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Cheng Q.,Beihang University | Jiang L.,Beihang University | Tang Z.,CAS National Center for Nanoscience and Technology
Accounts of Chemical Research | Year: 2014

ConspectusNature has inspired researchers to construct structures with ordered layers as candidates for new materials with high mechanical performance. As a prominent example, nacre, also known as mother of pearl, consists of a combination of inorganic plates (aragonite calcium carbonate, 95% by volume) and organic macromolecules (elastic biopolymer, 5% by volume) and shows a unique combination of strength and toughness. Investigations of its structure reveal that the hexagonal platelets of calcium carbonate and the amorphous biopolymer are alternatively assembled into the orderly layered structure. The delicate interface between the calcium carbonate and the biopolymer is well defined. Both the building blocks that make up these assembled layers and the interfaces between the inorganic and organic components contribute to the excellent mechanical property of natural nacre.In this Account, we summarize recent research from our group and from others on the design of bioinspired materials composed by layering various primitive materials. We focus particular attention on nanoscale carbon materials. Using several examples, we describe how the use of different combinations of layered materials leads to particular properties. Flattened double-walled carbon nanotubes (FDWCNTs) covalently cross-linked in a thermoset three-dimensional (3D) network produced the materials with the highest strength. The stiffest layered materials were generated from borate orthoester covalent bonding between adjacent graphene oxide (GO) nanosheets, and the toughest layered materials were fabricated with Al2O3 platelets and chitosan via hydrogen bonding. These new building blocks, such as FDWCNTs and GO, and the replication of the elaborate micro-/nanoscale interface of natural nacre have provided many options for developing new high performance artificial materials.The interface designs for bioinspired layered materials are generally categorized into (1) hydrogen bonding, (2) ionic bonding, and (3) covalent bonding. Using these different strategies, we can tune the materials to have specific mechanical characteristics such as high strength, excellent strain resistance, or remarkable toughness. Among these design strategies, hydrogen bonding affords soft interfaces between the inorganic plates and the organic matrix. Covalent cross-linking forms chemical bonds between the inorganic plates and the organic matrix, leading to much stronger interfaces. The interfaces formed by ionic bonding are stronger than those formed by hydrogen bonding but weaker than those formed by covalent bonding. © 2014 American Chemical Society.

Wang J.,Beihang University | Cheng Q.,Beihang University | Tang Z.,CAS National Center for Nanoscience and Technology
Chemical Society Reviews | Year: 2012

Nacre (mother-of-pearl), made of inorganic and organic constituents (95 vol% aragonite calcium carbonate (CaCO 3) platelets and 5 vol% elastic biopolymers), possesses a unique combination of remarkable strength and toughness, which is compatible for conventional high performance materials. The excellent mechanical properties are related to its hierarchical structure and precisely designed organic-inorganic interface. The rational design of aragonite platelet strength, aspect ratio of aragonite platelets, and interface strength ensures that the strength of nacre is maximized under platelet pull-out failure mode. At the same time, the synergy of strain hardening mechanisms acting over multiple scales results in platelets sliding on one another, and thus maximizes the energy dissipation of viscoplastic biopolymers. The excellent integrated mechanical properties with hierarchical structure have inspired chemists and materials scientists to develop biomimetic strategies for artificial nacre materials. This critical review presents a broad overview of the state-of-the-art work on the preparation of layered organic-inorganic nanocomposites inspired by nacre, in particular, the advantages and disadvantages of various biomimetic strategies. Discussion is focused on the effect of the layered structure, interface, and component loading on strength and toughness of nacre-mimic layered nanocomposites (148 references). © 2012 The Royal Society of Chemistry.

