Characterization of the chemical architecture of carbon-fiber microelectrodes. 1. Carboxylates.
A new method to characterize the chemical architecture of a carbon-fiber microelectrode surface is described. Derivatization of carboxyl groups on the carbon surface with a poly(oxyalkalene)diamine (Jeffamine ED-600), followed by biotinylation of the free amine, allowed the attachment of a fluorescein isothiocyanate (FITC) conjugate of ExtrAvidin. The fluorescence observed after excitation at 488 nm was imaged with a fluorescence microscope equipped with a CCD camera, yielding a spatial map of the distribution of modified carboxyl groups on the surface of the carbon fiber with 0.5-micron resolution. Colloidal gold particles (15 nm diameter) coated with ExtrAvidin were used in place of the FITC-ExtrAvidin, and the carbon-fiber surface was imaged with scanning electron microscopy on a submicron scale. This selective information regarding surface-bound functional groups (i.e. carboxylates) has proven invaluable toward the rational design of novel sensors based on surface-modified ultramicroelectrodes.
Department of Chemistry, University of California, Riverside 92521.
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D001710:Biotin / Q000737:chemistry; D002244:Carbon; D000077482:Carbon Fiber; D002264:Carboxylic Acids; D016650:Fluorescein-5-isothiocyanate; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D013059:Spectrum Analysis, Raman
D000077482:Carbon Fiber; D002264:Carboxylic Acids; D001710:Biotin; D002244:Carbon; D016650:Fluorescein-5-isothiocyanate