title: Thermodynamically controlled separation of polyvalent 2-nm gold nanoparticle-oligonucleotide conjugates.
abstract: We describe the synthesis of small (2-nm diameter) gold nanoparticles densely functionalized with thiolated DNA (DNA-Au NPs) and a method to separate these particles from excess free DNA after synthesis. The separation method utilizes the thermodynamically enhanced binding properties of 2-nm DNA-Au NPs, compared to free excess DNA, to selectively hybridize these small particles to larger (15-nm diameter) DNA-Au NPs and form aggregates that can be isolated by simple centrifugation. These 2-nm DNA-Au NPs are obtained in a 46% overall yield, have a high surface coverage of DNA (64.8 +/- 6.4 pmol/cm2), and as a result, exhibit increased melting temperatures and cooperative melting properties.
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
authors: Jae-Seung
authors: JS
authors: Lee
authors: Dwight S
authors: DS
authors: Seferos
authors: David A
authors: DA
authors: Giljohann
authors: Chad A
authors: CA
authors: Mirkin
mesh_terms: D015342:DNA Probes / Q000138:chemical synthesis*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009841:Oligonucleotides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D015342:DNA Probes; D009841:Oligonucleotides; D009942:Organometallic Compounds; D006046:Gold