Zhang W.,CAS National Center for Nanoscience and Technology
Nanoscale | Year: 2011

Gd@C(82)(OH)(22), a water-soluble endohedral metallofullerene derivative, has been proven to possess significant antineoplastic activity in mice. Toxicity studies of the nanoparticle have shown some evidence of low or non toxicity in mice and cell models. Here we employed Caenorhabditis elegans (C. elegans) as a model organism to further evaluate the short- and long-term toxicity of Gd@C(82)(OH)(22) and possible behavior changes under normal and stress culture conditions. With treatment of Gd@C(82)(OH)(22) at 0.01, 0.1, 1.0 and 10 μg ml(-1) within one generation (short-term), C. elegans showed no significant decrease in longevity or thermotolerance compared to the controls. Furthermore, when Gd@C(82)(OH)(22) treatment was extended up to six generations (long-term), non-toxic effects to the nematodes were found. In addition, data from body length measurement, feeding rate and egg-laying assays with short-term treatment demonstrated that the nanoparticles have no significant impact on the individual growth, feeding behavior and reproductive ability, respectively. In summary, this work has shown that Gd@C(82)(OH)(22) is tolerated well by worms and it has no apparent toxic effects on longevity, stress resistance, growth and behaviors that were observed in both adult and young worms. Our work lays the foundations for further developments of this anti-neoplastic agent for clinical applications.

Sun J.,CAS National Center for Nanoscience and Technology
Lab on a chip | Year: 2012

This work reports on a passive double spiral microfluidic device allowing rapid and label-free tumor cell separation and enrichment from diluted peripheral whole blood, by exploiting the size-dependent hydrodynamic forces. A numerical model is developed to simulate the Dean flow inside the curved geometry and to track the particle/cell trajectories, which is validated against the experimental observations and serves as a theoretical foundation for optimizing the operating conditions. Results from separating tumor cells (MCF-7 and Hela) spiked into whole blood indicate that 92.28% of blood cells and 96.77% of tumor cells are collected at the inner and the middle outlet, respectively, with 88.5% tumor recovery rate at a throughput of 3.33 × 10(7) cells min(-1). We expect that this label-free microfluidic platform, driven by purely hydrodynamic forces, would have an impact on fundamental and clinical studies of circulating tumor cells.

Wang Z.-G.,CAS National Center for Nanoscience and Technology | Ding B.,CAS National Center for Nanoscience and Technology
Accounts of Chemical Research | Year: 2014

ConspectusDNA is a well-known natural molecule that carries genetic information. In recent decades, DNA has been used beyond its genetic role as a building block for the construction of engineering materials. Many strategies, such as tile assembly, scaffolded origami and DNA bricks, have been developed to design and produce 1D, 2D, and 3D architectures with sophisticated morphologies. Moreover, the spatial addressability of DNA nanostructures and sequence-dependent recognition enable functional elements to be precisely positioned and allow for the control of chemical and biochemical processes.The spatial arrangement of heterogeneous components using DNA nanostructures as the templates will aid in the fabrication of functional materials that are difficult to produce using other methods and can address scientific and technical challenges in interdisciplinary research. For example, plasmonic nanoparticles can be assembled into well-defined configurations with high resolution limit while exhibiting desirable collective behaviors, such as near-field enhancement. Conducting metallic or polymer patterns can be synthesized site-specifically on DNA nanostructures to form various controllable geometries, which could be used for electronic nanodevices. Biomolecules can be arranged into organized networks to perform programmable biological functionalities, such as distance-dependent enzyme-cascade activities. DNA nanostructures can carry multiple cytoactive molecules and cell-targeting groups simultaneously to address medical issues such as targeted therapy and combined administration. In this Account, we describe recent advances in the functionalization of DNA nanostructures in different fashions based on our research efforts in nanophotonics, nanoelectronics, and nanomedicine. We show that DNA origami nanostructures can guide the assembly of achiral, spherical, metallic nanoparticles into nature-mimicking chiral geometries through hybridization between complementary DNA strands on the surface of nanoparticles and DNA scaffolds, to generate circular dichroism (CD) response in the visible light region. We also show that DNA nanostructures, on which a HRP-mimicking DNAzyme acts as the catalyst, can direct the site-selective growth of conductive polymer nanomaterials with template configuration-dependent doping behaviors. We demonstrate that DNA origami nanostructures can act as an anticancer-drug carrier, loading drug through intercalation, and can effectively circumvent the drug resistance of cultured cancer cells. Finally, we show a label-free strategy for probing the location and stability of DNA origami nanocarriers in cellular environments by docking turn-off fluorescence dyes in DNA double helices. These functionalizations require further improvement and expansion for realistic applications. We discuss the future opportunities and challenges of DNA based assemblies. We expect that DNA nanostructures as engineering materials will stimulate the development of multidisciplinary and interdisciplinary research. © 2014 American Chemical Society.

