Application of Bioconjugated Nanoporous Gold Films in Electrochemical Biosensors

Abstract

The conjugation of biomolecules and nanostructured materials in the last decade has opened a promising horizon to many aspects of modern science. Considerable attention has been paid to the development of new nanomaterials with suitable hydrophilicity, high porosity, and large surface area for various biomolecule immobilizations. Nanostructured materials, in particular a nanoporous structure, could provide large surface area for high loading capacities for the biomolecules. A wide variety of biomolecules including proteins and nucleic acids have been employed in this field. Deoxyribonucleic acids (DNAs), Ribonucleic acids (RNAs), aptamers and aptazymes, whose functions are beyond the conventional genetic roles of nucleic acids, are collectively located in the nucleic acids (NAs) category. Also, various proteins including antibodies, enzymes, redox proteins, etc., have been applied as the recognition layer in nanoporous-based biosensors. Many approaches have been adopted for the surface functionalization of porous membranes, in which chemisorption of thiol compounds onto the surfaces of nanoporous gold (NPG) films takes place with high affinity. The NPG film modified electrodes have been used for the construction of novel label-free electrochemical immunosensors for ultrasensitive detection of cancer biomarker using specific antibodies. Nanoporous materials have made it possible to precisely immobilize enzymes and proteins while retaining or enhancing their activities and lifetimes, which is critical for enhancing biosensor performance. There is also an intriguing possibility to functionalize nanoporous materials with smart polymers in order to modulate biomolecular transport in response to either external (e.g., light and magnetic field) or internal stimuli (e.g., redox, enzymes and pH). These eff orts open up avenues to develop smart medical devices that respond to specific physiological conditions. By integrating the advantages of biomolecules with unique capabilities of NPGs such as biocompatibility and high surface activity, biomolecule functionalized nanoporous films (BM-NPG) can open the path to sophisticated design solutions for present scientific problems. The possibilities provided by BM-NPGs are enormous, and some emerging applications include diagnosis and sensing. © 2014 Scrivener Publishing LLC. All rights reserved.