title: DNA-modulated photo-transformation of AgCl to silver nanoparticles: visiting the formation mechanism.
abstract: Solution-phase synthesis and post-synthetic bio-modification have continued to play a dominant role in preparation of nanostructured biomaterials. Heterogeneous nucleation and growth that occur much more often in nature, however, remain rarely explored in nano-biomaterials research. We have newly developed a DNA-modulated photoconversion approach to uniform silver nanoparticles that afford DNA-directed recognition and multi-mode imaging. The present study was aimed at understanding the rapid heterogeneous nucleation and growth of AgNPs at the solid-liquid interface with the aid of DNA. Dynamic changes in absorbance, size and morphology of silver nanostructures were monitored and analyzed to clarify the growth kinetics, which indicated a synthetic route involving synchronous growth of silver nanostructures and the fragmentation and consumption of AgCl. Various stabilizers, including polymer and amino acids, were assessed and compared with respect to the efficacy in photoconversion of AgCl. DNA was found to offer the best monodispersity and the smallest diameter for the resultant AgNPs, due to its strong interactions to silver species as well as excellent charge dispersion ability. By controlling the physicochemical property of DNA through choice of pH and ionic strength, we have demonstrated tunable structure and composition of the nanoparticles.
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; Bioengineering Laboratory, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Wang
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Mitomo
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Niikura
authors.affiliation: Bioengineering Laboratory, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan.
authors.forename: Mizuo
authors.initials: M
authors.lastname: Maeda
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan. Electronic address: ijiro@poly.es.hokudai.ac.jp.
authors.forename: Kuniharu
authors.initials: K
authors.lastname: Ijiro
mesh_terms: D004247:DNA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009841:Oligonucleotides / Q000737:chemistry*; D009994:Osmolar Concentration; D010316:Particle Size; D055668:Photochemical Processes; D011205:Povidone / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry*; D012996:Solutions; D055672:Static Electricity; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D009841:Oligonucleotides; D018030:Silver Compounds; D012996:Solutions; D012834:Silver; D004247:DNA; D011205:Povidone; C037548:silver chloride
keywords: AgCl; DNA; Heterogeneous nucleation; Silver nanoparticles