Next Generation Sequencing (NGS) libraries require high quality nucleic acid inputs of varying quantities, concentration, and size depending on the library preparation methods and sequencing platforms used. Regardless of these variations, in most instances a magnetic bead-based chemistry is utilised as a portion of the overall protocol. The steps using magnetic bead chemistries fall into two basic categories of function:
1) Sample cleanup: Removes sequencing adaptors or PCR primers, dNTP’s, enzymes or unwanted buffer formulations.
2) Size Selection: Removes unwanted nucleic acid fragment or library molecules that are above or below a specified size range optimal for the downstream sequencing platform.
By varying the ratio of bead chemistry added to the original volume of DNA in solution, the user can alter the size of DNA captured by the beads or left behind in solution.