Nucleic acid isolation is the most technically demanding and laborious procedure performed in molecular cloning laboratory. As a researcher, if you still separate "buffey coat" from whole blood to separate genomic DNA, your method is out!
A recent developed DNA extraction method can directly use whole blood 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.
Whole blood is viscous sample. when we process such complex sample with spin column, the membrane may be clogged because of the cell debris and other precipitate, then result in inefficient recovery of samples. When using Bionew™ whole blood DNA purification kit, this problem is never happened, because in the liquid phase the nucleic acid in the lysate is specifically adsorbed to the surfaces of magnetic beads but the precipitate in the lysate isn’t adsorbed.
Then washing the magnetic beads for 2 times to eliminate the impurities, finally eluting pure DNA from magnetic beads.