Xanthene-based Hg2+ fluorescent probe for detection of Hg2+ in water/food samples, as well as imaging of live cells, zebrafish and tobacco seedlings.

In this paper, an Hg2+ detection probe, HOS, was prepared with a xanthene as the parent fluorophore. Hg2+-initiated thioacetal deprotection reaction is the detection mechanism of this probe. After testing, the probe HOS was able to accurately determine Hg2+ with a detection limit of 36 nM. It was successfully applied to the detection of Hg2+ in different water samples and shrimp samples, meanwhile, the filter paper strips prepared by HOS were obviously changed from light yellow to dark yellow under daylight, and from green to yellow under 365 nm UV light. Furthermore, probe HOS enabled Hg2+ bioimaging experiments on HepG2 cells, zebrafish and tobacco seedlings under laser confocal microscopy.

A multi-modal probe for trace water and simultaneously monitoring lipid droplets and lysosomes.

Recently, multifunctional fluorescent probes have received more and more attention with the rapid development of fluorescence imaging technology. In this article, a multifunctional fluorescent probe NAP-OH was designed and synthesized. NAP-OH exhibited outstanding polarity-sensing performance and was used to detect trace water in different organic solvents by means of fluorescence emission intensity. The fluorescence spectroscopy results indicated that NAP-OH was highly responsive to trace water in acetone (LOD = 28 ppm). The co-localization experiment and cell starvation imaging showed that the probe NAP-OH could be used to distinguish lysosomes from lipid droplets, showing bright red fluorescence in lipid droplets and weak red fluorescence in lysosomes. The oleic acid stimulation experiment shows that the probe can detect the dynamic changes of lipid droplets while observing lysosomes. In addition, NAP-OH showed great photostability and low cytotoxicity and was successfully used in zebrafish imaging. Therefore, these results indicated that NAP-OH, as a multifunctional fluorescent probe, would be used in trace water detection and biological imaging.

Preparation of oxime compound lipid droplet-specifically labeled fluorescent probe and its application in cell imaging.

Fluorescent probes can facilitate our further comprehension of the functional and physiological roles of LDs and thus promote the development of effective therapeutic approaches. Oxime compounds are widely used due to their good crystallinity and high reactivity. However, the majority oximes fluorescent probes are usually employed for the detection of HCIO, and the application of oximes in fluorescently labeled LDS is poorly reported. In this paper, three kinds of LDs fluorescent probes (NAP-a, NAP-b and NAP-c) with D-π-A structure were synthesized by simple synthesis method with 1,8-naphthalimide as fluorescent matrix and oxime group as electron donor. These probes were highly sensitive to polarity, and possessed good photostability and low cytotoxicity. Co-staining experiments showed that these probes could target LDs and the fluorescence image was green. These probes NAP-a, NAP-b and NAP-c possessed high Pearson coefficient (HeLa cells: 0.91, 0.95, 0.86) and Manders coefficient (HeLa cells: 0.91, 0.96, 0.86) with Nile Red. Interestingly, the dynamic variations in their size, shape and distribution could be clearly observed in the oleic acid-treated cell model of LDs. Imaging of zebrafish was performed and green fluorescence was collected in zebrafish. These excellent properties make oxime compound fluorescent probes a promising fluorescent probes for studying LDs and metabolic diseases. This study opens up a new way for the preparation of LDs fluorescent probe.