Nucleic acid isolation

Nucleic acid isolation is any procedure separating nucleic acid from an organism so the genetic material (nucleic acid) can be studied. The is the first step in genomic studies.

Nucleic acid purification is a technique that removes impurities and unused reagents from nucleic acid (DNA or RNA) samples such as cells, tissues or liquid biopsy using a combination of physical and chemical/enzymatic reactions. The isolated nucleic acids can be used for downstream analysis such as PCR, sequencing, cloning, biobanking etc.

Isolation is achieved by cell lysis to disrupt the cell membrane and release the nucleic materials. After the lysis, a chaotropic buffer is used to enhance the binding of the nucleic acid to a solid support which could be either spin columns or magnetic beads. Where a solid support is not used for the binding (i.e. salting-out method), ethanol can be used to precipitate the nucleic acid out of solution. This is followed by a series of washes with chaotropic buffers and ethanol to wash away contaminants and non-specifically bound materials. Finally, the DNA is eluted from either the column or the magnetic beads using an elution buffer.

Lysis can be achieved mechanically or by enzymatic methods or a combination of both for difficult to lyse samples.