Meso-substituted-BODIPY based fluorescent biomarker: Spectral characteristics, photostability and possibilities for practical application

Abstract

A fluorescent biomarker based on the boron(III) complex with meso-4-methoxycarbonylbutyl-substituted 3,3′,5,5′-tetramethyl-2,2′-dipyrromethene (BODIPY) was synthesized. The BODIPY exhibits a large extinction coefficient (lgε ∼4.82–5.00) at 496–501 nm and high fluorescence quantum yield (∼77–100 %) in the blue-green region of the spectrum (509–518 nm). The maximal fluorescence quantum yield (φ) is observed in non-polar media (∼100 %) while φ slightly decreases to ∼90 % in alcohols (with the exception of octanol-1) and to ∼77 % in electron-donating dimethyl sulfoxide (DMSO). The BODIPY fluorophore demonstrates high photostability with the half-life of 41.4 and 91 h in toluene and cyclohexane, respectively. The proposed luminophore preferentially stains gram-positive bacteria and can be used for differential staining of gram-positive and gram-negative bacteria in mixed cultures. BODIPY also accumulates in the cytoplasm of the mammalian cells giving polar micro-speckled staining pattern which is more intensive in the tumor cells when compared to the fibroblasts. The pronounced affinity of BODIPY to mitochondria of eukaryotic cells could be used for specific staining of these organelles.