Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

Design and Application of Fluorescent Probes to Detect Cellular Physical Microenvironments

The microenvironment is indispensable for functionality of various biomacromolecules, subcellular compartments, living cells, and organisms. In particular, physical properties within the biological microenvironment could exert profound effects on both the cellular physiology and pathology, with parameters including the polarity, viscosity, pH, and other relevant factors. There is a significant demand to directly visualize and quantitatively measure the fluctuation in the cellular microenvironment with spatiotemporal resolution. To satisfy this need, analytical methods based on fluorescence probes offer great opportunities due to the facile, sensitive, and dynamic detection that these molecules could enable in varying biological settings from in vitro samples to live animal models. Herein, we focus on various types of small molecule fluorescent probes for the detection and measurement of physical parameters of the microenvironment, including pH, polarity, viscosity, mechanical force, temperature, and electron potential. For each parameter, we primarily describe the chemical mechanisms underlying how physical properties are correlated with changes of various fluorescent signals. This review provides both an overview and a perspective for the development of small molecule fluorescent probes to visualize the dynamic changes in the cellular environment, to expand the knowledge for biological process, and to enrich diagnostic tools for human diseases.

A Carbazole-based Fluorescent Turn-off Chemosensor for Iron (II/III) Detection in a Dimethyl Sulfoxide

We designed a novel carbazole-based chemosensor from 2-(N-hexylcarbazol-3'-yl)-pyridine-5-carbaldehyde which was named probe 7b. The main purpose of this study is to investigate whether metal ions in liquid media can be detected with probe 7b. The details were presented in this paper. First, the molecular absorption and fluorescence properties of probe 7b were characterized by spectrophotometers. Then, several methods were applied to check its sensing properties. The results showed that probe 7b has a sense towards Fe3+ ion than other interfering metal ions. The selectivity and sensitivity of probe 7b towards Fe3+ were very satisfactory to use in applications. Also, it was observed that when aqueous Fe3+ ion solutions were added to probe 7b in dimethyl sulfoxide (DMSO), the fluorescence intensity of probe 7b decreased. This situation (turn-off of emission) is due to the paramagnetic effect between probe 7b and Fe3+ ions. The limit of detection (LOD) value was found as 1.38 nM for probe 7b. This value is very small to compete with its counterparts in the literature. A real sample experiment indicated that probe 7b can detect Fe3+ ions more than other ions in real media, too. As a result, it was deduced that probe 7b is a very strong candidate to use in sensor technology.