent optical property with fluorescent quantum yield 4.6%. The as-prepared M-CQDs exhibited peroxidase-like mimetic activity and catalyzed the oxidation of chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue color reaction mixture with the prominent peak at 652 nm. Furthermore, the peroxidase-like catalytic performance of M-CQDs followed the steady-state kinetics behavior and exhibited similar catalytic activity as that of natural enzyme Horseradish peroxidase (HRP). In addition to this, the double reciprocal plot showed a parallel line which suggested the occurrence of Ping-Pong type of mechanism. The H 2 O 2 dependent oxidation of TMB was helpful for the colorimetric detection of H 2 O 2 in the linear range of 0.02–0.20 mM with the limit of detection (LOD) of 0.015 mM. Interestingly, the oxidized TMB (ox-TMB) was further reduced to native TMB by the reducing agent ascorbic acid. Hence M-CQDs showed its potential towards the selective and sensitive detection of ascorbic acid in the linear range of 10–70 μM having a correlation coefficient of 0.998 with LOD of 3.26 μM. The practical feasibility of the proposed detection method of AA was also investigated in common fresh fruits. Graphical abstract Image 1 Highlights • Green precursor and ecofriendly route were applied for the synthesis of fluorescent carbon quantum dots. • The synthesized M-CQDs showed peroxidase like activity to oxidize the TMB in presence of H 2 O 2 via ping- pong mechanism. • The H 2 O 2 dependent oxidation of TMB by M-CQDs act as sensor for detection of H 2 O 2 with lower limit up to 0.015 mM. • Interestingly, ox-TMB further reduced to native form by ascorbic acid with good selectivity and sensitivity. • The ox-TMB based sensing showed excellent practical feasibility for the detection of AA in edible fruits viz. real sample. [ABSTRACT FROM AUTHOR]

Herein, we report a green synthetic approach for the synthesis of water-soluble fluorescent CQDs via a simple one-step hydrothermal treatment using Tamarindus indica leaves for the first time. The prepared CQDs show an excitation-dependent behavior in the range from 260 to 400 nm with a high QY of approximately 46.6%. Further, the prepared CQDs serve as a very sensitive nanoprobe for the turn-off sensing of Hg2+ with a minimum LOD as low as 6 nM in the dynamic range from 0 to 0.1 μM. The attractiveness of the present sensing system is that it further acts as a turn-on sensor for GSH detection with good selectivity. The feasibility of the present sensing system is also examined using pond water samples for the detection of Hg2+. Thus, the present sensing system is reliable for sensing and several another analytical applications. [ABSTRACT FROM AUTHOR]

An illustration of development of N,S-CQD-MnO 2 nanoprobe for the GSH detection • Highly fluorescent N,S-CQDs is synthesized hydrothermally with high QY. • N,S-CQDs-MnO 2 nano-composite based nanoprobe is designed for the rapid detection of GSH. • The proposed sensing system possesses high sensitivity and selectivity with a detection limit 0.012 μM. • To check the reliability, the developed method is fruitfully applied on human A549 cells and blood serum sample. In present study, the N,S-CQD-MnO 2 nano-composite is designed, which can perform as a sensitive nanoprobe for the 'off-on' sensing of GSH. The fluorescent N,S-CQDs were synthesized from the hydrothermal treatment of tartaric acid and taurine precursors. The synthesized N,S-CQDs exhibit strong blue emission with the high QY up to 47.4 %. MnO 2 nanosheet significantly quenches the blue fluorescence emission of N,S-CQDs by the phenomenon of fluorescence resonance energy transfer and strong electrostatic interactions between the N,S-CQDs and MnO 2 nanosheet. This reaction system could also work as off-on nanoprobe for GSH detection; the introduction of GSH into the reaction system reappears the fluorescence emission of N,S-CQDs by eradicating the fluorescence resonance energy transfer. Moreover, it is also found that the as-prepared N,S-CQD-MnO 2 based nanoprobe show very low cytotoxicity and good biocompatibility. The calculated detection limit is found to be 0.012 μM in a GSH concentration having a linear range of 0.1-0.7 μM. Interference study confirmed that the designed sensing system is specific toward the GSH detection compared to different amino acids along with some other biomolecules and metal interfering ingredients. Furthermore, the proposed method is successfully applied for the in vitro detecting and imaging GSH in A549 human lung cancer cells. Apart from this, the practicability of the proposed sensing system is also successfully applied in the quantification of GSH from human blood serum. Thus, our designed nanoprobe could be trustworthy for the several analytical and disease diagnosis. [ABSTRACT FROM AUTHOR]