Graphene-folic Acid Based Composites For Antibody-targeted Recognition And Sensing

ABSTRACT: Electrochemical biosensing technique has combined advantages of high sensitivity, excellent selectivity, small volume requirements, and the possibility of mass production in microelectronic industry. Electrochemical cytosensor are of practical importance for rapidly and efficiently identifying subtypes of cancer in vitro. And luminescence bioimaging offers a straightforward approach for exploring morphological details of tissues with subcellular resolution and has become a powerful tool for the manipulation and investigation of microspecies from living cells and animals.In this article, we built two kinds of biosensor based on folic acid modified graphene.(1) Rapidly and efficiently identifying subtypes of cancer in vitro are essential in clinical diagnosis. Here we report a detailed study on slightly oxidized graphene (SOG)-based electrochemical cytosensor. The SOG sample was prepared through a mild oxidation approach and fully characterized by means of Raman spectroscopy, UV-vis spectroscopy, cyclic voltammetry, atomic force microscopy and transmission electron microscopy analysis. The SOG maintained the advantage of graphene with high electrochemical activity, and also exhibited good capacity of linking amine derivatives. Assembly of SOG and folic acid enabled the fabrication of an impedance cytosensor with high sensitivity, selectivity and biocompatibility. And the platform allows the detection of-14cells from100μL of cell suspension.(2) Although various quantum dots have been successfully demonstrated for high-performance bioimaging, their biocompatibility needs to be improved for wider and more challenging applications. Herein, using graphene quantum dots with low toxicity, we developed quantum dots-folic acid composites whose toxicities are extremely low to folate receptor non-expressing cells and the composites release strong blue fluorescence in folate receptor expressing cells under the fluorescent microscopy.In conclusion, in this work we have succeeded in preparing SOG-FA hybrids and GQD-FA nanocomposites and using them to build two kinds of graphene nanocomposite-based biosensor, which provide new methods and ideas for the design and fabrication of other biosensors.