Enhancing the specificity of polymerase chain reaction by graphene oxide through surface modification: zwitterionic polymer is superior to other polymers with different charges

Abstract

Graphene oxides (GOs) with different surface characteristics, such as size, reduction degree and charge, are prepared, and their effects on the specificity of polymerase chain reaction (PCR) are investigated. In this study, we demonstrate that GO with a large size and high reduction degree is superior to small and nonreduced GO in enhancing the specificity of PCR. Negatively charged polyacrylic acid (PAA), positively charged polyacrylamide (PAM), neutral polyethylene glycol (PEG) and zwitterionic polymer poly(sulfobetaine) (pSB) are used to modify GO. The PCR specificity-enhancing ability increases in the following order: GO-PAA < GO-PAM < GO-PEG < GO-pSB. Thus, zwitterionic polymer-modified GO is superior to other GO derivatives with different charges in enhancing the specificity of PCR. GO derivatives are also successfully used to enhance the specificity of PCR for the amplification of human mitochondrial DNA using blood genomic DNA as template. Molecular dynamics simulations and molecular docking are performed to elucidate the interaction between the polymers and Pfu DNA polymerase. Our data demonstrate that the size, reduction degree and surface charge of GO affect the specificity of PCR. Based on our results, zwitterionic polymer-modified GO may be used as an efficient additive for enhancing the specificity of PCR.

Keywords:

• PCR additive
• charge
• pSB
• Pfu DNA polymerase

Acknowledgments

This study is supported by National Basic Research 973 Project (2014CB932004) and the National Natural Science Foundation of People’s Republic of China (31371005, 81571764 and 81171453). We thank Professor Zhiliang Ji from the State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, for his suggestion in the simulation. We thank Doctor Yoav Peleg of the Weizmann Institute of Science, Israel, for his kind advice and revision of the language. We also thank Professor Chuanliu Wu and his PhD student Yaqi Chen for their kind help with all ITC measurements.

Author contributions

All authors contributed toward data analysis, drafting and critically revising the paper and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.