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Highly luminescent nitrogen and phosphorus co-doped graphene-analogous flakes (NPCGFs) were synthesized by a one-pot simple hydrothermal reaction using β-cyclodextrin (β-CD), vinylphosphoric acid (VPA), and o-phenylenediamine (oPD) as the precursors. VPA, as an important organic P-containing monomer, was selected as the phosphorus source to generate additional conjugated and effective binding sites on the surface of the NPCGFs. This synthetic strategy not only allows enhancement of structural rigidity, but also effectively eliminates surface traps of the NPCGFs, resulting in an improved fluorescence quantum yield (FL QY) of the NPCGFs. Additionally, oPD simultaneously acts as a nitrogen source and enables amino functionalisation of the NPCGF surface in the synthesis process. The NPCGFs (QY, 32.49%) are irregularly shaped with a typical diameter of approximately 54 nm and display strong fluorescence, with excitation/emission maxima of 360/445 nm. It was found that the NPCGFs can serve as a multifunctional FL probe for pH measurement and quercetin (Qc) detection. A linear relationship exists between the decrease in FL intensity and the concentration of Qc in the range from 0.35 to 30 μg mL−1 as well as the pH variation between 4.0 and 7.0. The probe was further applied to the determination of Qc in living cells. [ABSTRACT FROM AUTHOR]

Highly luminescent nitrogen-doped carbonaceous nanospheres (LNCNs) were synthesized by a one-pot hydrothermal reaction of β-cyclodextrin (β-CD) and branched polyethylenimine (BPEI). Both the N-doping and amino-functionalisation of LNCNs were achieved simultaneously. The prepared LNCNs display excellent properties such as high physical and chemical stability, excitation wavelength-independent emission, and high photoluminescence quantum yields. Importantly, the LNCNs exhibit a quenching of photoluminescence in the presence of quercetin (Qc) based on the simple static quenching mechanism, making it possible to quantify concentrations from 0.5 to 80 μg mL−1 with a detection limit of 0.21 μg mL−1. Furthermore, the LNCNs probe was further used for imaging Qc in living cells. Highly luminescent nitrogen-doped carbonaceous nanospheres (LNCNs) were prepared by hydrothermal treatment of β-cyclodextrin (β-CD) and branched polyethylenimine (BPEI) by a one-pot method. As a comparison, β-CD was used as a raw material to synthesize carbon dots in the absence of BPEI. The carbon dots directly synthesized from β-CD exhibited weak blue fluorescence, while the LNCNs displayed a green image under a 365 nm UV lamp. [ABSTRACT FROM AUTHOR]

A novel quinoline fluorescent probe QNP ((E)-N′-(5-chloro-2-hydroxybenzylidene) quinoline-2-carbohydrazide) for detection of Al3+ ion was designed, synthesized and characterized. QNP displayed a high fluorescence enhancement in the presence of Al3+ ion in DMF:PBS (99:1, v/v) solution and the detection limit was as low as 1.25 μM with high selectivity and excellent sensitivity from 0 to 3 μM. The sensing ability of QNP towards Al3+ ion is attributed to the synergistic effect of PET and ICT. Furthermore, the binding stoichiometry between QNP and Al3+ ion is of 1:1 by Job's plot and mass spectrum, and the calculated binding constant is 4.29 × 108 M−1. The detection of Al3+ ion in water samples illustrates that QNP could be applied to the detection of practical samples in the environment. Bioimaging experiments on Hela cells, zebrafish and soybean root tissues demonstrate that it has potential application to investigate biological processes involving Al3+ ion within living cells. A quinoline-based turn-on fluorescence probe for the detection of Al3+ and its bioimaging in living cells, plant, and zebrafish. [ABSTRACT FROM AUTHOR]

Graphical abstract The preparation of superhydrophobic and superoleophilic PI-based nanofibrous membrane for oil-water separation. Abstract Marine pollution and industrial wastewater have caused serious environmental pollution, thereby resulting into an alarming damage to public health in the past decades, hence the high demand for, cost effective, energy-efficient oil-water separation technologies for the removal of oil contaminants from such water. Herein, we report a facile method to fabricate superhydrophobic/superoleophilic membrane by immersing a polyimide (PI)-based nanofibrous membrane into a water/ethanol/ammonia/dopamine mixture, followed by modification with 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT). The PI-based membrane exhibited water contact angle (WCA) above 153°, while the oil contact angle (OCA) approached 0°, thereby promoting an outstanding chemical stability which sustained its superhydrophobicity when immersed in aqueous solutions at different pH values. Additionally, the PI-based membrane possesses ultrahigh flux, high separation efficiency and good reusability in oil-water separation. The aforementioned properties, as well as the easily scale-up preparation process ensure that this promising as-fabricated membrane can be applied for practical environmental applications including treatment of oily wastewater and oil spillage clean-up. [ABSTRACT FROM AUTHOR]

