DNA-Based Assembly of Gold Nanocrystals

Loweth, Colin J.; Caldwell, W. Brett; Peng, Xiaogang; Alivisatos, A. Paul; Schultz, Peter G.

doi:10.1002/(sici)1521-3773(19990614)38:12<1808::aid-anie1808>3.3.co;2-3

Cited by 347 publications

(502 citation statements)

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“…It is of interest for nanoconstruction to isolate nanocrystals containing precise numbers of single strands of DNA. 26 Such a counting has been performed for gold colloids 36 and it would constitute an important technology for semiconductor nanocrystals, too. Silanized nanocrystal bands can be sharpened by electrophoresis as shown in Fig.7c.…”

Section: Surface Characterizationmentioning

confidence: 99%

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

et al. 2001

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We describe the synthesis of water-soluble semiconductor nanoparticles, and discuss and characterize their properties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embedded in a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFM indicates that the siloxane shell is 1-5 nm thick yielding final particle sizes of 6-17 nm, depending on the initial CdSe core size. The silica coating does not significantly modify the optical properties of the nanocrystals. Their fluorescence emission is about 32-35 nm FWHM, and can be tuned from blue to red with quantum yields up to 18%, mainly determined by the quantum yield of the underlying CdSe/ZnS nanocrystals. Silanized nanocrystals exhibit enhanced photochemical stability over organic fluorophores. They also display high stability in buffers at physiological conditions (>150 mM NaCl). The introduction of functionalized groups onto the siloxane surface would permit the conjugation of the nanocrystals to biological entities. 2 IntroductionRecent progress in wet chemistry has established a robust route towards the synthesis of highly luminescent semiconductor nanocrystals having sizes ranging from 1.5 to 8 nm. 1,2 By judiciously controlling the growth conditions, the size, and even the shape of II-VI nanocrystals can be accurately tailored. 3,4 The ability to control these parameters has a profound impact in materials science since it can be harnessed for engineering assemblies of nanometer scale units with novel characteristics. [5][6][7][8] At this point, the prominent focus has been the optical properties of these semiconductor nanocrystals. They are governed by strong quantum confinement effects and, therefore, are size dependent. 2,9,10 The absorption onset and fluorescence emission shift to larger energy with decreasing size.Moreover, while the absorption spectrum is a continuum from the bandgap into the UV, the emission pattern is narrow, symmetric, and does not depend on the excitation frequency. Several different sizes of nanocrystals can thus be excited simultaneously with a single excitation source, resulting in well-resolved colors of emission. Further passivation of the nanocrystal surface by a thin shell of a higher band gap material does not significantly modify the absorption and emission features but increases the nanoparticle quantum yield up to 50-70%. [11][12][13] The passivation shell also imparts an efficient photochemical stability, so that the photobleaching is reduced, and the number of photons a single nanocrystal can emit dramatically increases. The ability to discriminate many different colors simultaneously under long-term excitation holds great promise for fluorescent labeling technologies, especially in biology. 14,15 In this respect, organic dye molecules suffer from several limiting factors.First, their narrow absorption bands make it difficult to excite several colors with a single 3 excitation source. In addition, due to the large spectral overlaps between t...

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Section: Surface Characterizationmentioning

confidence: 99%

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

et al. 2001

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“…The ability to control the assembly of nanomaterials from welldefined units is a key step that is expected to allow the exploitation of the technological potential of these materials. The use of the hybridisation properties of oligonucleotides is a promising approach [7][8][9][10][11][12]. In this paper branched oligonucleotides with identical arms which may carry biotin (scheme 1) were prepared.…”

Section: Synthesis Of Branched Oligonucleotides Carrying Three Identimentioning

confidence: 99%

Synthesis of Branched Oligonucleotides as Templates for the Assembly of Nanomaterials

Grimau

Iacopino

Aviñó

et al. 2003

Helvetica Chimica Acta

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Branched oligonucleotides with symmetric arms 6-15 which may contain biotin as a second recognition code were prepared. These molecules are designed to be used for the directed assembly of nanomaterials. The branched structure of the desired oligonucleotides was confirmed by mass spectrometry on small branched oliognucleotides, by gel electrophoresis and by hybridization with complementary oligonucleotide-nanoparticle conjugates followed by visualization of the complexes by transmission electron microscopy.

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“…Compared with these 'homo-coupling' nanoreactions, controlling stoichiometry in the 'cross-coupling' of NPs presents different and arguably greater challenges. It was only achieved through the brilliant design and pre-fabrication of NPs with anisotropic surface functionalities (for example, NP with a single DNA molecule) [17][18][19][20][21][22] .…”

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A systems approach towards the stoichiometry-controlled hetero-assembly of nanoparticles

et al. 2010

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A central theme in nanotechnology is to advance the fundamental understanding of nanoscale component assembly, thereby allowing rational structural design that may lead to materials with novel properties and functions. nanoparticles (nPs) are often regarded as 'artificial atoms', but their 'reactions' are not readily controllable. Here, we demonstrate a complete nanoreaction system whereby colloidal nPs are rationally assembled and purified. Two types of functionalized gold nPs (A and B) are bonded to give specific products AB, AB 2 , AB 3 and AB 4 . The stoichiometry control is realized by fine-tuning the charge repulsion among the B-nPs. The products are protected by a polymer, which allows their isolation in high purity. The integration of hetero-assembly, stoichiometry control, protection scheme and separation method may provide a scalable way to fabricate sophisticated nanostructures.

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DNA-Based Assembly of Gold Nanocrystals

Cited by 347 publications

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Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

Synthesis of Branched Oligonucleotides as Templates for the Assembly of Nanomaterials

A systems approach towards the stoichiometry-controlled hetero-assembly of nanoparticles

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