Dechao Shi

Highly luminescent organosilane-functionalized carbon dots as a nanosensor for sensitive and selective detection of quercetin in aqueous solution.

The organosilane-functionalized carbon dots (SiCDs) were synthesized using citric acid with N-(b-aminoethyl)-g-aminopropyl methyldimethoxy silane (AEAPMS). The as-synthesized SiCDs were characterized by IR, TEM, XPS, NMR and fluorescence. The SiCDs showed a strong emission at 455 nm with excitation at 365 nm. The SiCDs exhibited analytical potential as sensing probes for quercetin (QCT) determination. pH effect, temperature effect, interferences, and analytical performance of the method were investigated. It suggested that SiCDs exhibited high sensitivity and selectivity toward QCT: the linear ranges of SiCDs were estimated to be 0-40 μM while the limit of detection (LOD) was calculated to be 79 nM.

N, B-doped carbon dots as a sensitive fluorescence probe for Hg(2+) ions and 2,4,6-trinitrophenol detection for bioimaging.

Nitrogen and boron co-doped carbon dots (BCNDs1-3) were prepared from three kinds of borate via a facile hydrothermal method. The as-prepared BCNDs did not shift with the change of excitation wavelength and possess good water dispersibility, strong fluorescence emission with high fluorescent quantum yield of 29.01%, 51.42%, 68.28%, respectively. Subsequently, these BCNDs were exploited as excellent Hg(2+) ion and 2,4,6-trinitrophenol (TNP) probe. The efficient selective detection of Hg(2+) can be attributed to non-radiative electron/hole recombination annihilation through an effective electron transfer process and the detection of TNP can be attributed to the fluorescence resonance energy transfer process (FRET). The results show that the BCNDs2 is the most sensitive fluorescence probe for Hg(2+) ions and TNP detection as low as Hg(2+) 7.3nM and TNP 0.35μM compared with BCNDs1 and BCNDs3. The as-prepared BCNDs possess the advantages of good selectivity, fast response and a broad linear detection. They were applied to sensing and imaging of human umbilical vein endothelial cells, showing low cytotoxicity and good biocompatibility.

P-doped carbon dots act as a nanosensor for trace 2,4,6-trinitrophenol detection and a fluorescent reagent for biological imaging

A simple and rapid method for sensitive and selective detection of 2,4,6-trinitrophenol (TNP) was developed with the use of water-soluble carbon dots (CDs) as a nanosensor. The CDs with a fluorescence quantum yield of 21.8% are easily prepared by hydrothermal treatment of a sucrose phosphate solution. In this sensing system, the fluorescence of CDs would be significantly quenched by TNP, while other nitroaromatic derivatives and common reagents exhibited little influence on the detection of TNP. The efficient selective detection of TNP can be attributed to the fluorescence resonance energy transfer process (FRET). This phenomenon can be used for the selective sensing of TNP with a limit of detection of 16.9 nM and a linear range of 0.2–17.0 μM. The recovery result for TNP in real samples by this assay method was satisfying, demonstrating its potential application as a fluorescence sensor. Furthermore, the resulting CDs solution could replace traditional colorings and was successfully applied for Escherichia coli labeling and intracellular imaging.

New fluorescence probe for Fe3+ with bis-rhodamine and its application as a molecular logic gate

A bis-rhodamine based fluorescent probe R1 for naked-eye detection of Fe(3+) with enhanced sensitivity compared to a mono-rhodamine derivative that shows selectivity for Hg(2+), has been synthesized. The 1:1 stoichiometric structure of R1 and Fe(3+) is confirmed using a Jobs plot estimation and density functional theory calculations. The reversibility of R1 is verified through its spectral response toward Fe(3+) and S(2-) titration experiments. Using Fe(3+) and S(2-) as chemical inputs and the fluorescence intensity signal as outputs, R1 can be utilized as an INHIBIT logic gate at molecular level. Fluorescent imaging for Fe(3+) in living HL-7702 cells have also been successfully performed.

Carbon dots: synthetic methods and applications as fluorescent probes for the detection of metal ions, inorganic anions and organic molecules

Carbon dots (CDs), a new class of fluorescent materials, have recently attracted considerable research interest. CDs have overcome some defects of traditional nanomaterial. In addition to their small size and optical properties, CDs have the excellent advantages of good biocompatibility and are easy to achieve surface functionalization. Since this discovery, CDs can be widely used in the field of biochemical sensing and environmental testing. This article reviews the progress in the research and development of CDs on their syntheses, applications for the fluorescence detection and possible mechanisms. Finally, we have an outlook of the research trends and future prospects of CDs.

RECOGNITION AND FLUORESCENT SENSING OF ZINC IONS USING ORGANIC FLUOROPHORES-BASED SENSOR MOLECULES

Fluorogenic methods in conjunction with suitable probes have emerged as preferable modalities for the monitoring and measurement of trace metal ions. The number of new Zn2+-responsive fluorescent chemosensors has increased substantially in recent years, as a consequence of biologically and environmental importance of zinc ions, comprising organic fluorophore derivatives, biological functional materials and so on. In this review, we highlight recent advances made in the development of Zn2+ fluorescent sensors. This paper focuses on reviewing sensor molecules based on organic fluorophore derivatives, involving quinoline, BODIPY, coumarin, and so forth. On the basis of current research results, novel fluorescent chemosensors for zinc ions derived from organic fluorophores will be synthesized to increase the sensitivity, water solubility, and bio-compatibility of the sensor for in vivo analysis.