The parent skeleton of Dipyrromethene Boron Difluoride (BODIPY) is a large rigid planar structure, which is composed of two pyrrole rings and a six membered boron nitrogen heterocycle. Because of its superior properties, it is one of the most widely used functional organic fluorescent dyes.
Characteristics of BODIPY
First, the spectral properties of BODIPY dye are very stable and not easily affected by solvent polarity and pH value. This property allows for the design of molecular probes that can work in different solvents, and their pH sensitivity makes them suitable for DNA sequencing and DNA labeling.
Second, its fluorescence quantum yield is generally high, some even can be close to 1.0 in water. The fluorescence quantum yields of most of these dyes are close to 1, and still maintain a high quantum yield in water. In contrast, many other fluorescent dyes may have high quantum yields in organic solvents but very weak fluorescence in water.
Third, because the half peak width of its fluorescence spectrum is narrow, it has good sensitivity as a fluorescent marker. Although the measured samples only exist in trace amounts, the fluorescent probe molecules can also indicate the existence of the samples with significant fluorescence changes. At the same time, the molar absorption coefficient is very large, which is conducive to improve the photosensitivity of fluorescent dyes and make them more widely used in the field of biological analysis.
Finally, it has relatively good light stability. In the process of fluorescence analysis, it will not lead to the rapid photo degradation of the structure of the dye due to the irradiation of stimulated luminescence. Moreover, the molecular structure of the dye does not contain ionic charge. This avoids the possibility of electrostatic interaction between dye molecules and other ions in the solution due to the existence of charge, so as to ensure that the change of spectral signal is only related to the sample to be measured.
Purpose of BODIPY
At present, BODIPY fluorescent dye molecules have been widely used in various fields, such as ion probes, molecular probes, fluorescent probes for biological imaging research, photovoltaic power generation, sensors, optoelectronics, energy transfer systems, photodynamic therapy and molecular switches.
(1) As metal ion probes, BODIPY fluorescent dyes have strong recognition ability for alkali metal ions Mg2+ and Na+. (2) BODIPY fluorescent dyes are used as small molecule probes. Some people have developed no probes based on BODIPY fluorophores. In the presence of NO, two amino groups and nitrogen atoms of NO form a triazole structure with five membered ring. Due to the electron absorption effect of this structure, the photoinduced electron transfer is blocked, the fluorescence quantum yield of the probe is restored to 0.74, and the fluorescence intensity is increased by more than 370 times. (3) BODIPY fluorescent dyes are used as molecular switches, and phenyl selenium substituted BODIPY fluorescent molecular switches (BOD-phse) are used for the detection of H2S in biological cells. (4) BODIPY fluorescent dyes are used in the field of bioanalysis. Due to their high selectivity for GSH, they have been widely used in the detection of GSH in living cells. It is envisaged that derivatives with different functions can be synthesized by changing substituent according to the modifiable structure, which can be well used in various fields.