Charge-tunable absorption behavior of DNA on graphene

Solving the problem of DNA sticking to graphene is very important for the use of graphene in DNA sequence or other DNA sensor technology. In this study, we use molecular dynamics simulation to demonstrate that DNA tends to adsorb on pristine neutralized graphene rather than on graphene with negative charge. This property of graphene could be charge-tuned from DNA-philic to DNA-phobic, and the property is evaluated by the contact angle of DNA absorbed the on graphene surface. With a negative charge, graphene is prone to be DNA-phobic; with a positive charge, or without a charge, it is likely to be DNA-philic. The translocation time of DNA on a graphene nanopore was greatly extended if the graphene nanopore is functionalized by a negative charge. This study could help us to better design a promising device for DNA sequencing by graphene nanopores.