In-depth investigation of the interaction between DNA and nano-sized graphene oxide

Graphene oxide (GO) has been harnessed in diverse biomedical applications such as drug delivery, biomolecule detection and enzymatic activity assay for a decade. In specific, optical biosensors have been developed based on the preferential binding of single stranded nucleic acid on GO and fluorescence quenching capability of GO. Recently, nano-size GO (NGO), which is smaller than micro-sized large GO (LGO), was employed for live cell imaging of various biomarkers and intracellular RNA. However, in contrast to the expanded applications of size controlled NGO, in-depth study on the interaction between DNA and NGO was not sufficiently carried out. Here, we investigated the DNA length dependent interaction between DNA and NGO. By using three DNA strands having different lengths, we observed (1) kinetics and capacity of DNA adsorption, (2) kinetics and sensitivity of sequence specific desorption of DNA and (3) relative strength of DNA interaction with NGO compared to LGO. Present study will give useful information on the effect of GO size to its interaction with DNA, which are important in developing robust biosensors based on GO and DNA.