Effects of single-walled carbon nanotubes on the polymerase chain reaction

The effects of single-walled carbon nanotubes on the polymerase chain reaction (PCR) were investigated via quantitative PCR product measurements, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). The results showed that adding single-walled carbon nanotubes (SWCNTs) into the reaction liquid increases the amount of PCR product at SWCNT concentrations below 3 µg µl−1, but this effect is reversed at higher SWCNT concentrations. Similar effects were observed in PCR reactions with or without Mg2+. Both SEM and HRTEM results showed that the DNA templates and Taq enzymes are attached to bundles of SWCNTs in PCR products. XPS results showed that the C 1s binding energy in PCR products increased after reaction, with the emergence of two new peaks beside the main peak compared with carbon nanotubes before reaction, suggesting that there might be a chemical reaction between SWCNTs and PCR components. In conclusion, SWCNTs may increase the PCR efficiency at a concentration range of less than 3 µg µl−1 in the reaction liquid and have the potential to act as catalysts in a variety of biochemical reactions.