Li G.,CAS National Center for Nanoscience and Technology | Tang Z.,CAS National Center for Nanoscience and Technology
Nanoscale | Year: 2014

Controllable integration of noble metals (e.g., Au, Ag, Pt, and Pd) and metal oxides (e.g., TiO2, CeO2, and ZrO2) into single nanostructures has attracted immense research interest in heterogeneous catalysis, because they not only combine the properties of both noble metals and metal oxides, but also bring unique collective and synergetic functions in comparison with single-component materials. Among many strategies recently developed, one of the most efficient ways is to encapsulate and protect individual noble metal nanoparticles by a metal oxide shell of a certain thickness to generate the core-shell or yolk-shell structure, which exhibits enhanced catalytic performance compared with conventional supported catalysts. In this review article, we summarize the state-of-the art progress in synthesis and catalytic application of noble metal nanoparticle@metal oxide core/yolk-shell nanostructures. We hope that this review will help the readers to obtain better insight into the design and application of well-defined nanocomposites in both the energy and environmental fields. © the Partner Organisations 2014.

Sun J.,CAS National Center for Nanoscience and Technology | Xianyu Y.,CAS National Center for Nanoscience and Technology | Jiang X.,CAS National Center for Nanoscience and Technology
Chemical Society Reviews | Year: 2014

One of the goals of point-of-care (POC) is a chip-based, miniaturized, portable, self-containing system that allows the assay of proteins, nucleic acids, and cells in complex samples. The integration of nanomaterials and microfluidics can help achieve this goal. This tutorial review outlines the mechanism of assaying biomarkers by gold nanoparticles (AuNPs), and the implementation of AuNPs for microfluidic POC devices. In line with this, we discuss some recent advances in AuNP-coupled microfluidic sensors with enhanced performance. Portable and automated instruments for device operation and signal readout are also included for practical applications of these AuNP-combined microfluidic chips. © The Royal Society of Chemistry 2014.

Gong J.-R.,CAS National Center for Nanoscience and Technology
Small | Year: 2010

Streaming dielectrophoresis and the corresponding electrostatic contribution to binding affinity after application of an AC electric field push the detection limit of an integrated nanoelectronic and electrokinetic device down to the attomolar level. The mechanism works for devices modified with an antibody for antigen detection and with cellular receptors for toxin screening. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu Y.,CAS National Center for Nanoscience and Technology | Tang Z.,CAS National Center for Nanoscience and Technology
Advanced Materials | Year: 2013

Controllable integration of inorganic nanoparticles (NPs) and metal-organic frameworks (MOFs) is leading to the creation of many new multifunctional materials. In this Research News, an emerging type of core-shell nanostructure, in which the inorganic NP cores are encapsulated by the MOF shells, is briefly introduced. Unique functions originating from the property synergies of different types of inorganic NP cores and MOF shells are highlighted, and insight into their future development is suggested. It is highly expected that this Research News could arouse research enthusiasm on such NP@MOF core-shell nanostructures, which have great application potential in devices, energy, the environment, and medicine. Controllable integration of inorganic nanoparticles (NPs) and metal-organic frameworks (MOFs) is creating many new multi-functional materials. In this Research News, an emerging type of core-shell nanostructure, in which NP cores are encapsulated by MOF shells, is briefly introduced. The unique functions originating from property synergies of different types of NPs and MOFs are highlighted, and insights into their future development are offered. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo B.,CAS National Center for Nanoscience and Technology | Zhi L.,CAS National Center for Nanoscience and Technology
Energy and Environmental Science | Year: 2015

Three dimensional graphene-based composites (3DGCs) have attracted significant attention for lithium ion battery applications due to their unique structures and attractive properties. A large number of 3DGCs with novel structures and functions have been developed in the past few years. This review summarizes the current progress of 3DGCs, including their preparation and application in lithium ion batteries, especially from the viewpoint of structural and interfacial engineering, which have attracted more and more attention for the development of high performance electrode systems. © 2015 The Royal Society of Chemistry.

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