Talanta 68 (2006) 693–699 Electrostatic-assembly metallized nanoparticles network by DNA template Aiguo Wu, Wenlong Cheng, Zhuang Li ∗ , Junguang Jiang, Erkang Wang ∗ State Key Laboratory of Electroanalytical Chemistry, Chinese Academy of Sciences, Changchun Institute of Applied Chemistry, Changchun 130022, China Received 8 June 2004; received in revised form 12 May 2005; accepted 12 May 2005 Available online 27 June 2005 Abstract Eighteen-nanometer gold and 3.5-nm silver colloidal particles closely packed by cetyltrimethylammonium bromide (CTAB) to form its positively charged shell. The DNA network was formed on a mica substrate firstly. Later, CTAB–capped gold or silver colloidal solutions were cast onto DNA network surface. It was found that the gold or silver nanoparticles metallized networks were formed owing to the electrostatic-driven template assembling of positive charge of CTAB–capped gold and silver particles on the negatively charged phosphate groups of DNA molecules by the characterizations of AFM, XPS and UV–vis. This method may provide a novel and simple way to studying nanoparticles assembly conjugating DNA molecules and offer some potential promising applications in nanocatalysis, nanoelectronics, and nanosensor on the basis of the fabricated metal nanoparticles network. © 2005 Elsevier B.V. All rights reserved. Keywords: DNA; Nanoparticle; Network; AFM; Self-assemble 1. Introduction A key goal of nanosized science and technology is the innovation of protocols to the interactions, and the long-range order of various nanoparticels and clusters on different solid substrates. It can offer some novel properties of materials and devices based on the mesoscopic physics, chemistry and catalysis. Biometic “bottom-up” approaches are popularly being explored for the self-assembly of functional devices by molecular and nanoparticulate construct units [1–3]. Among the biological templates that can be used as candidates in nanostructure systems [4–6], DNA molecules, in particu- lar, are promising templates for assemblies from several nanometers up to several tens of micrometers. In addition, the columnar double-helix structure of DNA molecules together with the ability to the negative charge in phosphate backbone of DNA molecules to fastening metal nanoparticles makes them become ideal templates for growing nanowires or ∗ Corresponding authors. Tel.: +86 431 5262057; fax: +86 431 5689711. E-mail addresses: zli@ns.ciac.jl.cn (Z. Li), ekwang@ns.ciac.jl.cn (E. Wang). other intricate nanostructures by binding together metal or semiconductor nanoparticles [4–6]. To date, both covalent and non-covalent self-assembly strategies have been widely used to assemble nanoscale inorganic particles into two- and three-dimensional meso- scopic and macroscopic structures using DNA since Coffer et al. took advantage of DNA as a building block for various nanostructures [6–15]. Braun et al. have reported an example that a silver nanowire which is formed using the DNA as a skeleton [6]. Current–voltage measurement showed the potential use of these nanowires. Subsequently, some groups have also described some methods of DNA-based template Pd nanoclusters, Au nanoclusters, Pt nanoclusters and CdS nanometer network, etc. [7–10]. Mirkin et al. and Alivisator et al. have done pioneering studies on gold and CdS nanopar- ticles using DNA base-pairing principle [11,12]. Sastry et al. have reported the electrostatic assembly of lysine-packed gold DNA-inspired linear or cluster superstructures and Torimoto group described the electrostatic assembly of CdS nanocrystal chains along with DNA strand templates [13–15]. These strategies have advantages and disadvantages relying on the targeted nanoparticle-based components. A 0039-9140/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2005.05.024