mRNA purification with magnetic beads

There are various methods that can be used to purify mRNA from the total RNA in an extract. For example, using column separation (similar to the DNA extraction method) or using magnetic beads, which is described below.

The magnetic beads with oligodT attached will bind selectively to the mRNA molecules since mRNAs typically include a polyA tail. When placed in the magnetic rack the beads containing attached mRNA will be separated from the solution. We can then pipette the solution containing all the unwanted materials, and wash the beads using 80% ethanol. After several rounds of washing we can elute (separate) the mRNA molecules from the magnetic beads and transfer them to a new tube.

Magnetic beads can also be used for the purification of other molecules. Read up on the purification of DNA to learn how the magnetic beads work.