Pyridinic-N-rich carbon dots in IFE-based Turn-off Fluorometric detection of nerve agent Mimic- Diethyl chlorophosphate and multicolor cell imaging

A dual-emitting fluoroprobe fabricated by aloe leaf-based N-doped carbon quantum dots and copper nanoclusters for nitenpyram detection in waters by virtue of inner filter effect and static quenching principles

Fluorescence sensing technique has been used in environmental analysis due to its simplicity, low cost, and visualization. Although the fruit pulp-based biomass carbon quantum dots (CQDs) have excellent luminescent properties, aloe leaves possess the superiority of being easily accessible in all seasons compared to fruit pulp. Thus, we fabricated Aloe carazo leaf-based nitrogen doping-CQDs (N-CQDs) using a facile hydrothermal approach, which emitted bright blue fluorescence with a quantum yield of 21.4 %. By comparison, the glutathione-encapsulated copper nanoclusters (GSH-CuNCs) displayed strong red fluorescence. A blue/red dual emission based on the N-CQDs/CuNCs mixture was established for nitenpyram detection. At the 350-nm excitation, the N-CQD/CuNCs system produced dual-wavelength emitting peaks at 440 and 660 nm, respectively. Moreover, when nitenpyram was introduced into the system, the fluorescence intensities (FIs) of N-CQDs significantly decreased, whereas the FIs of GSH-CuNCs varied slightly; simultaneously, the solution color changed from bright blue to dark red. Both the spectral overlapping between nitenpyram's UV-Vis absorption and N-CQDs' excitation and almost unchanged fluorescence lifetimes indicated the occurrence of inner-filtering effect (IFE) in the dual-emitting fluoroprobe. In addition, the Stern-Volmer constant (Ksv = 6.92 × 103 M-1), temperature effect, as well as UV-Vis absorption of N-CQD/CuNCs before and after the addition of nitenpyram corroborated the static-quenching behavior. Consequently, the fluorescence-quenching of N-CQDs by nitenpyram was attributable to the joint IFE and static-quenching principles. A good linearity existed between the F660/F440 values and nitenpyram concentrations (0.5-200 μM) with a method detection limit of 0.15 μM. The dual-emitting fluoroprobe provided the satisfactory recoveries (95.0%-107.0 %) for nitenpyram detection in real-world waters, which were comparable with the results of traditional liquid chromatography coupled to tandem mass spectrometry method. Owing to its simple operations, low-cost, and adaptability for on-site outdoor monitoring, the newly developed dual-emitting fluoroprobe possesses great potential applications in routine monitoring of nitenpyram under field conditions.

A highly sensitive fluorescence probe for on-site detection of nerve agent mimic diethylchlorophosphonate DCP

Nerve agents are the most toxic chemical warfare agents that pose severe threat to human health and public security. In this work, we developed a novel fluorescent probe NZNN based on naphthylimide and o-phenylenediamine to detect nerve agent mimic diethylchlorophosphonate (DCP). DCP underwent a specific nucleophilic reaction with the o-phenylenediamine group of NZNN to produce a significant fluorescence turn-on response with high selectivity, exceptional linearity, bright fluorescence, rapid response (<6 s) and a low detection limit (30.1 nM). Furthermore, a portable sensing device was fabricated for real-time detection of DCP vapor with excellent performance. This portable and sensitive device is favorable for monitoring environmental pollution and defense against chemical warfare agents.

Selective detection of rutin at novel pyridinic-nitrogen-rich carbon dots derived from chicken feet biowaste: The role of bovine serum albumin during the assay

A simple fluorescence method is described for measuring rutin dependent on the nitogen-doped carbon dots (NCDs) prepared via simple pyrolysis method from chicken feet biowaste. The as-fabricated NCDs have unique advantages including cost-effectiveness and high quantum yield (42.9 %). The as-prepared NCDs explore an optimal emission band at 430 nm following exciting NCDs at 330 nm. Addition of rutin to blue-emissive NCDs quenched their fluorescence emission by inner-filtration effect (IFE) and static quenching. Under optimized conditions, the fluorescence responses increased as the rutin amount was raised from 100 to 1000 nmol/L with 5.3 nmol/L as a detection limit (S/N = 3). The probe selectivity was improved by adding bovine serum albumin (BSA), which binds other structurally-related compounds (other flavonoids). The as-synthesized NCDs exhibited some advantages towards rutin detection such as: lower LOD value, satisfactorily reproducibility, simplicity, rapidity, selectivity, and stability. The sensing probe was efficiently utilized for determining rutin in different real samples with acceptable results. The sensor offers an efficient biowaste-based approach for the determination of (bio) molecules.

Zirconium-based metal-organic framework loaded agarose hydrogels for fluorescence turn-on detection of nerve agent simulant vapor

Developing reliable sensors that accurately detect deadly chemical gases is critical to global security. Nerve agents are one of the most dangerous chemicals in the world and are often found in gaseous forms in the environment, which remain a challenge to detect because of their low levels. In this paper, a fluorescent probe based on a Zr-based metal-organic framework UiO-66-NH2 was proposed. The specific binding between the Zr-O site of UiO-66-NH2 and diethyl chlorophosphate (DCP) blocked the ligand-to-metal charge transfer (LMCT) process in UiO-66-NH2, thereby enabling the fluorescence turn-on detection of DCP. More importantly, a simple and portable hydrogel soft-solid platform (UiO-66-NH2@Aga) was constructed by incorporating UiO-66-NH2 into the formation process of agarose (Aga) hydrogel for fast and sensitive detection of gaseous DCP. When the hydrogel was exposed to a low concentration of DCP vapor, its fluorescence changed from colorless to bright blue, allowing visualization of the DCP gas for analysis. The UiO-66-NH2@Aga integrated solid-state platform showed an excellent response to DCP vapor in the detection range of 1.98 to 9.90 ppm and with a detection limit of 1.16 ppm. This work opened up a unique way to design a convenient, low cost and practical gas physical examination platform.

A selective dual quenching sensor (EY/BG@CDs) for simultaneous monitoring of gentamicin and ketorolac levels in plasma: a highly efficient platform that caters to the needs of therapeutic drug monitoring

This research work introduces a novel sensor that utilizes two fluorophores to enable simultaneous monitoring of gentamicin sulphate (GNT) and ketorolac tromethamine (KET). The innovative sensor is composed of carbon dots (CDs) derived from black grapes (BG) and eosin Y (EY) dye. The interaction between the studied drugs and EY/BG@CDs sensor components allows for their simultaneous detection where GNT quenches the fluorescence of EY at 535 nm without affecting the fluorescence of CDs, while KET quenches the fluorescence of BG@CDs at 385 nm without impacting EY fluorescence. The BG@CDs probe was successfully characterized using various techniques such as absorption spectrophotometry, spectrofluorimetry, TEM imaging, infrared spectroscopic analysis, and XRD analysis. The suggested methodology was observed to be highly sensitive for the simultaneous determination of GNT and KET in their spiked rabbit plasma samples, with wide linear ranges and low limit of detection (LOD) values. The studied drugs were extracted using a highly selective extraction method involving protein precipitation followed by mixed mode solid phase extraction using an Oasis WCX cartridge. The simultaneous determination of GNT and KET is essential due to the potential interactions between the studied drugs. Therefore, this analysis can be used to evaluate the necessity of dose monitoring and the potential adverse effects of co-administration of these drugs.