Indigo Dye Formation
Indigo Dye Formation - Related Videos
01:19
Assessing Bacterial Biofilm Formation Using a Cationic Dye-Based Assay
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2026
Begin with a bacterial suspension in nutrient media.Add the suspension to a multi-well plate and incubate.The nutrients in the media facilitate bacterial growth and attachment.The adhered bacteria secrete extracellular polymeric substances consisting of polysaccharides, proteins, and DNA to form a layer of biofilm.Wash multiple times with buffer to remove unbound bacteria.Invert the plate to ensure the removal of residual liquid from the well and allow the biofilm to dry.Treat with a fixative...
03:31
Inducing Blood Clot Formation in the Mouse Brain Using a Photosensitive Dye
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2025
Source: Talley Watts, L., et al. Rose Bengal Photothrombosis by Confocal Optical Imaging In Vivo: A Model of Single Vessel Stroke. J. Vis. Exp. (2015)This video demonstrates a technique to induce blood clot formation in a mouse brain. An anesthetized mouse with a cranial window and a thinned skull undergoes photothrombosis through the activation of a photosensitive dye using high-intensity light. This process generates reactive oxygen species, which damage the vessel walls and trigger clot...
09:52
UV-Vis Spectroscopy of Dyes - Student Protocol
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2020
Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA Absorbance Wavelength ComparisonExpand In the first part of the lab, you'll use ultraviolet and visible light absorption spectroscopy, or UV-Vis absorption spectroscopy, to analyze the absorption characteristics of fluorescein, β-carotene, and indigo dye. To perform UV-Vis spectroscopy, you'll place a solution between a light source and a photodetector. The molecules will absorb light at...
03:59
UV-Vis Spectroscopy of Dyes - Instructor Prep
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2020
Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA Preparation of Dye SolutionsExpand Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed. First, put on a lab coat, safety glasses, and nitrile gloves. Some solutions use hexane or dimethylformamide, so prepare those solutions in a fume hood. Prepare a 1 mM stock solution of fluorescein in water. Measure 0.0166 g of fluorescein...
04:55
UV-Vis Spectroscopy of Dyes - Concepts
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2020
Absorbance When light interacts with a substance, a portion of the light is absorbed while the rest is either reflected or transmitted through it. Substances that we perceive as having a color reflect light in the visible range. The color of the substance that we are able to see depends on which wavelength of light is reflected. A substance that we perceive as blue reflects light in the blue range (430 – 480 nm) of the visible spectrum. According to the color wheel, the same substance absorbs...
FAQs
Glycoside hydrolysis is an essential upstream step because compounds such as indican hold the precursor in a glycoside form. Enzymatic cleavage releases indoxyl, which can then undergo the oxygen-dependent chemistry leading to pigment formation. If this release does not occur, subsequent oxidation and coupling cannot follow the described pathway. This ordering helps explain why processing that promotes hydrolysis influences color development.
Oxygen changes the reaction pathway by oxidizing indoxyl after it has been released. The oxidized indoxyl can then participate in coupling with another indoxyl molecule, allowing the molecular framework of indigo to develop. This dependence on oxygen explains why exposure during processing is associated with color development, rather than treating the blue pigment as present in the original colorless precursor.
Insolubility converts newly formed indigo from a dissolved reaction product into a separable solid. That precipitation provides a practical endpoint for the chemical sequence, because pigment can be separated from the surrounding solution rather than remaining uniformly dispersed. It therefore connects molecular product formation with pigment recovery and supports the use of indigo in dyeing workflows.
The process links three reaction concepts that are central to chemistry: hydrolysis breaks a glycosidic connection, oxidation changes indoxyl after oxygen exposure, and coupling creates a carbon-carbon bond between molecular units. Considering these transformations as a sequence helps explain how molecular changes produce a stable, visibly blue pigment and why chemistry provides the framework for analyzing dye formation.
A practical workflow begins with a glycoside such as indican and an enzymatic hydrolysis step to release indoxyl. The resulting material is exposed to oxygen, allowing oxidation and coupling to proceed. Because the indigo product is insoluble, it precipitates from solution and can be separated. This sequence connects precursor treatment, oxygen exposure, pigment recovery, and subsequent textile-dyeing use.
Its significance extends from explaining color development during processing to practical textile dyeing in traditional and industrial settings. The same chemistry also provides a basis for research on sustainable, bio-based pigment production. Studying the pathway can therefore connect molecular reaction steps with choices about how pigments are produced and applied.