A label-free DNA reduced graphene oxide-based fluorescent sensor for highly sensitive and selective detection of hemin

G-quadruplex structure aptamer (PS2.M) can capture acridine orange (AO) from reduced graphene oxide (rGO). When the AO-PS2.M/rGO mixture is incubated with hemin, the specific binding of hemin with PS2.M results in a release of AO from PS2.M and return of AO back to rGO. Based on the quenching of fluorescence, the target hemin was detected sensitively and selectively, giving a detection limit of 50 nM.