eBook: Optimizing Results from Nucleic Acid Isolation - 20

Nucleic Acid Isolation from
Clinical Samples
Addressing the challenges of utilizing fresh frozen tissue samples,
FFPE tissue blocks, and liquid biopsy for NGS.
Andrew Gane
Investigating the roles of both DNA and RNA is essential in a range of scientific fields, including molecular biology, genomics, biotechnology, and epidemiology. To do this, researchers need high-quality
nucleic acid samples to meet the requirements for
sensitive applications, such as next-generation sequencing (NGS).

it enables tissues to be collected over an extended
period of time and the DNA to be isolated from them
in a single day.

Using poor quality or contaminated samples for
these applications might not yield accurate or biologically relevant results. Consequently, there is a
demand for reagents and techniques optimized for
the isolation and purification of high-quality DNA
and RNA from a diverse range of biological sources.

Nucleic acid extraction and purification involves
three key steps:

RNA is considerably less stable than DNA.
Consequently, RNA isolation requires careful handling, processing, and storage. If the smallest amount
of RNase remains, it can degrade the sample.

* Lysis: Breaking the cells open to expose the
DNA and RNA.
* Lipid membrane removal: Treating the
samples with a detergent such as Triton™
X-100 or NP-40.

These sources include fresh frozen tissue samples,
formalin-fixed paraffin-embedded (FFPE) tissue
blocks, and liquid biopsy (e.g., a blood sample).

* Nucleic acid precipitation: Achieved by adding
alcohol to the sample.

The isolation and purification of
nucleic acids

There are also two optional steps during DNA isolation: removal of proteins in the sample(s) by adding
a protease (for example, proteinase K) and elimination of RNA with the use of an RNase (for example,
RNAse A). These steps can minimize the impact of
contaminants and increase DNA stability for longterm storage.

DNA is generally stable when stored under suitable
(frozen) conditions. It is also possible to conduct
DNA isolation, purification, and storage from these
different types of samples in batches. This is useful as

eBook: Optimizing Results from Nucleic Acid Isolation

Table of Contents for the Digital Edition of eBook: Optimizing Results from Nucleic Acid Isolation