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).

Gold nanoparticle modifies nitric oxide release and vasodilation in rat aorta

“…For our surprise, this procedure reduced the NO release. These results are different of the results obtained by Polizzi et al [15]. In accordance to our finding, Rothrock et al [14] reported that at 37°C the NO donor coupled to AuNPs released low levels of NO.…”

“…Rothrock et al [14] reported the synthesis of gold nanoparticles that was designed to control the NO release. A few years later, Polizzi et al [15] reported the synthesis of water-soluble NO-releasing gold nanoparticles with significantly enhanced NO payloads.…”

Applications of Nanoparticles in Biology

“…Schoenfisch et al have likewise shown that nitric oxide (NO) can be efficiently released at acidic pH from gold nanoparticles. [103] Besides the surface chemistry of nanoparticles, the unique physical properties of nanoparticles have been utilized in the design of DDSs. Ford et al have designed a water-soluble nanocontainer for NO storage based on electrostatic assembly of DHLA-coated quantum dots and cationic dinitro complexes that uses energy transfer from the core to release NO.…”

Modulated nitric oxide delivery in three-dimensional biomaterials for vascular functionality

“…In another study done by the same research group, water-soluble NO-releasing AuNPs were synthesized from Tiopronin-protected MPCs (Tio-MPCs) via similar modifications. [89] Despite the water solubility, the NO-releasing Tio-MPCs could only release modest amount of NO (<0.023 µM/mg) for short durations (<1.5 h). In the same study, they also demonstrated that the NO storage capacity and release stability could be improved by using polyamine-stabilized MPCs, which could release 0.386 µM/ mg NO within up to 16 h after modifications.…”