title: Tunable stabilization of gold nanoparticles in aqueous solutions by mononucleotides.
abstract: Gold nanoparticles are one of the popular nanomaterials, widely used in biosensor applications as well as nanostructure construction. An essential attribute of these gold nanoparticles (Au-nps) is their stabilization against salt-induced aggregation. In this work, utilization of deoxyribonucleotides (dNTPs) as a tunable surface-stabilization agent for Au-nps was investigated. It was found that surfaces of Au-nps are covered by a layer of dNTPs after an adequate incubation with dNTPs solutions. Electrostatic repulsion among dNTP-coated Au-nps could prevent aggregation of Au-nps at a high salt concentration. The strength of dNTP-based protection can be manipulated by changing preparation protocols (e.g., incubation temperature, ionic strength, and ratio of Au-nps to dNTPs). Four different types of dNTPs exhibit different binding affinity to Au-nps and thus various stabilization efficiency in the order of dATP > dCTP > dGTP approximately dTTP. Moreover, this salt-induced aggregation can be reinitiated by the increase of solution temperature, which leads to a partial removal of the protective dNTP layer on Au-nps. The advantage of thermally tunable aggregation/dispersion of Au-nps mediated by dNTP adsorption offers a useful approach for the preparation of biomolecule (oligonucleotides and oligopeptides) modified nanoparticles in applications of bioassay and nanobiotechnology.
authors.affiliation: Bioengineering Graduate Program and Department of Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR.
authors.forename: Wenting
authors.initials: W
authors.lastname: Zhao
authors.forename: Thomas M H
authors.initials: TM
authors.lastname: Lee
authors.forename: Sharon S Y
authors.initials: SS
authors.lastname: Leung
authors.forename: I-Ming
authors.initials: IM
authors.lastname: Hsing
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques; D003854:Deoxyribonucleotides / Q000737:chemistry*; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D003854:Deoxyribonucleotides; D006046:Gold