The Study Of Various Nano-Materials On PCR And Their Mechanism

Polymerase chain reaction has been identified as a fundamental technique in contemporary molecular biology research and clinical medicine. This gene amplification technique can increase the number of the copies of target genes by 6 orders of magnitude. Since its initial use in the early 1980s, this technique has been extensively refined and developed in order to improve the specificity and efficiency. Development of various additives to enhance the specificity and efficiency of PCR still remains a great challenge.Here we report the use of dendrimer-entrapped gold nanoparticles (Au DENPs) as a novel class of enhancers to improve the specificity and efficiency of PCR. We showed that the Au DENPs were effective in optimizing error-prone two-round PCR in specificity and efficiency. With the molar ratio between gold atom and amine-terminated generation 5 poly (amidoamine) dendrimer (G5.NH2) in the Au DENPs, the optimum concentration of Au DENPs could be lower and lower. The present study suggests that the molecular mechanism of the enhancing effect of the dendrimer on PCR is presumably due to the interaction of PCR components with the amine groups on the surface of the dendrimers Our hypothesis is that the use of dendrimer-entrapped gold nanoparticles (Au DENPs) with decreased flexibility and close to spherical shape even after being interacted with solid surfaces or interfaces would overcome the drawbacks of pure dendrimers that can easily form a "pancake" shape. In this case, Au DENPs would have much more surface sites to be interacted with PCR components, effectively enhancing the PCR specificity and efficiency.Here we also report the use of polyethyleneimine (PEI)-modified multiwalled carbon nanotubes (MWCNTs) with different surface charge polarities as a novel class of enhancers to improve the specificity and efficiency of PCR. The materials used included the positively charged PEI-modified MWCNTs (CNT/PEI), the neutralized CNT/PEI with acetic anhydride (CNT/PEI.Ac), and the negatively charged CNT/PEI modified with succinic anhydride (CNT/PEI.SAH). We show that the specificity and efficiency of error-prone two-round PCR are greatly impacted by the surface charge polarity of the PEI-modified MWCNTs. Positively charged CNT/PEI could significantly enhance the specificity and efficiency of PCR with an optimum concentration as low as 0.39 mg/L, whereas neutralized CNT/PEI.Ac had no such effect. Although negatively charged CNT/PEI.SAH could enhance the PCR, the optimum concentration required (630 mg/L) was more than 3 orders of magnitude higher than that of positively charged CNT/PEI. The present study suggests that the PCR enhancing effect may be primarily based on the electrostatic interaction between the positively charged CNT/PEI and the negatively charged PCR components.