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Journal ArticleDOI

Graphene Oxide/Nucleic-Acid-Stabilized Silver Nanoclusters: Functional Hybrid Materials for Optical Aptamer Sensing and Multiplexed Analysis of Pathogenic DNAs

01 Aug 2013-Journal of the American Chemical Society (American Chemical Society)-Vol. 135, Iss: 32, pp 11832-11839
TL;DR: Hybrid systems consisting of nucleic-acid-functionalized silver nanoclusters (AgNCs) and graphene oxide (GO) are used for the development of fluorescent DNA sensors and aptasensors and for the multiplexed analysis of a series of genes of infectious pathogens.
Abstract: Hybrid systems consisting of nucleic-acid-functionalized silver nanoclusters (AgNCs) and graphene oxide (GO) are used for the development of fluorescent DNA sensors and aptasensors, and for the multiplexed analysis of a series of genes of infectious pathogens. Two types of nucleic-acid-stabilized AgNCs are used: one type includes the red-emitting AgNCs (616 nm) and the second type is near-infrared-emitting AgNCs (775 nm). Whereas the nucleic-acid-stabilized AgNCs do not bind to GO, the conjugation of single-stranded nucleic acid to the DNA-stabilized AgNCs leads to the adsorption of the hybrid nanostructures to GO and to the fluorescence quenching of the AgNCs. By the conjugation of oligonucleotide sequences acting as probes for target genes, or as aptamer sequences, to the nucleic-acid-protected AgNCs, the desorption of the probe/nucleic-acid-stabilized AgNCs from GO through the formation of duplex DNA structures or aptamer–substrate complexes leads to the generation of fluorescence as a readout signal f...
Citations
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Journal ArticleDOI
TL;DR: A comprehensive review of the COF field is targeted, providing a historic overview of the chemistry, the advances in the topology design and synthetic reactions, illustrate the structural features and diversities, and scrutinize the development and potential of various functions through elucidating structure-function correlations.
Abstract: Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with permanent porosity and highly ordered structures. Unlike other polymers, a significant feature of COFs is that they are structurally predesignable, synthetically controllable, and functionally manageable. In principle, the topological design diagram offers geometric guidance for the structural tiling of extended porous polygons, and the polycondensation reactions provide synthetic ways to construct the predesigned primary and high-order structures. Progress over the past decade in the chemistry of these two aspects undoubtedly established the base of the COF field. By virtue of the availability of organic units and the diversity of topologies and linkages, COFs have emerged as a new field of organic materials that offer a powerful molecular platform for complex structural design and tailor-made functional development. Here we target a comprehensive review of the COF field, provide a historic overview of the chemistry of the COF field, survey the advances in the topology design and synthetic reactions, illustrate the structural features and diversities, scrutinize the development and potential of various functions through elucidating structure-function correlations based on interactions with photons, electrons, holes, spins, ions, and molecules, discuss the key fundamental and challenging issues that need to be addressed, and predict the future directions from chemistry, physics, and materials perspectives.

1,447 citations

Journal ArticleDOI
TL;DR: In this paper, the authors focus on recent advances in controllable synthesis strategies, chemical and optical properties, and sensing and imaging applications of metal nanoclusters (mainly including Au, Ag, Cu, etc.).

789 citations

Journal ArticleDOI
TL;DR: The rapidly growing interest in metal nanocluster-based theranostic applications will certainly not only fuel the excitement and stimulate research in this highly active field, but also inspire broader concerns across various disciplines.
Abstract: Metal nanoclusters, composed of several to a few hundred metal atoms, have received worldwide attention due to their extraordinary physical and chemical characteristics. Recently, great efforts have been devoted to the exploration of the potential diagnostic and therapeutic applications of metal nanoclusters. Here we focus on the recent advances and new horizons in this area, and introduce the rising progress on the use of metal nanoclusters for biological analysis, biological imaging, therapeutic applications, DNA assembly and logic gate construction, enzyme mimic catalysis, as well as thermometers and pH meters. Furthermore, the future challenges in the construction of biofunctional metal nanoclusters for diagnostic and therapeutic applications are also discussed. We expect that the rapidly growing interest in metal nanocluster-based theranostic applications will certainly not only fuel the excitement and stimulate research in this highly active field, but also inspire broader concerns across various disciplines.