In this work, a novel fluorescent sensor (quercetin-Pluronic-F127 nano-micelles) was prepared by the facile self-assembly method with natural quercetin (Qc) and Pluronic-F127 (F127). Qc-F127 nano-micelles were characterized by TEM which indicated that Qc have successfully entered into the amphiphilic micelle. The nano micelles with sizes of 25 to 40 nm showed a strong green fluorescence (FL). The sensor exhibits high sensitivity and selectivity towards Cu 2+ with a linear range of 5 × 10 −8 –4 × 10 −6  mol L −1 , the detection limit of 1 × 10 −8  mol L −1 . Moreover, the Qc-F127 nano-micelles can be used to detect Cu 2+ in vitro due to their good biocompatibility. Besides Cu 2+ sensing, when Cysteine (Cys) were added, the FL intensity of Qc-F127-Cu(II) system could be restored due to the chelation interactions between Cu 2+ ions and the sulfydryl and amino groups of Cys. So, Qc-F127-Cu(II) system can used to detect Cys, and the linear range and the limit of detection of the Qc-F127-Cu 2+ system were 3 × 10 −7 –3.5 × 10 −5  mol L −1 and 6 × 10 −8  mol L −1 . Moreover, Qc-F127-Cu(II) has been used for imaging of Cys in cells, which demonstrates its values for potential application in biological systems. [ABSTRACT FROM AUTHOR]

A natural isorhamnetin-based fluorescent sensor for highly sensitive and selective detection of copper ions had been studied. The fluorescent sensor isorhamnetin (Iso) after binding to Cu 2+ ions in pH 7.40 buffer solution generated quenching in fluorescent emission intensity. The binding constant value was obtained 1.79 × 10 6 . The sensor Iso can be applied to the quantification of Cu 2+ ion with a linear range of 1.0 × 10 −8 –1.9 × 10 −6 mol L −1 , the detection limit of 4.0 × 10 −9 mol L −1 , and the reproducibility of the sensor is good. The sensor showed high selectivity toward Cu 2+ . As a result, the isorhamnetin fluorescent sensor was successfully applied for determination of Cu 2+ in rivers, lakes, vegetables and fruits with good recovery. [ABSTRACT FROM AUTHOR]

In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27 ± 2.32 MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2 ± 0.03 MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for “semen sensitive” (intravaginal) drug delivery. [ABSTRACT FROM AUTHOR]

A novel acylhydrazone coumarin fluorescent chemosensor C4 for determination of Ni2+ was designed and synthesized with lower detection limit (2.1 × 10−11 M). Water samples and cell imaging experiments illustrated that C4 could be applied to the detection of practical samples and in living cells. • A novel coumarin fluorescent chemosensor for Ni2+ was synthesized. • The fluorescent chemosensor a low detection limit and high selectivity. • C4 could be applied to the detection of practical samples and in living cells. A novel acylhydrazone coumarin fluorescent chemosensor C4 for detection of Ni2+ was designed and synthesized. The experimental results revealed a low detection limit of 2.1 × 10−11 M with high selectivity and excellent sensitivity towards Ni2+. C4 showed a good linear relationship with the concentration of Ni2+ from 1.3 × 10−6 to 1.6 μM. Moreover, a stable complex was formed between C4 and with Ni2+ and the binding ratio was proved to be 2: 1 by Job's plot and mass spectrum. The sensing ability of C4 towards Ni2+ was attributed to parity-forbidden transition according to fluorescence titrations and DFT calculations. The detection of Ni2+ in water samples illustrated C4 could be successfully applied for the detection of Ni2+ in real environmental samples. What's more, the fluorescence microscopy images of Hela cells demonstrated the high potential of the novel biosensor for the investigation of biological processes involving Ni2+, as well. [ABSTRACT FROM AUTHOR]