title: Water-soluble nitric oxide-releasing gold nanoparticles.
abstract: The synthesis and characterization of water-soluble nitric oxide (NO)-releasing monolayer-protected gold clusters (MPCs) are reported. Tiopronin-protected MPCs ( approximately 3 nm) were functionalized with amine ligands and subsequently exposed to 5 atm of NO to form diazeniumdiolate NO donors covalently bound to the gold MPC. Diazeniumdiolate formation conditions, NO-release, and nanoparticle stability were examined as a function of the structure of the protecting ligand, pH, and storage time. Despite their aqueous solubility, proton-initiated decomposition of the diazeniumdiolate-modified Tio-MPCs resulted in only modest NO-release (<0.023 micromol/mg) for short durations (<1.5 h). To increase the NO storage capacity of gold nanoparticles, polyamine-stabilized MPCs ( approximately 5 nm) were synthesized with significantly enhanced NO-release properties (0.386 micromol/mg) and durations (up to 16 h). Transmission electron microscopy, thermogravimetric analysis, nuclear magnetic resonance spectroscopy, elemental analysis, and UV-vis spectroscopy were used to characterize both nanoparticle systems before and after NO exposure. The MPCs represent the smallest water-soluble NO-release nanoparticles to date (3-5 nm).
authors: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors: Mark A
authors: MA
authors: Polizzi
authors: Nathan A
authors: NA
authors: Stasko
authors: Mark H
authors: MH
authors: Schoenfisch
mesh_terms: D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D010316:Particle Size; D011073:Polyamines / Q000138:chemical synthesis / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013997:Time Factors; D008625:Tiopronin / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D011073:Polyamines; D014867:Water; D009569:Nitric Oxide; D006046:Gold; D008625:Tiopronin