ABSTRACT
Hypochlorite serves as a significant antimicrobial agent in the human immune system, and its detection is of great importance. Herein, a novel near-infrared BODIPY-based ClO- fluorescent probe (NCS-BOD-OCH3) was designed and synthesized. The emission bands of NCS-BOD-OCH3 concentrated at 595 nm and 665 nm. Since the electron withdrawing group 1,3,4-oxadiazole was formed after the desulfurization reaction, the fluorescence intensity of NCS-BOD-OCH3 decreased significantly in THF/H2O (v/v, 1 : 1, buffered with 10 mM PBS pH = 7.4), which is visible to the naked eye with an obvious color change. NCS-BOD-OCH3 can realize the two-photon up-converted fluorescence emission. The low detection limit was calculated from the titration results, with the figure for NCS-BOD-OCH3/ClO- being 1.15 × 10-6 M. The result of living cell imaging experiment demonstrated that NCS-BOD-OCH3 can successfully detect ClO- in living cells and can serve as a NIR mitochondrial imaging agent. It is an excellent platform for developing NIR ClO- fluorescent probes.
ABSTRACT
A novel triphenylamine-BODIPY based Schiff base fluorescent probe (TPA-BODIPY-OH) with an emission in the near-infrared (NIR) region was designed and prepared by click reaction. TPA-BODIPY-OH showed three emission bands at 510 nm, 598 nm and 670 nm, and can detect Fe3+ and Hg2+ ions with remarkable fluorescence enhancement in THF/H2O (v/v, 1 : 1, buffered with 10 mM HEPES pH = 7.4) based on the hydrolysis reaction of the -C[double bond, length as m-dash]N bond, and naked eye detection was realized with an obvious color change. The stoichiometry between the probe and ions was deduced from a Job's plot, which is 1 : 3 for TPA-BODIPY-OH/Fe3+ and 1 : 2 for TPA-BODIPY-OH/Hg2+, respectively. The dissociation constant value was found to be 1.35 × 10-16 M for TPA-BODIPY-OH/Fe3+ and 2.06 × 10-11 M for TPA-BODIPY-OH/Hg2+. The low detection limit was calculated from the titration results with the values of 5.15 × 10-7 M for TPA-BODIPY-OH/Fe3+ and 6.81 × 10-7 M for TPA-BODIPY-OH/Hg2+, respectively. In order to investigate the biological applications of TPA-BODIPY-OH, a living cell imaging experiment was carried out. The results demonstrate that TPA-BODIPY-OH can be successfully applied as a bioimaging agent in living cells. In addition, amino-group-functionalized silica fluorescent nanoparticles (FNPs) encapsulating the TPA-BODIPY-OH dyes were prepared and characterized by transmission electron microscopy. TPA-BODIPY-OH/SiO2 nanoparticles exhibit good dispersibility, and the quantum yield of FNPs at 657 nm was 42.3%.
