Acidic Dye
Acidic Dye - Related Videos
09:46
Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing
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Cited by 12 •
2016
Here, we present a protocol to use pre-synthesized polymeric products derived from fungal laccase-catalyzed polymerization of plant phenols, either with or without mordant agents (e.g., FeSO4), to induce detergent-resistant keratin hair dyeing within 2.5 hours.
08:36
FM Dyes in Vesicle Recycling
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2023
FM dyes are a class of fluorescent molecules that has found important use in studying the vesicle recycling process. By virtue of a chemical structure, these molecules can insert themselves into the outer leaflet of phospholipid bilayer membranes. After membrane insertion, they are internalized into the cell via endocytosed vesicles, and released when these vesicles recycle back to the membrane. Since, these dyes fluoresce strongly in the hydrophobic environment within membranes and weakly in...
10:30
Dye-sensitized Solar Cells
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2023
Source: Tamara M. Powers, Department of Chemistry, Texas A&M University Today's modern world requires the use of a large amount of energy. While we harness energy from fossil fuels such as coal and oil, these sources are nonrenewable and thus the supply is limited. To maintain our global lifestyle, we must extract energy from renewable sources. The most promising renewable source, in terms of abundance, is the sun, which provides us with more than enough solar energy to fully fuel our...
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...
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...
FAQs
In aqueous solution, the dye’s negatively charged chromophore is attracted to positively charged regions within cells, including basic proteins. This electrostatic interaction helps create contrast between cellular components and their surroundings. The resulting distribution allows microscopy to distinguish structures according to where the dye accumulates, rather than producing an undifferentiated color across the entire specimen.
Certain acidic dyes remain outside the cells and color the surrounding field, producing a negative-staining preparation. Because the cells themselves remain relatively unstained, their outlines stand out against the darker background. This arrangement is especially useful for observing microbial shape and size, and it can make capsules visible when the dye does not enter the cells.
Eosin is useful for histological examination because it highlights cytoplasm and extracellular components in tissue sections. Nigrosin, by contrast, supports negative staining of microorganisms and can improve visualization of cell shape, size, and capsules without penetrating the cells. The choice therefore depends on whether the investigation focuses on tissue components or microbial morphology.
Negative staining places contrast around microorganisms rather than relying on dye penetration into the cells. This preserves a visible outline against the stained background, helping observers assess cell shape and size. When capsules are present, the preparation can also make them easier to recognize, providing morphological information that supports cell identification during microscopy.
For tissue analysis, eosin is an appropriate example because it highlights cytoplasm and extracellular components. These staining patterns help distinguish cellular material from surrounding structures during histological examination. In microbial studies, a different preparation using nigrosin may be more informative when the main goals are to visualize cell dimensions, shape, or capsules.
Acidic dye preparations can reveal differences in cellular structures, tissue components, and microorganism morphology. Depending on the dye and staining pattern, microscopy may show cytoplasm, extracellular material, cell shape, cell size, or capsules. These observations support cell identification, tissue analysis, and broader investigation of microorganisms in biological research.