Size-dependent PCR inhibitory effect induced by gold nanoparticles.

In this work, the effect of gold nanoparticles (AuNPs) with diameters of around 5, 10 and 20 nm on PCR efficiency is evaluated respectively using a real-time PCR machine. Gold nanoparticles show no obvious effect on PCR at low particle concentration. When the concentration is increased, PCR inhibition is observed. At the same particle concentration, gold nanoparticles of different sizes show different inhibitory effects on PCR. It is found that Taq polymerase can interact with AuNPs. The interaction is probably due to the binding of polymerase to AuNPs therefore lowering the concentration of free polymerase. It is also found that bovine serum albumin can interact with gold nanoparticles. It is believed that BSA blocks the surface of AuNPs from forming biding sites for polymerase. It can be used as an additive to reverse the inhibitory effect caused by gold nanoparticles.