ABSTRACT
We report on a novel facile method towards a synthesis of cyclic assembled gold nanoparticles (AuNPs) by mixing each of the DNA-monoconjugated AuNPs, i.e., "DNA building blocks" for cyclic assembly, and UV-induced interstrand crosslinking. By using our designed template DNA for cyclic assembly which possesses complementary sequences for cyclic assembly of the AuNPs, we demonstrated the formation of the cyclic assembly of AuNPs, i.e., triangular and square assemblies of AuNPs, which were confirmed by TEM analysis.
Subject(s)
DNA/chemistry , Gold/chemistry , Nanoparticles/chemistry , Nanotechnology/methods , Cross-Linking Reagents/chemistry , Cyclization , Microscopy, Electron, Transmission , Surface Properties , Ultraviolet RaysABSTRACT
Peroxynitrite (ONOO(-)), a reactive nitrogen species, is capable of nitrating tyrosine residue of proteins. Here we show in vitro evidence that plant phenolic compounds can also be nitrated by an ONOO(-)-independent mechanism. In the presence of NaNO(2), H(2)O(2), and horseradish peroxidase (HRP), monophenolic p-coumaric acid (p-CA, 4-hydroxycinnamic acid) was nitrated to form 4-hydroxy-3-nitrocinnamic acid. The reaction was completely inhibited by KCN, an inhibitor for HRP. The antioxidant ascorbate suppressed p-CA nitration and its suppression time depended strongly on ascorbate concentration. We conclude that nitrogen dioxide radical (NO(2)(radical)), but not ONOO(-), produced by a guaiacol peroxidase is the intermediate for phytophenolic nitration.