Nile Blue Dyes
Oxazine
Oxazine is a heterocyclic compound containing one oxygen and one nitrogen atom in a double unsaturated six-membered ring. The presence of isomers depends on the relative position of the heteroatom and the relative position of the double bond. By extension, these derivatives are also called oxazines. Examples include ifosfamide and morpholine (tetrahydro-1,4-oxazine). Commercially available dihydro-1,3-oxazine is a reagent in the Meyers synthesis of aldehydes. Fluorescent dyes such as Nile Red and Nile Blue are based on aromatic benzoxazines. Cinnabar and cinnabaric acid are two naturally occurring dioxazines derived from the biodegradation of tryptophan. Nile red is an oxazine derivative fluorescent dye.
Figure 1. The 8 existing isomers of oxazine.
Dioxazine
Dioxazine is a pentacyclic compound consisting of two oxazine subunits. A commercially important example is Pigment Violet 23.
Figure 2. Synthetic route to dioxazine dyes.
Benzoxazine
The benzoxazine formed by the reaction of phenol, formaldehyde, and primary amine polymerizes to form a polybenzoxazine network when heated to about 200 ° C (~ 400 ° F). The obtained high molecular weight thermosetting polymer-based composites can be used in applications requiring higher mechanical properties, flame resistance and fire resistance than epoxy resins and phenolic resins.
Nile Blue
Nile Blue (or Nile Blue A) is a stain used in biology and histology. It can be used with live or fixed cells and gives the nucleus a blue color. It can also be used in combination with fluorescence microscopy to stain the presence of polyhydroxybutyrate particles in prokaryotic or eukaryotic cells. Boiling the Nile Blue solution with sulfuric acid produces Nile Red (Nile Blue Oxazolone). Nile blue is a fluorescent dye. The fluorescence shows especially in nonpolar solvents with a high quantum yield.
Figure 3. Chemical structure of Nile Blue.
Nile Blue in DNA Electrophoresis
Nile blue is also apparently used in a variety of commercial DNA staining formulations for DNA electrophoresis, as it does not require the ultraviolet transillumination illumination visible in agarose gels like agarose gels, so it can be used to observe DNA. It can be isolated or used as a dye to help gel extract DNA fragments without being damaged by UV radiation.
Figure 4. Nile blue in water. Left to right: pH 0, pH 4, pH 7, pH 10, pH 14.
Nile Blue in Oncology
Nile blue derivatives are potential photosensitizers in the photodynamic therapy of malignant tumors. These dyes accumulate in tumor cells, especially in lipid membranes, and / or are sequestered and concentrated in subcellular organelles. Using Nile Blue derivative N-ethyl-Nile Blue (EtNBA), it is possible to distinguish between normal and precancerous tissue in animal experiments. In fluorescence imaging by fluorescence spectroscopy. EtNBA has no phototoxic effect.
Synthesis
Nile Blue and related naphthoxazinium dyes can be prepared by acid-catalyzed condensation of either 5-(dialkylamino)-2-nitrosophenols with 1-naphthylamine, 3-(dialkylamino)phenols with N-alkylated 4-nitroso-1-naphtylamines, or N,N-dialkyl-1,4-phenylenediamines with 4-(dialkylamino)-1,2-naphthoquinones. Alternatively, the product of an acid-catalyzed condensation of 4-nitroso-N,N-dialkylaniline with 2-naphthol (a salt of 9-(dialkylamino)benzo[a]phenoxazin-7-ium) can be oxidized in the presence of an amine, installing a second amino substituent in 5-position of the benzo[a]phenoxazinium system. The following scheme illustrates the first of these four approaches, leading to Nile Blue perchlorate:
Figure 5. Synthesis of Nile Blue.
Reference:
- Lin, CW.; et al. Lysosomal localization and mechanism of uptake of Nile blue photosensitizers in tumor cells. Cancer Research. 1991, 51 (10): 2710–9.
Ion Probe
- Calcium Probe
- Chloride Probes
- Copper Probes
- Fluoride Probe
- Iron (III) Probes
- Magnesium Probes
- Sodium Probes
- Zinc Probes
Metal Probe
Organelle Probe
- Endoplasmic Reticulum Fluorescent Probe
- Golgi Fluorescent Probe
- Lysosomal Fluorescent Probe
- Mitochondrial Fluorescent Probe
Other Probes
- Cyanide Probes
- Cysteine Probe
- Fluo-2 AM Probes
- Fluo-2 Probes
- Fluo-3 AM Probes
- Fluo-3 Probes
- Fluorescent Probes for Imaging Bacteria
- Fluorescent Probes for Imaging Bacteria
- Glucose Probes
- Glucose Probes
- Glutathione (GSH) Probes
- Glutathione (GSH) Probes
- Indo-1 Probes
- Nitric Oxide Probes
- Nitric Oxide Probes
- Viscosity Probes
- Viscosity Probes
PH Probe