A NIR Turn-on Fluorescent Sensor For Detection of Chloride Ions in vitro and in vivo

A Porphyrin-based NIR Fluorescent Probe for Bi3+ and Potential Applications

Herein, we have prepared a 5,10,15,20-Tetrakis(4-hydroxyphenyl) porphyrin (P) which acts as a probe for selective and sensitive detection of Bi3+ ions. Probe P was obtained by reacting pyrrole with 4-hydroxyl benzaldehyde and characterized by NMR, IR, and ESI-MS. All photo-physical studies of P were tested in DMSO:H2O (8:2, v/v) media by spectrophotometry and spectrofluorometry respectively. The selectivity of P was tested with different metal ions in solution as well as in the solid phase, only Bi3+ showed red fluorescence quenching while with other metal ions, no such effect was observed. The Job's plot unveiled the 1:1 stoichiometric binding ratio of the probe with Bi3+ and anticipated association constant of 3.4 ×105 M-1, whereas the Stern-Volmer quenching constant was noticed to be 5.6 ×105 M-1. Probe P could detect Bi3+ down to 27 nM by spectrofluorometric. The binding mechanism of P with Bi3+ was well supported with NMR, mass, and DFT studies. Further, the P was applied for the quantitative determination of Bi3+ in various water samples and the biocompatibility of P was examined using neuro 2A (N2a) cells. Overall, probe P proves promising for the detection of Bi3+ in the semi-aqueous phase and it is the first report as a colorimetric and fluorogenic probe.

New insight into the application of fluorescence platforms in tumor diagnosis: From chemical basis to clinical application

Early and rapid diagnosis of tumors is essential for clinical treatment or management. In contrast to conventional means, bioimaging has the potential to accurately locate and diagnose tumors at an early stage. Fluorescent probe has been developed as an ideal tool to visualize tumor sites and to detect biological molecules which provides a requirement for noninvasive, real-time, precise, and specific visualization of structures and complex biochemical processes in vivo. Rencently, the development of synthetic organic chemistry and new materials have facilitated the development of near-infrared small molecular sensing platforms and nanoimaging platforms. This provides a competitive tool for various fields of bioimaging such as biological structure and function imaging, disease diagnosis, in situ at the in vivo level, and real-time dynamic imaging. This review systematically focused on the recent progress of small molecular near-infrared fluorescent probes and nano-fluorescent probes as new biomedical imaging tools in the past 3-5 years, and it covers the application of tumor biomarker sensing, tumor microenvironment imaging, and tumor vascular imaging, intraoperative guidance and as an integrated platform for diagnosis, aiming to provide guidance for researchers to design and develop future biomedical diagnostic tools.

Photoluminescence Sensing of Chloride Ions in Sea Sand Using Alcohol-Dispersed CsPbBr3@SiO2 Perovskite Nanocrystal Composites

In this study, CsPbBr3@SiO2 perovskite nanocrystal composites (CsPbBr3@SiO2 PNCCs) were synthesized by a benzyl bromide nucleophilic substitution strategy. Homogeneous halide exchange between CsPbBr3@SiO2 PNCCs and Cl− solution (aqueous phase) was applied to the determination of Cl− in sea sand samples. Fast halide exchange with Cl− in the aqueous phase without any magnetic stirring or pH regulation resulted in the blue shift of the photoluminescence (PL) wavelength and vivid PL color changes from green to blue. The results show that the PL sensing of Cl− in aqueous samples could be implemented by using the halide exchange of CsPbBr3@SiO2 PNCCs. A linear relationship between the PL wavelength shift and the Cl− concentration in the range of 0 to 3.0% was found, which was applied to the determination of Cl− concentration in sea sand samples. This method greatly simplifies the detection process and provides a new idea for further broadening PL sensing using the CsPbBr3 PNC halide.