A Novel Sensing Strategy for DNA Analysis Using Nanoscale Graphene Oxide-Coated Microbeads

Graphene oxide (GO) is a powerful material for the detection of various biological targets including nucleic acids, proteins, and metal ions. Herein, we introduce a rapid, sensitive, and selective tool for pathogen detection by combining bead beating-based DNA extraction and graphene oxidebased fluorescence quenching. This combination was achieved by the fabrication of fluorescent dye-tagged probe/GO/glass beads. The target nucleic acid sequence was extracted from Staphylococcus aureus (S. aureus) using a bead beating tool and GO-coated glass beads (GO beads) on which an FITC-tagged probe was adsorbed. The interaction between single strand DNA (ss-DNA) and GO was disrupted by the formation of double strand DNA (ds-DNA), resulting in stronger fluorescence emission in ds-DNA-GO mixture compared with ss-DNA-GO mixture. Therefore, when the target DNA hybridized with the FITC-tagged probes, the probes detached from the GO beads and their fluorescence was renewed. This method allows detection of Staphylococcus aureus at a concentration as low as 10(5) CFU/ml without sample or signal amplification.