Conjugates between metal (silver and gold) nanoparticles (NP) and parallel stranded G-quadruplexes (G4-DNA) or double stranded PNA-DNA hybrids have been synthesized. A mixture of DNA-NP conjugates containing discrete number of nanoparticles was prepared by incubation of the DNA (DNA-PNA) functionalized with phosphorothioate residues on both sides of the molecule with equimolar concentrations of NPs. Conjugates containing two particles were efficiently separated from single particles, and nanoparticle trimers and chains of nanoparticles by gel electrophoresis. The molecular morphology of purified NP-G4-DNA [1] and NP-PNA-DNA dimers was confirmed by TEM. The spectroscopic analysis showed the presence of plasmon-mediated interparticle interactions in the above dimers. We have also reported the synthesis of stable phosphorothioate oligonucleotides- coated gold nanoparticles (Au-NPs) that can be bound to metal surfaces and bare NPs, “sticky particles”. The sticky particles were formed during 2-3 hours incubation of 15 nm citrate-protected NPs with great (more than 100-fold) excess of 20 tetrad G4-DNA molecules functionalized with 5 phosphorothioate residues on either sides. The nanoparticles do not aggregate for months and can tolerate salt concentration as high as 200 mM [2]. The phosphorothioate residues located on their surface of sticky particles can anchor them to non-coated NPs. Incubation of 20-fold excess sticky particles with of non-coated Au-NPs yields flower-shaped structures [2] comprising a central non-coated particle and five-six sticky ones at the periphery (see Fig.). The absorption band of the structures is shifted towards long wavelengths compared to the band of individual particles indicating for plasmon coupling between closely-spaced interacting particles in the “flower”. [1] I. Lubitz and A. Kotlyar, Bioconjug. Chem. 22, 482 (2011). [2] I. Lubitz and A. Kotlyar, Bioconjug. Chem. 22, 2043 (2011).

Discrete Conjugates of Nanoparticles with G4-DNA and PNA-DNA Hybrids for Plasmonic and Nanoelectronic Applications / A. Kotlyar, G. Eidelshtein, I. Lubitz, M. Anzola, C. Giannini. ((Intervento presentato al 1. convegno International Conference on Self Assembly and Molecular Electronics tenutosi a Aalborg (Danmark) nel 2012.

Discrete Conjugates of Nanoparticles with G4-DNA and PNA-DNA Hybrids for Plasmonic and Nanoelectronic Applications

C. Giannini
Ultimo
2012

Abstract

Conjugates between metal (silver and gold) nanoparticles (NP) and parallel stranded G-quadruplexes (G4-DNA) or double stranded PNA-DNA hybrids have been synthesized. A mixture of DNA-NP conjugates containing discrete number of nanoparticles was prepared by incubation of the DNA (DNA-PNA) functionalized with phosphorothioate residues on both sides of the molecule with equimolar concentrations of NPs. Conjugates containing two particles were efficiently separated from single particles, and nanoparticle trimers and chains of nanoparticles by gel electrophoresis. The molecular morphology of purified NP-G4-DNA [1] and NP-PNA-DNA dimers was confirmed by TEM. The spectroscopic analysis showed the presence of plasmon-mediated interparticle interactions in the above dimers. We have also reported the synthesis of stable phosphorothioate oligonucleotides- coated gold nanoparticles (Au-NPs) that can be bound to metal surfaces and bare NPs, “sticky particles”. The sticky particles were formed during 2-3 hours incubation of 15 nm citrate-protected NPs with great (more than 100-fold) excess of 20 tetrad G4-DNA molecules functionalized with 5 phosphorothioate residues on either sides. The nanoparticles do not aggregate for months and can tolerate salt concentration as high as 200 mM [2]. The phosphorothioate residues located on their surface of sticky particles can anchor them to non-coated NPs. Incubation of 20-fold excess sticky particles with of non-coated Au-NPs yields flower-shaped structures [2] comprising a central non-coated particle and five-six sticky ones at the periphery (see Fig.). The absorption band of the structures is shifted towards long wavelengths compared to the band of individual particles indicating for plasmon coupling between closely-spaced interacting particles in the “flower”. [1] I. Lubitz and A. Kotlyar, Bioconjug. Chem. 22, 482 (2011). [2] I. Lubitz and A. Kotlyar, Bioconjug. Chem. 22, 2043 (2011).
2012
Settore CHIM/02 - Chimica Fisica
Settore CHIM/06 - Chimica Organica
Discrete Conjugates of Nanoparticles with G4-DNA and PNA-DNA Hybrids for Plasmonic and Nanoelectronic Applications / A. Kotlyar, G. Eidelshtein, I. Lubitz, M. Anzola, C. Giannini. ((Intervento presentato al 1. convegno International Conference on Self Assembly and Molecular Electronics tenutosi a Aalborg (Danmark) nel 2012.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/223078
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