Depeng Kong

Carbon dots serve as an effective probe for the quantitative determination and for intracellular imaging of mercury(II)

AbstractWe describe a new method for synthesis of water-soluble photoluminescent carbon dots (CDs) by one-pot hydrothermal treatment of adipic acid and triammonium citrate. The CDs have excitation/emission maxima of 340/440 nm, a quantum yield of 0.13, and are shown to be a viable fluorescent probe for the determination of Hg(II). It shows a linear relationship in the 4 to 18 μM mercury ion concentration range. The detection limit is as low as 2.47 μM. The CDs were applied to intracellular sensing and imaging of Hg(II) where they showed low toxicity. Graphical AbstractCarbon dots synthesized by hydrothermal method can be used as “turn-off” fluorescent probe Hg2+ determination. Besides, the carbon dots were applied to intracellular sensing and imaging of Hg2+.

Rhodamine-based ratiometric fluorescent probes based on excitation energy transfer mechanisms: construction and applications in ratiometric sensing

Ratiometric fluorescent probes allow the simultaneous measurement of two fluorescence signals at different wavelengths followed by calculation of their intensity ratio, which can provide more precise measurement results than intensity-based fluorescent probes. Excitation energy transfer is widely used in the design of ratiometric fluorescent probes. Rhodamine is a convenient platform for the construction of “OFF–ON” ratiometric chemosensors. Rhodamine-based ratiometric fluorescent probes based on the excitation energy transfer mechanism can be constructed by conjugated or non-conjugated connections with other chromophores. In this review, we summarized the recent advances regarding rhodamine-based ratiometric fluorescent probes based on excitation energy transfer. We reviewed these probes according to the classification of “through-space” and “through-bond” probes; we focused on the contributions of different donor fluorophores and the types of connections between the energy donors and acceptors.

Cobalt(II) ions detection using carbon dots as an sensitive and selective fluorescent probe

A simple method was designed for detecting cobalt ions (Co2+) based on the analyte-induced fluorescence quenching of carbon dots (CDs). CDs with a quantum yield of 38.7% were synthesized by hydrothermal treatment of Carbopol 934 and diethylenetriamine. Through the metal–ligand interaction, the prepared CDs can allow highly sensitive and selective detection of Co2+. The color change (from transparent to brown) of the solution can be clearly seen with the naked eye. This effective sensing platform shows high sensitivity and selectivity towards Co2+. Moreover, the CDs are also successfully utilized for monitoring the Co2+ content of natural water.

Carbon nanodots prepared for dopamine and Al(3+) sensing, cellular imaging and logic gate operation.

Fluorescent carbon nanodots (CNDs) were synthesized through a facile, economic and green one-step hydrothermal process. The CNDs exhibit various merits including excellent solubility, superior photostability and low toxicity. Besides, the CNDs can be used as an effective fluorescent probe for dopamine and Al(3+). Whats more, this CNDs based fluorescent probe was favorably applied to the analyses of dopamine in biological fluids and Al(3+) in food samples. This CDs based sensing platform shows its potential applications in the field of biology and food analysis with extraordinary advantages such as fast and simple as well as environmental-friendly. Inspired by these results, the prepared CNDs can be utilized as logic gates at the molecular level.

Construction of carbon nanodots/tungsten trioxide and their visible-light sensitive photocatalytic activity.

Herein we designed a simple and effective method for synthesizing carbon nanodots/tungsten trioxide nanocomposite with high photocatalytic activity. The as-prepared carbon nanodots/ tungsten trioxide has strong photoabsorption under visible light irradiation. Then, carbon nanodots/tungsten trioxide was successfully applied to the degradation of methylene blue. The photodegradation efficiency of methylene blue can be reached as high as 100% after 0.5 h visible light illumination. In addition, carbon nanodots/tungsten trioxide could also be used to degrade rhodamine B and methyl orange. Most importantly, the photocatalytic activity of carbon nanodots/tungsten trioxide did not exhibit obvious changes after five cycles. The results indicate that carbon nanodots/tungsten trioxide has potential applications in the degradation of organic pollutants in industrial waste water.

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.

Carbon nanodots prepared for cellular imaging and turn-on detection of glutathione

A simple one-step hydrothermal method was designed to synthesize fluorescent carbon nanodots (CNDs). The resulting CNDs exhibited excellent properties such as good solubility, superior photo-stability and low toxicity. Significantly, the CNDs were found to be an effective fluorescence sensing platform for turn-on detection of glutathione (GSH). The initial fluorescence of CNDs was quenched through an electron transfer process in the presence of dopamine, while the quenched fluorescence was enhanced with the further addition of GSH. Moreover, it showed a good linear relationship between GSH concentration and the relative fluorescence intensity of the system. Significantly, this sensing platform successfully detected GSH in biological fluids, indicating its potential applications in the field of biology.