Gold as a coordinator of an imidazole conjugated dye of BODIPY derivatives for the identification of simple mercaptans.

Rapid detection of mercaptans in materials and the environment is of great help to material analysis and pollutant monitoring. Gold (Au) shows a high affinity to mercaptans. The coordination and steric effect of mercaptans to Au may be used for the development of new fluorescent sensors. It is possible to distinguish simple mercaptans (such as, HS-, thioglycolic acid) from glutathione (GSH) using Au as a coordinator of dye. Herein, a water-soluble fluorescent sensor of an imidazole conjugated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative (BIM) was characterized by spectroscopic methods. BIM showed a large Stokes shift and high affinity to metals. Especially, Au-combined BIM produced a new complex BIMAu showing improved fluorescence emission, which can be quenched by thioglycolic acid and sodium hydrosulfide, but less affected by GSH. The detection limit of thioglycolic acid was 0.014 µM. Both NaSH and thioglycolic acid coordinated with BIMAu, while GSH took Au3+ away from BIMAu. These results indicate that the gold coordination competition between imidazole-substituted dyes and mercaptans is a good method for the development of new fluorescence chemosensors.

A dye-andrographolide assembly as a turn-on sensor for detection of phthalate in both cells and fish.

Phthalates can penetrate the environment and enrich various aquatic organisms through the food chain, which is involved in promoting the growth of breast cancer. It is of current interest to develop new sensors for phthalates. We herein reported a hydrogen-bond competing fluorescent sensor, BANP, for the detection of dibutyl phthalate (DBP). The BANP compound was synthesized by assembling andrographolide (Andro), nitro- and cyano-substituted BODIPY dye (BCN), and polyethylene glycol derivatives (DSPE-mPEG5000). BANP was found to be a turn-on fluorescent probe for DBP in water with a detection limit of 0.13 µg/g; the DBP-water system acts as a hydrogen bond switch to turn on the fluorescence. And BANP fluorescently detected DBP in contaminated fish meat. Moreover, BANP sensed the DBP-induced growth of human breast cancer MCF-7 cells, and the release of Andro in the DBP-cultivated cancer cells inhibited the proliferation of the MCF-7 cells. Taken together, BANP is a DBP-responsive probe for sensitive DBP detection in water, cells, and fish meats. The BANP sensor may be used in both in vitro fluorescence and cellular imaging analyses. Our results show that guest-induced reassembly brings forth significant fluorescence change, which is a promising way of designing new fluorescent probes for the analysis of phthalates in the environment and food.

A Nano-BODIPY Encapsulated Zeolitic Imidazolate Framework As Photoresponsive Integrating Antibacterial Agent.

Drug-resistant bacteria challenge the antimicrobial agents and antibacterial strategy. To develop environmental friendly smart technology for treating pathogens, we report a kind of photoactivated nano-BODIPY (BCNBA@ZIF). First BODIPY compound (BC) was synthesized by coupling phenethyl caffeate (CAPE) with brominated BODIPY through B-O bonds. Next, BC was encapsulated in ZIF-8 together with 2-nitrobenzaldehyde (o-NBA) to form photoactivated BCNBA@ZIF nanoparticles. TEM confirm the structural change of BCNBA@ZIF after illumination. BCNBA@ZIF is less toxic to cells without illumination. Under illumination of blue LED light, the BCNBA@ZIF worked as a photoacid generator initiating the damage of ZIF shell with the release of BC, metal ions, and the production of singlet oxygen for achieving multifunctional antibacterial uses. Therefore, BCNBA@ZIF is a kind of photodriven smart "Domino" agent for bacterial inhibition.