Oligonucleotide-based Theorem Proving by Cross-Linking Gold Nanoparticle Assembly Park, Ji-Yoon

March 23, 2004 APRL 2 Colloidal Gold  Diameter: 5-20 nm  SPR (Surface plasmon resonance): 520 nm optical obsorption peak  Aggregation (>520 nm: shift the absorption peak)  Cross-linking mechanism by target DNA between the gold particle  Application: DNA, lectin, heavy metal ion, potassium ion, protein A

March 23, 2004 APRL 3 The DNA-based Nanoparticle Assembly Strategy 15 mer 45 mer

March 23, 2004 APRL 4 Purpose In this paper, we purpose to assembly of DNA-functionalized gold nanoparticles as optical detection approach. Oligonucleotides offer several advantages over non-biological-based linker molecules. –Various sizes of gold nanoparticles are readily available at low cost, surface modification with probe DNA is easier, and the temperature control for the formation of nanoparticles is not necessary.

March 23, 2004 APRL 5 The Target Problem R is true !! nil, add R as

March 23, 2004 APRL 6 Experimental Section Preparation of Au Nanoparticles Synthesis and Purification of (Alkanethiol)-Modified Oligonucleotides Preparation of 3'- or 5'-(Alkanethiol)oligonucleotide-Modified Au Nanoparticles Preparation and Characterization of Linker DNA Preparation and Characterization of DNA-Linked Au Nanoparticle Aggregates Transmission Electron Microscopy (TEM) Calculations of UV-vis Exinction Spectra

March 23, 2004 APRL 7 PrimerSequence(5’ → 3’)LengthModification GC Content ( % ) ST¬Q AAG CAG TAG CGA CCA ATT GAC GCA AAT TGA CGT ACG TAC GCT GAA 45 merNone46.7 ¬RPQ CAT ACA ATG AAC GCA GTC AAC GCA AGG CAG TTC AGC GTA CGT ACG 45 merNone51.1 ¬P CTG CCT TGC GTT GAC 15 mer 5’-phosphate60.0 R TGC GTT CAT TGT ATG 15 mer 3’-thiol40.0 ¬S TGG TCG CTA CTT 15 mer 3’-thiol53.3 ¬T TCA ATT TGC GTC AAT 15 mer 5’-phosphate33.3 The Sequence Information

March 23, 2004 APRL nm Comparison between Before and After Hybridization

March 23, 2004 APRL 9 (A) The UV-vis spectrum of oligonucleotide-modified 10-nm particles before (red line) and after (blue line) DNA-induced assembly (B) Solutions of 10-nm-diameter Au particles before (cuvette A) and after (cuvette B) DNA-induced assembly (C) Aqueous solution of 10-nm-diameter Au particles before (red) and after (blue) the addition of NaCl. This is an irreversible process (A)(B)(C)

March 23, 2004 APRL 10 Concentration Variation of 10 nm Colloidal Gold

March 23, 2004 APRL 11 Conclusions A new “programmed assembly” strategy for organizing nanoparticles into periodic functional materials The strategy utilize nanoparticle building blocks modified with alkanethiol- capped oligonucleotides and complementary linker oligonucleotide strands to form extended structures with control over particle chemical composition, periodicity, and aggregated thermal stability Highly selective diagnostic method relies on the distance-dependent optical properties of gold particles