A spectroscopic probe with FRET-ICT feature for thiophenol monitoring in real water samples

A FRET/TICT based multifunctional fluorescent probe for the monitoring of SO2 derivatives and viscosity in living cells and real samples

SO2 derivatives and viscosity are important intracellular indicators, which are closely associated with various physiological metabolisms in organisms. The unregulated contents of SO2 derivatives and viscosity in vivo commonly related to some disorders. In this work, probe JFT was developed relying on FRET and TICT mechanisms for the simultaneous detection of SO2 derivatives and viscosity. JFT can rapidly detect viscosity levels with continuously enhanced fluorescence signals at 582 nm basing on the increasing of viscosity. Moreover, JFT was also sensitive to the changes of SO2 derivatives level with a low detection limit (61.5 nM), rapid responding time (with 16 min), excellent selectivity and anti-interference capacity. JFT could detect bisulfite in real water, wine and food samples with high accuracy and recovery rate. Cell imaging indicated that JFT could monitor the endogenous SO2 derivatives and viscosity in mitochondria. Importantly, JFT could recognize the cancer cells basing on the cell imaging difference of JFT in AGS and GES-1 cells.

A dual-response fluorescence sensor for SO2 derivatives and polarity and its application in real water and food samples

As an important gaseous pollutant, SO2 derivatives generally exist and significantly threaten the environment and organism health. Meanwhile, polarity is a disease-related indicator in the organism's microenvironment, where an unregulated variation may disturb the physiological metabolisms. Hence, a superior FRET-based fluorescent sensor (TLA) is presented to track polarity and sulfur dioxide derivatives by dual emission channel, i.e. an elevated red emission at 633 nm with decreasing polarity as well as a reduced red emission at 633 nm and improved blue emission at 449 nm with increasing concentration of SO2 derivatives. The probe TLA could sensitively detect SO2 derivatives with ultra-large Stokes shift (273 nm), excellent stability, high selectivity, and low detection limit. Importantly, TLA can accurately detect sulfur dioxide derivatives in real food as well as water samples. Besides, TLA was also fabricated as testing strips and applied to detect SO2 derivatives in the solution.

Real-Time Monitoring of Tyrosine Hydroxylase Activity with a Ratiometric Fluorescent Probe

Parkinson's disease (PD) represents the second most widespread neurodegenerative disease, and early monitoring and diagnosis are urgent at present. Tyrosine hydroxylase (TH) is a key enzyme for producing dopamine, the levels of which can serve as an indicator for assessing the severity and progression of PD. This renders the specific detection and visualization of TH a strategically vital way to meet the above demands. However, a fluorescent probe for TH monitoring is still missing. Herein, three rationally designed wash-free ratiometric fluorescent probes were proposed. Among them, TH-1 exhibited ideal photophysical properties and specific dual-channel bioimaging of TH activity in SH-SY5Y nerve cells. Moreover, the probe allowed for in vivo imaging of TH activity in zebrafish brain and living striatal slices of mice. Overall, the ratiometric fluorescent probe TH-1 could serve as a potential tool for real-time monitoring of PD in complex biosystems.

A novel ratiometric fluorescence probe based on the FRET-ICT mechanism for detecting fluoride ions and viscosity

Fluoride ion is not only important for dental health, but also a contributing factor in a variety of diseases. At the same time, fluoride ions and cell viscosity are both important to the physiological environment of mitochondria. We developed a dual-response ratiometric fluorescent probe BDF based on Förster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) mechanism for the detection of F- and viscosity. BDF has an outstanding intramolecular energy transfer efficiency of 97.7% and shows excellent performance for fluorine ion detection. In addition, when the system viscosity increases, the fluorescence emission intensity of BDF is greatly heightened, indicating the possibility of viscosity detection. Finally, based on the fluorescence properties of BDF, we used the probe to detect F- in the toothpaste sample and image exogenous fluoride ions in HeLa cells.

Simple and Commercially Available 6-chloroimidazo[1,2-a]pyridine-2-carboxylic Acid-based Fluorescent Probe for Monitoring pH Changes

Commercially available compounds that can be directly used as fluorescent probes will greatly promote the development of fluorescent imaging. Based on our previously work related to nitrogen bridgehead heterocycles, herein, a commercially available compound, 6-chloroimidazo[1,2-a]pyridine-2-carboxylic acid, has been detected for monitoring pH value (3.0-7.0). The probe proves to have high selectivity and sensitivity, brilliant reversibility, and extremely short response time. The real-time imaging of pH changes in yeast was also conducted.