Nanoporous gold (NPG) has many technological applications. It can be prepared by various means of which dealloying; a corrosion-based technique is the most common, as the selective dissolution of the more reactive metal leads to an interconnected network of pores. A novel electrochemical cycling technique has been reported to tailor the pore size of NPG in the range from 50-100 nm and the resulting structure has been characterized using scanning electron microscopy (SEM). Since the well-defined pore morphology of NPG also opens up avenues for potential applications we study the effect of additives on the gold surface in different electrolytes and note the structural changes. The effect on pore size variations after annealing the surface of NPG by varying the electrolyte solution and the number of electrochemical cycles has been studied with the objective of studying the effect of these variations on an impedance assay of carbohydrate-lectin binding. An interesting feature of NPG is its large surface area and ability to form stable gold-thiolate bonds owing to which enzyme/protein immobilization can be performed on its surface by covalently linking via self-assembled monolayers (SAMs). This study, which involves the adsorption of proteins on SAMs, is of importance as it mimics the environment as on the cell surface. The techniques of atomic force microscopy (AFM) and electrochemical impedance spectroscopy have also been used to examine the immobilization of dendrimer species within nanoporous gold (NPG) monoliths. Dendrimer macromolecules can contact with multiple binding sites on a lectin and we explore this multivalency. AFM has been used for characterizing polyamidoamine (PAMAM) dendrimers immobilized covalently on the surface of NPG monoliths. The PAMAM dendrimers may also prove of interest as linkers for the presentation of carbohydrate units on the NPG surfaces for selectively binding lectins or other carbohydrate-binding proteins.

Surface characterization and modification of nanoporous gold to detect biomolecular interactions and for applications in glycosciences

246th National Meeting (2013)

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