Evaluation of Cell Viability with a Single Fluorescent Probe Based on Two Kinds of Fluorescence Signal Modes.

Accurate evaluation of cell viability is important for dosage tests of anticancer drugs, pathology, and numerous biological experiments. However, due to the serious insufficieny of fluorescent probes, which can distinguish various cell states, the study of cell viability is immensely limited. To resolve this issue, we design and synthesize a new probe ACD-E to monitor cell viability with two kinds of fluorescence signal modes, the first single fluorescent probe that can distinguish three different cell states and furnish accurate information in biological experiments. ACD-E can discriminate live and dead cells in a dual-color mode by evaluating cell mitochondrial esterase activity and can also discriminate live and early necrosis cells by determining mitochondrial viscosity in a "turn-on" mode in the near-infrared region. Significantly, the novel ACD-E can also distinguish cell viability in vivo. This work establishes a robust strategy for monitoring multiple cell states using a single fluorescent probe.

A dual-color ESIPT-based probe for simultaneous detection of hydrogen sulfide and hydrazine.

Hydrogen sulfide (H2S) and hydrazine (N2H4) are toxic compounds in environmental and living systems, and hydrogen sulfide is also an important signaling molecule. However, in the absence of dual-color probes capable of detecting both H2S and N2H4, the ability to monitor the crosstalk of these substances is restricted. Herein, we developed an ESIPT-based dual-response fluorescent probe (BDM-DNP) for H2S and N2H4 detection via dually responsive sites. The BDM-DNP possessed absorbing strength in the detection of H2S and N2H4, with a large Stokes shift (156 nm for H2S and 108 nm for N2H4), high selectivity and sensitivity, and good biocompatibility. Furthermore, BDM-DNP can be utilized for the detection of hydrogen sulfide and hydrazine in actual soil, and gaseous H2S and N2H4 in environmental systems. Notably, BDM-DNP can detect H2S and N2H4 in living cells for disease diagnosis and treatment evaluation.

Monitoring cell viability in N-nitrosodiethylamine induced acute hepatitis and detection of hydrazine in solution and gas phase with Dual-function fluorescent probes.

The highly toxic N-nitrosodiethylamine (NDEA) and hydrazine (N2H4) caused severe environmental contamination and serious health risks. Herein, we designed the two-photon ratiometric fluorescent probe (Nap-2), emission maximum shifted from 466 nm to 571 nm, to monitor cell viability of NDEA induced acute hepatitis via esterase activity detection. Furthermore, the probe Nap-2 evaluate the hydrazine (N2H4) content in the solution and gas phase. It is worth mentioning that we used NDEA induced acute hepatitis in the mice and evaluated the negative correlation of esterase activity in the tissue cells and serum with Nap-2. The probe Nap-2 exhibited that acute hepatitis induced by NDEA decreased cell viability. Furthermore, we made convenient test papers using Nap-2 to detect N2H4 in solution and gas phase. After adding N2H4, the fluorescence color changed from blue to yellow and was visible to the naked eye. This work provides a convenient tool and method for evaluating the toxicity of NDEA induced acute hepatitis and detecting N2H4 in the environment.

Design of a ratiometric near-infrared fluorescent probe with double excitation for hydrazine detection in vitro and in vivo.

Hydrazine has a wide range of industrial applications, but it is also a toxic and explosive chemical substance, which brings potential risks to human health and environmental safety. Therefore, rapid and sensitive monitoring of hydrazine is of great importance in environmental sciences and biological systems. In this work, a new near-infrared (NIR) ratiometric fluorescent probe (Ac-HY) was designed to detect hydrazine under double excitation and emission mode. Ac-HY exhibited large stokes shift (130 nm), high selectivity and sensitivity to hydrazine detection. The applications of Ac-HY probe for detecting hydrazine in vapor and imaging hydrazine in lipid droplets and zebrafish. Therefore, Ac-HY can be used to monitor the distribution of exogenous hydrazine in vitro and in vivo.

Early diagnostic imaging of pneumonia with an ultra-sensitive two-photon near-infrared fluorescent probe.

The mortality rate of pneumonia increases significantly with the prolongation of illness. In the pursuit of a tool to accurately diagnose pneumonia in its early stages, we designed and synthesized a two-photon near-infrared fluorescent probe (DCQN) to identify increased concentrations of the inflammation marker SO2. The probe was found to specifically react with SO2 by undergoing a 1,4-addition reaction to generate near-infrared fluorescence with good sensitivity (6 s), a large Stokes shift (110 nm) and low detection limit (1.49 nM). DCQN has near-infrared emission as well as good two-photon performance, which can image exogenous and endogenous SO2 in cells and avoid interference from background fluorescence from cells. Furthermore, this study achieved accurate imaging of a pneumonia lesion site in deep tissues to provide a tool for the fluorescence diagnostic imaging of pneumonia in situ.