Blood-based research has soared to a whole new level due to next-generation sequencing, microarray technologies, and PCR. There are numerous applications from whole-genome sequencing, DNA fingerprinting, liquid biopsy, blood banking, and plenty more. No matter what the application, the prerequisite is concentrated DNA extracted from whole blood. It must be pure, double-stranded, highly concentrated, and intact. The technique used for DNA isolation impacts results and the entire workflow of molecular biology research. It’s essential to modern-day research and diagnostics that blood extraction is done properly and efficiently. DNA extraction is crucial to diagnostic and medical research.
Importance of DNA Extraction from Blood Samples
The earliest DNA extraction was performed in the 1860s. But, of course, the methods of extraction have changed drastically since then. What was cutting edge discovery in 1860 is routine today in the world of clinical research and molecular biology. But it was definitely the first step to many downstream applications. Molecular research requires obtaining high-quality and high-quantity DNA. Blood is essential on many levels, from routine health checks to drug discovery. In addition, it provides a wealth of biological information on human diseases and physiology.
Friedrich Miescher Makes the First DNA Isolation
Friedrich Miescher was investigating the composition of white blood cells (leukocytes) in 1869 when he isolated an unknown substance. He noted it behaved differently to proteins in solution. After he experimented with various acidic and alkali conditions, he had actually obtained the first sample of what is now known to be deoxyribonucleic acid or DNA. As a young scientist, Miescher continued to investigate his discovery and develop new protocols. He first separated the nuclei from the cytoplasm, then isolated the novel precipitate.
Development of DNA Isolation Procedure
Even though Miescher published his isolation protocols in 1871, routine procedures for DNA extraction didn’t fully develop until 1958. Meselson and Stahl completed a DNA extraction from bacterial samples. They used a salt density gradient centrifugation protocol. After that, DNA extraction methods evolved to cover a wide range of biological sources. Researchers began to adapt extraction needs, and technology advanced. Using organic and non-organic reagents, DNA extraction methods continued to follow the same steps. Today, the method has been simplified, automated, and performed using DNA extraction kits.
Methods of DNA Extraction from Whole Blood Samples
There are two main DNA extraction method categories solution-based or solid-phase. Solid-phase sample preparation separates DNA from other compounds based on physicochemical properties. Solution-based protocols use a salting-out technique or organic solvents to extract DNA. Several factors should be considered when choosing the extraction method. Factors such as sensitivity, consistency, ease, and speed are important. Equally worth considering is the type of specialized equipment needed as well as the level of expertise required to operate it. For some, the choice is an all-in-one DNA extraction kit rather than using complex machinery.
The Latest Advancements in DNA Extraction: Magnetic Beads
The newest method of extracting DNA is magnetic bead capture. How does whole blood DNA isolation using magnetic beads work? It starts with magnetic beads that are coated with a matrix of silica which binds nucleic acids. As with many chemical methods, whole blood cells are first lysed using SDS or a similar detergent. Next, the lysed cells are mixed with magnetic beads allowing the DNA to bind the beads. After a few rounds of washing, the magnetic field separates the captured DNA from other unbound cellular contaminants. Finally, a low-salt buffer removes the DNA from the beads.
A Few Tips
DNA extraction methods continue to evolve as technology advances. There are still a few possible problems with magnetic beading, even though it is the fastest method. But no matter which method is chosen, things can always go wrong. Here are a few tips to help ensure you get high-quality, genomic DNA from blood samples.
· Conduct a Pilot Experiment: If you are trying out a new method with lots of blood samples, start small. Perfect and optimize your procedures before spending more money and time further developing the experiment.
· DNA Preservatives: There are several DNA stabilizing reagents available. Liquid reagents are added to blood samples right after isolation. This inhibits nuclease activity and reduces potential contaminating microorganisms. You’ll be able to store unprocessed blood for longer without worrying about DNA degradation.
· Quantity DNA Properly: If your DNA preparation contains contaminates in degraded DNA and RNA, it will influence the final results. Using only one method of quantification will not always catch these invaders. It makes sense to use a combination of agarose gel electrophoresis and spectrophotometry to quantify and visualize genomic DNA. This can save a lot of time and money.
Final Thoughts
Advancements in biochemistry, cell biology, life sciences, and biotechnology have made lab work easier. There is pretty much a kit for every process. However, with the advantages and disadvantages, new laboratory techniques are sure to develop. It’s important in your lab that you choose the appropriate path for DNA extraction from whole blood samples.
References:
https://www.cdc.gov/dpdx/diagnosticprocedures/blood/dnaextraction.html
https://www.sepmag.eu/blog/magnetic-dna-purification-history-recent-developments
https://biomedgrid.com/fulltext/volume8/the-evolution-of-dna-extraction-methods.001234.php
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7080036/
