Site-selective attachment onto chemical

Site-Selective Attachment of Capture Probes onto Chemical Templates. .. 107... 

Fig. 23 Site-selective attachment of NAs onto chemically patterned surfaces...

To enhance the properties of carbon nanostructures, several strategies have been developed. For example, carbon surfaces are functionalized, modified, and customized to selectively detect molecules, chemicals, and biological compounds in liquid or gas phases. Noncovalent attachment can be utilized to preserve the structure of CNTs by adsorbing the material onto their surface. However, covalent attachment needs the surface of CNTs to have defect sites, often requiring the surface to be chemically activated to bind molecules to their surface. Alternatively, CNTs can be embedded or filled with material, as we will discuss later in this section. 

Procedures suitable for the incorporation of chemical or biochemical substances or ion-exchange sites onto an electrode surface have been developed in various laboratories. " Such modified surfaces can then be used to perform a variety of functions. They have, for instance, been employed to preconcentrate analytes prior to voltammetric analysis and hence impove sensitivity. For example, dimethylglyoxime has been used to preconcentrate nickel and EDTA to preconcentrate silver." If this preconcentration can be achieved in an environment conducive to rapid electron transfer, then sensitivity will be enhanched even further. Alternatively electrocatalysts have been attached to electrode surfaces, and by speeding up what would otherwise be a sluggish electron transfer process, increased sensitivity has been attained. However, this approach yields no added selectivity and a large background must usually be tolerated. 

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