Live‐Cell Imaging with Water‐Soluble Aminophenoxazinone Dyes Synthesised through Laccase Biocatalysis

Abstract

Aminophenoxazinone dyes with variable water solubilities were assayed for the first time in a live-cell imaging application. Among a library of ten sulfonylated chromophores, one compound gave excellent results as an endocytic marker, showing a precise subcellular distribution. The compound was compared to four commercial vital tracers, including Lucifer Yellow. The first laccase-mediated regioselective synthesis of a diphosphorylated 2-aminophenoxazinone dye was also described. This compound, water-soluble at 10(-2) M, displayed modest fluorescence properties and the ability to complex Mg(2+) and Ca(2+) cations, therefore giving fluorescence quenching.

Red‐Emitting Rhodamines with Hydroxylated, Sulfonated, and Phosphorylated Dye Residues and Their Use in Fluorescence Nanoscopy

“…To the best of our knowledge, no attempts have been undertaken so far to attach phosphoric acid residues directly to fluorescent dyes 19. In this respect, phosphoric acid has an advantage over phosphonic acid,1h, 19b because it is a much stronger acid. For example, p K a 1 and p K a 2 values for primary alkyl phosphates are 1.5–1.9 and 6.3–6.8, respectively,20a whereas for primary alkyl phosphonates, the first and second ionization constants were found to be 2.4–2.8 and 7.8–8.9, respectively 20b.…”

Investigation of 3d-transition metal acetates in the oxidation of substituted dioxolene and phenols

“…Enzymes without specific condition and coordination environment around them might be non-selective viz. xanthane oxidase can generate superoxide in presence of oxygen [124,125], haloperoxidase can catalyze sulfoxidation [126], tyrosinase can perform catecholase activity [127,128] and phenoxazinone synthase activity [127,128], laccase can also perform phenoxazinone synthase activity [129,130], nitrogenase can reduce unsaturated hydrocarbon substrates, cyanate, thiocyanate [131,132]. Although most model complexes of the enzyme CO are copper complexes but a close look at the Mn complexes show that the Mn complexes exhibit good catalytic efficiency which is overall better than any other probed metal complexes suggesting that Mn is the best for similar activity in laboratory or in industry.…”

“…Phenoxazinone containing compounds are also receiving increasing attention for various industrial applications viz. as antifungal and antimicrobial agents, dyes [164] and for the development of fluorescent probes for the detection of hydroxy radicals and live cell imaging [130,[165][166].…”

Novel red fluorophores with superior performance in STED microscopy

“…Red fluorescent labels are particularly useful in life sciences, especially in biological fluorescence microscopy and single molecule spectroscopy (Fu et al 2008;Bruyneel et al 2010), because they require excitation photons of lower energy thus entailing less background due to autofluorescence. In addition, they are particularly attractive for stimulated emission depletion (STED) microscopy (Hell and Wichmann 1994;Klar et al 2000;Dyba et al 2003) because their fluorescence can be stopped with near-infrared wavelengths (typically > 750 nm) that are not only relatively benign to the sample, but also leave the visible spectrum open for the detection of other fluorophores.…”