Yamin Li

A colorimetric and ratiometric fluorescent probe for thiols and its bioimaging applications

A naphthalimide-based colorimetric fluorescent probe containing a disulfide group was designed and synthesized, which could detect the physiological level of GSH quantitatively by a ratiometric fluorescence method and was successfully applied to the imaging of thiols in living HeLa cells.

A highly selective colorimetric and ratiometric fluorescent chemodosimeter for imaging fluoride ions in living cells

A simple but highly selective colorimetric and ratiometric fluorescent chemodosimeter was designed and synthesized to detect fluoride ions (F(-)) in aqueous solution and living cells by virtue of the strong affinity of F(-) toward silicon.

A simple but highly sensitive and selective colorimetric and fluorescent probe for Cu2+ in aqueous media

In this paper, CN-DPA was prepared as an effective colorimetric and fluorescent probe for copper ions (Cu(2+)) in aqueous solution. It exhibits good sensitivity and selectivity for Cu(2+) over other metal ions both in aqueous solution and on a simple colorimetric paper-made test kit. Upon addition of Cu(2+), a remarkable color change from purple to colorless was easily observed by the naked eye, and a fluorescence quenching was also determined. Furthermore, CN-DPA can be used to quantitatively detect Cu(2+). The linear range was 0-5 μM determined by absorption spectrometry. All these selective and sensitive results indicate that CN-DPA could meet the selective requirements for biomedical and environmental application and be sensitive enough to detect Cu(2+) in environmental water samples, even in drinking water, which has a limit of 20 μM defined by the U.S. Environmental Protection Agency.

A highly selective ratiometric fluorescent probe for 1,4-dithiothreitol (DTT) detection.

A highly selective ratiometric fluorescent probe, which contains an aminonaphthalimide fluorophore and a self-immolative spacer for 1,4-dithiothreitol (DTT) detection was designed and synthesized. The probe displays a 66 nm red-shift of fluorescence emission and the color changes from colorless to jade-green upon reaction with DTT. These properties are mechanistically ascribed to the strong reducing capability of DTT.

Fluorescence detection of adenosine triphosphate through an aptamer-molecular beacon multiple probe.

An aptamer-molecular beacon (MB) multiple fluorescent probe for adenosine triphosphate (ATP) assay is proposed in this article. The ATP aptamer was used as a molecular recognition part, and an oligonucleotide (short strand, SS) partially complementary with the aptamer and an MB was used as the other part. In the presence of ATP, the aptamer bound with it, accompanied by the hybridization of MB and SS and the fluorescence recovering. Wherever there is only very weak fluorescence can be measured in the absence of ATP. Based on the relationship of recovering fluorescence and the concentration of ATP, a method for quantifying ATP has been developed. The fluorescence intensity was proportional to the concentration of ATP in the range of 10 to 500 nM with a detection limit of 0.1 nM. Moreover, this method was able to detect ATP with high selectivity in the presence of guanosine triphosphate (GTP), cytidine triphosphate (CTP), and uridine triphosphate (UTP). This method is proved to be simple with high sensitivity, selectivity, and specificity.

A colorimetric and ratiometric fluorescent probe for quantification of bovine serum albumin

A 4-aminonaphthalimide-based ratiometric fluorescent probe 1 employing the internal charge transfer (ICT) mechanism was designed and synthesized to detect bovine serum albumin (BSA). The interaction of 1 and BSA was investigated by fluorescence and UV-vis absorption spectroscopy. Upon treatment with BSA, the probe successfully exhibited a ratiometric fluorescent response at 540 nm and 480 nm. The fluorescent intensity ratio at 540 nm and 480 nm (F(540)/F(480)) increases linearly with BSA concentration in the range of 0-75.0 μg mL(-1) and the detection limit was about 2.4 ng mL(-1). Our strategy is expected to provide a methodology to quantify BSA either by a normal or by a ratiometric and colorimetric way with high sensitivity.

Triphenylphosphine-assisted highly sensitive fluorescent chemosensor for ratiometric detection of palladium in solution and living cells

Accurate and sensitive detection of palladium (Pd) is essential for both environmental and human health applications. This paper describes a triphenylphosphine (PPh3)-assisted highly sensitive fluorescent chemosensor for ratiometric detection of Pd2+ concentrations up to 300 nM with an LOD of 1 nM. During the detection, PPh3 plays a crucial role in improving the sensitivity of this chemosensor. The chemosensor also has suitable water-solubility which allows detection of Pd2+ in solution. Our studies show that it exhibits excellent selectivity toward Pd2+ and undergoes a color change from colorless to yellow to allow visual detection of Pd2+. Besides detection in solution, this chemosensor also shows great potential as an imaging reagent to detect Pd2+ as low as 0.03 ppm in diverse cells.