Yaping Zhong

Brightly near-infrared to blue emission tunable silver-carbon dot nanohybrid for sensing of ascorbic acid and construction of logic gate

Recently, carbon dots (CDs) have drawn extensive attention owing to their unique properties. While more and more research had been focusing on the exploration of CDs as fluorescence sensors, the blue or green fluorescence emission of CDs restricts further applications of CDs, particularly in the biology-relevant fields due to the commonly blue auto-fluorescence of biological matrix. Therefore, the preparation of CDs with strong emission at long wavelengths is highly desirable. For these situations, a facile, straightforward and extra-reductant needless method was established to fabricate silver-carbon dot nanohybrid with enhanced near-infrared fluorescence through metal-enhanced fluorescence (MEF). We applied the Ag-CD nanohybrid as a probe to detect antioxidants such as ascorbic acid in near-infrared window, and the probe possesses a linear range of 0.2-60μM. More importantly, this sensor could not only function in aqueous solution, but also display well selective response in intricate biological fluids. In addition, an IMPLICATION logic gate was constructed based on the unique characteristics of Ag-CD nanohybrid which presages more opportunities for application in single and multiple biological sensing.

Glutathione-protected silver nanoclusters for sensing trace-level Hg2+ in a wide pH range

An effective fluorescence method for the selective and rapid determination of trace-level Hg2+ in a wide pH range had been proposed based on the glutathione-protected Ag nanoclusters (NCs). Factors affecting the fluorescence intensity of GSH–Ag NCs were investigated. We found that the fluorescence intensity of Ag NCs remained high and stable under pH from 4 to 10, which benefits the monitoring of Hg2+ under different pH conditions in real samples. The fluorescence quenching mechanism is also discussed. The fluorescence of Ag NCs could be quenched in the presence of Hg2+ with a detection limit as low as 1 nM. Good linear correlations were obtained over the concentration range from 0 to 2.5 μM under different pH values (pH = 7, pH = 4 and pH = 9). In addition, this method was successfully applied to the determination of Hg2+ in real samples.

Amino-functionalized silica-encapsulated Mn/ZnS quantum dots for the room-temperature phosphorescence determination of graphene oxide in environmental water samples

We developed a simple and sensitive room-temperature phosphorescence (RTP) method for the determination of graphene oxide (GO) in environmental water samples using amino-functionalized silica-encapsulated Mn/ZnS quantum dots (Mn/ZnS@SiO2-NH2) as a phosphorescent probe. The maximum phosphorescence excitation and emission wavelengths of the synthesized Mn/ZnS@SiO2-NH2 nanoparticles were 320 nm and 595 nm. The RTP intensity of the Mn/ZnS@SiO2-NH2 nanoparticles could be quenched in the presence of GO with a detection limit as low as 1.0 mg L−1. Good linear correlations were obtained over the concentration range from 0 to 10.0 mg L−1 with a correlation coefficient of 0.9987, and 10.0 to 25.0 mg L−1 with a correlation coefficient of 0.9979. The phosphorescence quenching mechanism was also discussed. This method was successfully applied to the determination of GO in environmental water samples which allows more opportunities for its application in biological and environmental systems.

Synthesis of Magnetic/Graphene Oxide Composite and Application for High-Performance Removal of Polycyclic Aromatic Hydrocarbons from Contaminated Water

An effective method for rapid and high efficiency removal of Polycyclic aromatic hydrocarbons from contaminated water had been proposed based on the Graphene/silica magnetic nanocomposites (M/GO). Factors affecting the adsorption efficiency of M/GO were investigated and we found that the optimum adsorption pH was 5.5, adsorption time was 20 min and adsorbent concentration was 400 mg⋅L-1 for phenanthrene and 1200 mg⋅L-1 for pyrene, respectively. The adsorption mechanisms were also discussed. The regeneration and reuse experiments showed good reusability of the as-prepared adsorbent. In addition, this method was successfully applied to the rapid and high efficiency removal of phenanthrene and pyrene from real water samples, which presages more opportunities for application in environment and material sciences.