Using spin column to purify total RNA from samples is conventional method now, which required RNA was adsorbed to the membrane by centrifuge or vacuum, which bring not only RNA but also cell debris and other precipitate to the membrane. The membrane can be clogged because of the precipitate, then result in inefficient recovery of samples.
A recent developed RNA extraction method can directly use Tissue Suspension as the samples. It is the use of magnetic beads covered with nucleic acid–binding matrices. Its theory is nucleic acid (DNA and RNA) in the solution is specifically adsorbed to the surface of magnetic beads because the following action: (i) shielded intermolecular electrostatic forces, (ii) dehydration of the DNA/RNA and beads surfaces, and (iii) intermolecular hydrogen bond formation in the DNA/RNA–beads contact layer.
When using for Tissue Suspension, this method can farthest eliminate the inhibition in the RNA extraction course, because nucleic acid in the suspension is specifically adsorbed to the surfaces of magnetic beads but the precipitate in the suspension isn’t adsorbed. Then after 2 times of wash steps for the magnetic beads the other impurities are eliminated, finally the pure RNA is eluted and can be used in RT-PCR directly.