KCS

The polymerase chain reaction (PCR) is fundamental technology in molecular biology and diagnosis. In this study, we carried out PCR using polyethylene glycol-engrafted nano-sized graphene oxide (PEG-nGO) to improve specificity and efficiency of PCR. Since GO favorably interacts with single-stranded nucleic acid by π-π stacking and hydrogen bonding, we hypothesized that single-stranded DNAs (ssDNAs) readily bind to GO surface during the PCR. Because GO is insoluble in high salt solution such as PCR mixture, GO was first fabricated into nano-sized GO (nGO) and the surface of nGO was conjugated with polyethylene glycol (PEG-nGO). The PEG-nGO showed enhanced solubility in high salt solution, retaining its preference to the ssDNA; Primers and PCR template DNAs adsorbed onto GO were expected to be properly released or remained on GO surface as the PCR cycles progress. We demonstrated an enhanced reaction specificity in PCR using PEG-nGO in PCR reaction mixture; 1) Heat-denatured template DNAs were adsorbed onto GO and annealed to primer DNAs without re-annealing of the other template DNA strand. 2) Excess primer DNAs that were adsorbed onto GO prevented primer dimerization and/or nonspecific product formation. We suggest that these two properties of PEG-nGO contribute to enhance the PCR specificity and efficiency.