Graphene oxide based DNA nanoswitches as a programmable pH-responsive biosensor

We developed a novel programmable pH-responsive biosensor for simple and rapid pH assay based on the change of the fluorescence signal as a result of the conformational changes of DNA probes and their varying affinities to GO in different conformations. Two probes with different contents of TAT in the triplex DNA exhibited a different dynamic response range. By combining these two probes together in a sensor system, we obtained a pH-responsive sensor system displaying an extended dynamic range of 5.0 to 8.0, which covered the whole pH range in varying biological systems.