Influences of gold and silver nanoparticles in loop-mediated isothermal amplification reactions

Loop-mediated isothermal amplification (LAMP) performed with protein DNA polymerase Bst and DNA chains was influenced by nanoparticles in different ways. The effects of different concentrations of gold nanoparticles (AuNPs) with diameters 10 and 20 nm and silver nanoparticles (AgNPs) 1–10 nm in diameter on the amplification of the pR72H gene of Vibrio parahaemolyticus were investigated. AuNPs with a diameter of 10 nm in 0.6–60 nM concentration accelerated initiation of the LAMP reaction, 3 nM AuNPs reduced the reaction time by about 10 min, whereas 20 nm AuNPs did not, although neither size increased the yield after 60 min. AgNPs inhibited the LAMP reaction both in speed and yield at concentrations of 0.6–60 nM; the yield of amplification was reduced by 50% and 80% for 12 and 60 nM, respectively, after reaction for 1 h. This indicated that strong bactericidal effects of silver are also observed in its nanoparticles. The molecular mechanism of AuNPs and AgNPs in LAMP needs to be explored further, although their size-related electronic, magnetic and optical properties, as well as their ability to affect protein denaturation, or hydrophilic/hydrophobic effects may be involved.