Overview of Project
We are going to learn about cellular staining in a biological
workshop and try out three commonly used methods of
cellular staining, namely histochemical staining, Immunohistochemistry and fluorescence dye staining. We will be aiming to carry out the experiments as specified in our instructions, have the desired results, and photograph the process and results.
Our Mission
To carry out experiments to try out 3 methods of cellular staining while understanding how the different staining methods methods work - hematoxylin & eosin (H&E), Immunohistochemistry targeting Vimentin, and fluorescent dye staining using Hoescht fluorescent work on the organelles in the Liver cells.Our Accomplishment
1)Histochemical staining
Used two common histological stains - hematoxylin and eosin, to stain the nuclei and cytoplasm of liver cell samples, which were stained purple and pink respectively. Hematoxylin is positively charged (basic dye), which would stain the nuclei of cells due to the negatively charged phosphate side-groups of DNA causing electrostatic attraction. Similarly, eosin is negatively charged (acidic dye), which would stain the cytoplasm of cells due to the positively charged amino side-groups of many proteins in the cytoplasm of cells.2)Immunohistochemistry
Used a method of using two antibodies, the second which binds to the first, and the second binded to an enzyme which catalyzed a colourless substrate, and the cellular parts which were bound to the first antibody showed up in a brownish colour. In more detail, the first antibody would bind to a certain protein. The second antibody, binded to an enzyme which would later catalyze a colourless substrate, targets the first antibody and binds to it. When the enzyme catalyzes the colourless substrate, the staining occurs. This method is one of the more commonly used methods in biomedical research on cells due to the usefulness and importance of certain proteins.3)Fluorescence Dye Staining
Used a dye that targeted the nuclei of cells, in this case liver cells, and under a fluorescent microscope the stained nuclei showed up as blue spots on a black background. We used Hoescht fluorescent dye to stain the liver cells’ nuclei, and this is possible due to many fluorescent dyes being positively charged which would cause them to easily bind and thus stain the nuclei of cells due to the DNA within being negatively charged. The background was black as the only colour was from the emitted light of the fluorescent dyes, which thus have to be prepared fresh for any experiment.
Our Gains
- Learnt 3 methods of cellular staining and got to try them out
- Got an insight into how cellular staining works and how it is use
What we learnt would be useful if we are planning to study biomedical sciences or biological sciences that would require keen observation and study on the structure of cells, of which cellular staining is a necessary skill due to most cells being transparent/translucent in nature.
