A microscope is an essential scientific instrument that allows us to explore the microcosms of life invisible to the naked eye. It magnifies tiny objects, enabling us to study their structure, function, and behaviour in great detail. From the discovery of bacteria to advancements in medical research, the microscope has been an indispensable tool in the progress of science. Microscope slides work alongside a microscope as thin, flat pieces of glass or plastic designed to hold specimens for examination under a microscope. The samples are placed on the slide, and a coverslip is used to secure and keep them flat. Without proper preparation, the quality of the slide may be compromised, leading to inaccurate results. To discover how to avoid this issue, read our latest blog, discussing how to prepare your microscope slides, including why different types of microscope sliding can result in varying outcomes.
Steps for Preparing Microscope Slides
Preparing microscope slides requires several crucial steps to obtain clear, comprehensive, and accurate results. Understanding these steps is critical to ensure optimal results and further scientific discoveries.
- Prepare the Specimen
Specimens must be obtained and cleaned before preparing the microscope slide. Depending on the examined model, cleaning may involve washing, slicing, or cutting the sample into smaller pieces.
- Fixation
Fixation preserves the tissue and prevents decay or decomposition. It can be done using various methods, such as chemical fixation or heat fixation. Chemical fixation is the most common method, in which the specimen is soaked in a preserving solution such as formaldehyde before being placed on the microscope slide. Heat fixation involves applying heat to a sample. This results in bacteria in the sample being killed.
- Embedding
Embedding helps mould and prepare the specimen for sectioning. Most embedding mediums are solid at room temperature, and once applied, they are cured at a temperature that varies depending on the medium. Paraffin, wax, and resin are commonly used as embedding media.
- Sectioning
After embedding, a process is undertaken in which a specimen is cut into thin slices to make it possible to view it under a microscope. This process is called sectioning. This is done using a microtome and a blade to cut the model into thin sections that can fit on the microscope slide.
- Staining
Staining makes it easier to contrast or identify specific specimen cell types and highlight the model’s essential features. Various stains, such as basic or acidic dyes, can be used. A basic stain is a positively charged dye; an Acidic stain is a negatively charged dye. Basic dyes commonly used are basic fuchsin, crystal violet, malachite green, methylene blue, and safranin typically serve as positive stains. Whereas acidic dyes used include acid fuchsin, eosin, and rose bengal.
- Mounting
The slide must be sealed after staining to prevent evaporation and damage to the specimen. A coverslip is placed over the model using a mounting medium, such as glycerin.
Types of Microscope Sliding
Depending on the type of specimen being examined, microscope slides can be prepared differently to produce different results. Choosing the appropriate technique is essential to achieve the best results.
Wet Mount
To perform the wet mount technique, the user must suspend the specimen in a drop of liquid, usually water, on a microscope slide and then cover it with a coverslip. This method is useful when a brief examination of live specimens or temporary viewing of a non-stained model is needed. However, the wet mount technique does not preserve the sample, and the liquid may evaporate.
Dry Mount
The dry mount technique involves mounting the specimen without using a liquid medium. The model is air-dried, then placed on the centre of the slide and covered with a coverslip. While the dry mount is practical when managing larger specimens, where staining is unnecessary and quick examination is needed, the dry-mounted method makes storing slides difficult. This is because dry-mounted models tend to crack and become distorted.
Smear Mount
Letting specimens air dry after smearing them on the microscope slide is known as the smear mount technique. Living organisms, such as blood cells and bacterial colonies, are examples of specimens for which the smear mount is used. One of the drawbacks of the smear mount method is there may be scenarios where samples being used may need to be distributed evenly; using the smear mount method may cause the specimen to be distorted, resulting in an unclear image.
Squash Mount
You must use the squash mount technique to view cells in a three-dimensional form. This method involves compressing a specimen on a slide and causing its cells to spread out. Animal tissues and plants are usually examined using the squash mount technique. The disadvantage of the squash mount is that the specimen may be fixed during the preparation process, making it difficult to compress.
Sectioning
The method where a model is cut into thin sections is referred to as sectioning. Before the slice can be viewed under the microscope, it should be stained or mounted on a slide. Using this technique, a viewer can zero in on tissue details of the thin slices instead of a three-dimensional object.
Preparing microscope slides is crucial for obtaining precise, detailed, and accurate results when examining specimens under a microscope. Understanding the different microscope sliding techniques and types of microscope sliding is essential to select the most suitable method and achieving the best possible outcomes. Some approaches may be simpler and more efficient than others; however, each has advantages and disadvantages depending on the studied specimen. At Techmate, our extensive catalogue of lab supplies features a wide variety of microscope slides compatible with different microscope sliding techniques. Feel free to browse our products to find the slides you need or reach out to our knowledgeable team who will gladly assist you in finding the ideal option for your specific requirements.
