Graphene oxide (GO) is attracting considerable interest in many basic and applied research fields including biosensing applications. By adsorbing dye-labeled aptamer on the GO surface, we can prepare the GO aptasensor. The fluorescence from the dye is not observed at the initial stage because of the fluorescence resonance energy transfer (FRET) process between the dye and GO, but it recovers when the aptamer forms complex with the target protein and the dye leaves from the GO surface.As GO is readily dispersed in water, most GO aptasensors have been operated in an aqueous medium. By contrast, we have developed and studied a GO aptasensor fixed on a solid support. One advantage of our system is that we can directly observe phenomena occurring on the GO surface during protein recognition, using surface science analytical tools such as confocal laser scanning microscope (LSM) and atomic force microscope (AFM). To an identical single GO aptasensor fixed on SiO2 surface, we observed the fluorescence recovery (by LSM) and the increase of the thickness (by AFM) after the recognition of the target protein. We also performed AFM observations in solution for observing protein recognition processes in situ.Another advantage is that we can combine the sensor with microfluidics to realize an on-chip GO aptasensor. By fabricating the multichannel structure, we can examine several different samples at one time, which is useful for high-throughput analyses. The microfluidics technology is also used for fabricating GO aptasensor microarray, which integrates the different aptasensor probes in each channel. These developments are useful not only for the practical application of GO aptasensor, but also for the basic research such as a new probe design.

Graphene oxide-based FRET aptasensor on solid support

248th National Meeting (2014)

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