Nanoporous Gold for Enzyme Immobilization

Abstract

Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules and -especially enzymes. NPG materials provide a high gold surface area onto which biomolecules can either be directly physisorbed or covalently linked after first modifying the NPG with a self-assembled monolayer. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing less than 50 atomic% gold by dealloying procedures. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues.

Comparative Study of the Binding of Concanavalin A to Self-Assembled Monolayers Containing a Thiolated α-Mannoside on Flat Gold and on Nanoporous Gold

“…The SAM preparation used in this study follows established procedures [23, 25, 60] Regardless of whether nanoporous gold, gold wires, or ultraflat gold was used, these gold surfaces were immersed in either single component solutions of αMan-C8-SH (5 mM) or mixed component thiol solution of αMan-C8-SH/OCT of total concentration 10 mM for 24 hours at room temperature. For simplicity, 8-mercaptooctyl α-D-mannopyranoside will be referred to as thiolated α-mannoside or as αMan-C8-SH, and n-octanethiol will be referred to as OCT, throughout this paper.…”

“…Nanoporous gold (NPG) is a nanomaterial currently under intensive investigation due to its high surface area [24, 60] and possession of a localized surface plasmon resonance response [61] that is useful for sensor and assay applications. [62] NPG provides a high gold surface area at a relatively low cost per square centimeter.…”

Electrochemical characterization of globotriose-containing self-assembled monolayers on nanoporous gold and their binding of soybean agglutinin

“…Nanoporous gold (NPG) is a nanostructured form of gold currently under intensive investigation due to its high surface area 42, 43 . Selective dissolution of the less noble metal(s) from an alloy composed of 20–50% gold results in the bicontinuous network of pores and gold ligaments characteristic of NPG 42 .…”

“…Selective dissolution of the less noble metal(s) from an alloy composed of 20–50% gold results in the bicontinuous network of pores and gold ligaments characteristic of NPG 42 . NPG provides a high gold surface area at a relatively low cost per square centimeter of geometric area 44 .…”

Square-wave voltammetry assays for glycoproteins on nanoporous gold

“…Nanoporous gold (NPG) is prepared by selectively leaching less noble metal(s) such as Ag from an alloy with typically 20% – 50% gold [68, 69]. It consists of interconnected pores and ligaments which increase the surface to volume ratio tremendously.…”