Interaction Between Dyes And Graphene/Carbon Nanotubes

Graphene and carbon nanotubes are two excellent carbon nanomaterials. Because of their outstanding physical, chemical and material properties, they have very good applications. Through physical or chemical modifications of graphene/carbon nanotubes can change the properties of their surface and improve their dispersions in organic solvents. The modifications make they are better applied in various fields.In this article, we modified graphene oxide (GO) to be a partial chemically converted graphene (CCG). This modified method can partly remove the oxides and restore the π-electron conjugated system to some extent. The CCG sheets can interaction with positively charged organic molecules through electrostatic and π-π stacking because of its negatively charge and aromatic domains. In particular, graphene can act as an efficient quencher of an organic fluorophore or inorganic luminescent nanomaterial based on either an energy transfer or electron transfer process. We applied this method to detect bovine serum albumin (BSA) with cyanine dyes. Cyanine dyes can identify BSA, but the strong background fluorescence resulted in low recognition efficiency. Using CCG as an efficient quencher can eliminate the background fluorescence of cyanine dyes. Upon the addition of BSA, the cyanine dyes on CCG’s surface will be competited down, remarkable fluorescent enhancement can be observed. This method can detection BSA successfully with high detection efficiency and low detection limits as to9.5×10-8M.Through testing the interaction between BSA and CCG-cyanine dye complex with different substituents on Cys, we found cyanine dyes containing electron donor can interact with CCG better than cyanine dyes containing electron withdrawing groups. Result in large quenched efficiency when they stick to CCG’s surface. Upon the addition of BSA, the fluorescence enhanced folds are larger too.In addition, carboxylation of the carbon nanotubes can improve the water solubility. Also we introduce the Water-soluble carbon nanotubes to pyrene-viologen/CB[8] system. In DNA gel electrophoresis experiments, the introduction of micro-SWCNTs can extend the charge separated states generated in cleavage process and delay the electronic return, these will improve cleavage efficiency and promote the process of cleavage plasmid pBR322DNA.