568 citations

Journal ArticleDOI
TL;DR: Graphene and its oxygenated derivatives, including reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the field of biosensors as discussed by the authors, and the discovery of graphene has spectacularly accelerated research on fabricating low-cost electrode materials because of its unique physical properties, including high specific surface area, high carrier mobility, high electrical conductivity, flexibility.
Abstract: Biosensors with high sensitivity, selectivity and a low limit of detection, reaching nano/picomolar concentrations of biomolecules, are important to the medical sciences and healthcare industry for evaluating physiological and metabolic parameters. Over the last decade, different nanomaterials have been exploited to design highly efficient biosensors for the detection of analyte biomolecules. The discovery of graphene has spectacularly accelerated research on fabricating low-cost electrode materials because of its unique physical properties, including high specific surface area, high carrier mobility, high electrical conductivity, flexibility, and optical transparency. Graphene and its oxygenated derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the field of biosensors. The presence of oxygenated functional groups makes GO nanosheets strongly hydrophilic, facilitating chemical functionalization. Graphene, GO and rGO nanosheets can be easily combined with various types of inorganic nanoparticles, including metals, metal oxides, semiconducting nanoparticles, quantum dots, organic polymers and biomolecules, to create a diverse range of graphene-based nanocomposites with enhanced sensitivity for biosensor applications. This review summarizes the advances in two-dimensional (2D) and three-dimensional (3D) graphene-based nanocomposites as emerging electrochemical and fluorescent biosensing platforms for the detection of a wide range of biomolecules with enhanced sensitivity, selectivity and a low limit of detection. The biofunctionalization and nanocomposite formation processes of graphene-based materials and their unique properties, surface functionalization, enzyme immobilization strategies, covalent immobilization, physical adsorption, biointeractions and direct electron transfer (DET) processes are discussed in connection with the design and fabrication of biosensors. The enzymatic and nonenzymatic reactions on graphene-based nanocomposite surfaces for glucose- and cholesterol-related electrochemical biosensors are analyzed. This review covers a very broad range of graphene-based electrochemical and fluorescent biosensors for the detection of glucose, cholesterol, hydrogen peroxide (H2O2), nucleic acids (DNA/RNA), genes, enzymes, cofactors nicotinamide adenine dinucleotide (NADH) and adenosine triphosphate (ATP), dopamine (DA), ascorbic acid (AA), uric acid (UA), cancer biomarkers, pathogenic microorganisms, food toxins, toxic heavy metal ions, mycotoxins, and pesticides. The sensitivity and selectivity of graphene-based electrochemical and fluorescent biosensors are also examined with respect to interfering analytes present in biological systems. Finally, the future outlook for the development of graphene based biosensing technology is outlined.

454 citations

References
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Journal ArticleDOI
22 Jul 2010-ACS Nano
TL;DR: An improved method for the preparation of graphene oxide (GO) is described, finding that excluding the NaNO(3), increasing the amount of KMnO(4), and performing the reaction in a 9:1 mixture of H(2)SO(4)/H(3)PO(4) improves the efficiency of the oxidation process.
Abstract: An improved method for the preparation of graphene oxide (GO) is described. Currently, Hummers’ method (KMnO4, NaNO3, H2SO4) is the most common method used for preparing graphene oxide. We have found that excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. This improved method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or Hummers’ method with additional KMnO4. Moreover, even though the GO produced by our method is more oxidized than that prepared by Hummers’ method, when both are reduced in the same chamber with hydrazine, chemically converted graphene (CCG) produced from this new method is equivalent in its electrical conductivity. In contrast to Hummers’ method, the new method does not generate toxic gas and the temperature is easily controlled. This improved synthesis of GO may be important for large-scale production of GO as well as the ...

9,812 citations

Journal ArticleDOI
TL;DR: This Review highlights the recent advances in optical properties of chemically derived GO, as well as new physical and biological applications that are attracting chemists for its own characteristics.
Abstract: Chemically derived graphene oxide (GO) is an atomically thin sheet of graphite that has traditionally served as a precursor for graphene, but is increasingly attracting chemists for its own characteristics. It is covalently decorated with oxygen-containing functional groups - either on the basal plane or at the edges - so that it contains a mixture of sp(2)- and sp(3)-hybridized carbon atoms. In particular, manipulation of the size, shape and relative fraction of the sp(2)-hybridized domains of GO by reduction chemistry provides opportunities for tailoring its optoelectronic properties. For example, as-synthesized GO is insulating but controlled deoxidation leads to an electrically and optically active material that is transparent and conducting. Furthermore, in contrast to pure graphene, GO is fluorescent over a broad range of wavelengths, owing to its heterogeneous electronic structure. In this Review, we highlight the recent advances in optical properties of chemically derived GO, as well as new physical and biological applications.

2,937 citations

Journal ArticleDOI
Chun-Hua Lu1, Huanghao Yang1, Chun-Ling Zhu, Xi Chen1, Guo-Nan Chen1 
TL;DR: Graphene oxide (GO) is used as a platform for the sensitive and selective detection of DNA and proteins and the interaction of GO and dye-labeled single-stranded DNA leads to quenching of the dye fluorescence.
Abstract: Sensitive platform: The use of graphene oxide (GO) as a platform for the sensitive and selective detection of DNA and proteins is presented. The interaction of GO and dye-labeled single-stranded DNA leads to quenching of the dye fluorescence. Conversely, the presence of a target DNA or protein leads to the binding of the dye-labeled DNA and target, releasing the DNA from GO, thereby restoring the dye fluorescence (see picture).

2,008 citations

Journal ArticleDOI
05 Oct 2001-Science
TL;DR: The differential reflectivity of adjacent stripes enables identification of the striping patterns by conventional light microscopy, and this readout mechanism does not interfere with the use of fluorescence for detection of analytes bound to particles by affinity capture, as demonstrated by DNA and protein bioassays.
Abstract: We synthesized multimetal microrods intrinsically encoded with submicrometer stripes. Complex striping patterns are readily prepared by sequential electrochemical deposition of metal ions into templates with uniformly sized pores. The differential reflectivity of adjacent stripes enables identification of the striping patterns by conventional light microscopy. This readout mechanism does not interfere with the use of fluorescence for detection of analytes bound to particles by affinity capture, as demonstrated by DNA and protein bioassays.

1,259 citations