Synthesis, functionalization, and optical sensing applications of graphene oxide

Graphene oxide (GO) has attracted significant research interest in the past decade owing to its large surface area, superior physical and chemical properties, and easy composition with other materials via surface functional groups. Depending on the different applications, GO can be tailored to form either fluorescent emitters or efficient fluorescence quenchers, which represent powerful platforms for fabricating a series of optical sensors to sensitively detect various targets including ions, nucleic acids, proteins, and biomolecules. In this chapter, we have first briefly summarized the synthesis methods and properties of GO, followed by the introduction of the covalent and noncovalent surface functionalization of GO. Finally, the review highlighted the recent progress in optical sensing based on GO for detection of metal ions, nucleic acids, proteins, biomolecules, pathogens and cells, along with GO-based in vivo biosensing and bioimaging.