20 Flow Cytometry Interview Questions and Answers

Flow cytometry is a diagnostic tool used to measure and analyze the properties of cells. The technology is used in a variety of settings, including medical research, clinical laboratories and biotechnology. Understanding flow cytometry can help you better understand how to use the technology and how to answer questions about it during a job interview. In this article, we review some common flow cytometry questions and provide tips on how to answer them.

Flow Cytometry Interview Questions and Answers

Here are 20 commonly asked Flow Cytometry interview questions and answers to prepare you for your interview:

1. What is the main purpose of flow cytometry?

The main purpose of flow cytometry is to analyze the physical and chemical characteristics of cells. This information can be used to identify different cell types, to study cell development, or to diagnose disease.

2. Can you explain what a fluorescence detector is in context with flow cytometry?

A fluorescence detector is a device that is used to detect and measure the fluorescence emitted by cells or other particles as they pass through a flow cytometer. The fluorescence detector is usually made up of a light source, a filter, and a photomultiplier tube. The light source is used to excite the fluorophores in the cells or particles, and the filter is used to select the wavelength of light that is emitted by the fluorophores. The photomultiplier tube is used to detect the light that is emitted by the fluorophores and to convert it into an electrical signal.

3. What’s the difference between flow cytometry and conventional microscopy?

The main difference between flow cytometry and conventional microscopy is that flow cytometry can measure the physical and chemical characteristics of cells in a liquid suspension as they flow by in single file, whereas conventional microscopy can only observe cells that are stationary on a slide.

4. How does a flow cytometer work?

A flow cytometer is a machine that uses lasers and light-sensitive detectors to measure the physical and chemical properties of cells as they flow through a narrow stream. By looking at these properties, the machine can sort cells into different groups based on their characteristics.

5. What are some types of Flow Cytometers?

There are many types of Flow Cytometers, but some of the most popular ones are the BD FACS Aria, the BD FACS Canto, and the BD FACS Calibur.

6. What are the different kinds of detectors used for flow cytometry?

The four main types of detectors used for flow cytometry are photomultiplier tubes, avalanche photodiodes, photodiode arrays, and charge-coupled devices.

7. What do you understand about the Steric Hindrance Effect?

The Steric Hindrance Effect is the name given to the observation that two particles will tend to avoid each other if they are too close together. This is due to the fact that the particles will experience a repulsive force if they are too close. This effect can be seen in many different contexts, but is particularly relevant in the context of flow cytometry. This is because the particles in a flow cytometry sample will be moving around and will therefore be subject to the Steric Hindrance Effect.

8. What are some advantages of using flow cytometry over other cell analysis techniques like hematology, FACS, or ELISA?

Flow cytometry is a very versatile technique that can be used for a variety of different applications. It is very sensitive and can be used to measure a wide range of parameters from a single cell. Additionally, it is a very rapid technique that can analyze a large number of cells in a short amount of time.

9. Can you give me an example of how a flow cytometer would be useful to analyze the immune system?

A flow cytometer can be used to analyze the immune system in a number of ways. For example, it can be used to measure the number of cells in a given sample, the percentage of cells that are positive for a particular marker, the average size of cells, and the average granularity of cells.

10. Why is flow cytometry such a powerful tool for analyzing blood samples?

Flow cytometry is a powerful tool for analyzing blood samples because it can provide a great deal of information about the cells in the sample. This information can include the size of the cells, their shape, their surface markers, and their internal contents. This information can be very helpful in diagnosing diseases and in understanding how the cells in the blood are functioning.

11. Is it possible to use flow cytometry to measure bacterial growth? If yes, then how?

Yes, it is possible to use flow cytometry to measure bacterial growth. One way to do this is by using fluorescent probes that bind to specific molecules in the bacteria. By measuring the amount of fluorescence, you can then determine the number of bacteria present.

12. Are there any limitations of flow cytometry?

There are several potential limitations of flow cytometry. One is that it can be difficult to accurately measure very small particles. Another is that the technique is not well suited for measuring particles that are not uniform in size or shape. Finally, flow cytometry can be expensive and time-consuming, so it may not be practical for all applications.

13. Can you explain what aperture size means in context with flow cytometry?

Aperture size is a measure of the width of the beam of light that is used to excite the cells in a sample during flow cytometry. A smaller aperture size results in a narrower beam of light, which can be more focused but may also result in less light reaching the cells. A larger aperture size results in a wider beam of light, which can cover more cells but may also result in the light being less focused.

14. What is the difference between direct immunofluorescence and indirect immunofluorescence?

Direct immunofluorescence uses a primary antibody that is conjugated to a fluorochrome, while indirect immunofluorescence uses a primary antibody that is not conjugated to a fluorochrome. The primary antibody in indirect immunofluorescence must be detected using a secondary antibody that is conjugated to a fluorochrome.

15. What happens if multiple lasers are used with flow cytometry?

If multiple lasers are used with flow cytometry, it can help to improve the resolution of the data that is collected. By using multiple lasers, different colors of light can be used to identify different cell types or subtypes. This can help to provide more detailed information about the cells that are being analyzed.

16. Can you explain what forward scatter and side scatter mean in context with flow cytometry?

Forward scatter is a measure of cell size, while side scatter is a measure of cell complexity. In general, larger cells will have higher forward scatter values, while cells with more complex structures will have higher side scatter values.

17. Can you explain what autofluorescence is in context with flow cytometry? How can it impact your analysis?

Autofluorescence is when a fluorochrome (a molecule that absorbs and then re-emits light at a different wavelength) is present in a sample without being specifically bound to anything. In flow cytometry, autofluorescence can cause problems with data analysis because it can produce false positives – that is, events that appear to be positive for a particular marker but are actually just background noise. To avoid this, it is important to carefully control for autofluorescence when designing experiments and to use appropriate controls when analyzing data.

18. What is a bead-based assay?

A bead-based assay is a type of assay that uses beads to capture and measure analytes in a sample. This type of assay is often used in flow cytometry, and can be used to measure a variety of analytes including proteins, nucleic acids, and carbohydrates.

19. Can you explain what apoptosis is?

Apoptosis is a type of cell death that is characterized by a number of morphological changes, including cell shrinkage, chromatin condensation, and blebbing of the cell membrane. Apoptosis is a normal process that helps to regulate cell numbers and remove damaged or unwanted cells.

20. Can you explain what a fluorescent protein is? When would it be useful to use one in context with flow cytometry?

A fluorescent protein is a protein that is able to emit light when exposed to certain wavelengths of light. This can be useful in flow cytometry because it allows for specific cells or proteins to be targeted and identified.