Supraparticles are self-limiting nanoparticle ensembles with attractive properties from their unique hierarchical (primary and secondary) structures. Aiming at relieving the bottleneck of the very limited material building blocks in DNA nanotechnology, we herein demonstrate Pt-based supraparticles as catalytic materials for valence-controllable and high density DNA functionalizations toward DNA-programmed nanoassembly.

AbstractWireframe, polyhedral, supramolecular complexes made of DNA have uniform sizes, defined three-dimensional shapes, porous facets, hollow interiors, good biocompatibilities, and chemical functionalizability. They confer great potentials in bottom-up nanoengineering towards various applications. In this review, we summarize recent advances in the rational design and programmed assembly of DNA wireframe polyhedra. Their assembly is based on three distinctively different strategies: individual strands-based assembly, tile-based assembly, and scaffolded DNA origami. Applications of these polyhedral structures in templated nanomaterial assembly and in-vivo cargo delivery are discussed. In the future, expanding the structural complexity and exploring their applications, especially in nanomaterials science and biomedicines, should be a primary focus of this rapidly developing and evolving activity of structural DNA nanotechnology.

We report a rationally designed electrocatalyst with high activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) based on a nanocarbon-intercalated graphene (CIG) material doped with nitrogen (N) and iron (Fe) (Fe–N-CIG). This easily made novel 3D Fe–N-CIG catalyst exhibits a surprisingly high ORR and OER activity and stability, making it a new noble-metal-free bifunctional catalyst for future applications in regenerative energy conversion systems.

Noble metal nanoparticle oligomers are important in applications including plasmonics, catalysis, and molecular sensing. These nanostructural units featuring abundant inter-particle junctions are helpful for a physical/chemical understanding of structure-activity relationships of self-assembled metamaterials. A simple, rapid, and potentially general strategy for the preparation of monodisperse nanoparticle clusters in a homogeneous solution is highly desired for fundamental research toward liquid metamaterials and chemical/biological applications, but this is however very challenging. Here we report an Ag+ soldering strategy to prepare strongly coupled plasmonic (Au) and catalytic (Pt, Au@Pd (Au core with a Pd shell)) nanoparticle clusters almost instantly (<1 min) in a solution without special synthetic efforts, complicated surface decorations, or structure-directing templates. The resulting clusters are isolatable by agarose gel electrophoresis, resulting in mechanically stable products in high purity. The optical extinctions of Au nanodimers (the simplest and most basic form of a coupled structure) exhibit prominent longitudinal plasmonic coupling for nanoparticles down to 13.3 nm in diameter. Theoretical simulations attribute the strong coupling to the existence of a sub-nm gap (c.a. 0.76 nm) between soldered particles, suggesting an ideal (stable, soluble, monodisperse, and weakly passivated) substrate for surface enhanced Raman scattering (SERS) applications.

The past years have witnessed a rapid development of DNA nanotechnology in nanomaterials science with a central focus on programmable material construction on the nanoscale. An efficient method is therefore highly desirable (but challenging) for analytical/preparative purification of DNA-conjugated nano-objects and their DNA-assemblies. In this regard, agarose gel electrophoresis, a traditional technique that has been invented for biomacromolecule separation, has found many innovative uses. This includes shape, size, charge, and ligand-valence separations of nanoparticle building blocks as well as monitoring a self-assembly process towards product identification and purification.Agarose gel electrophoresis, a technique originally invented for biomolecule research, has found many innovative applications in DNA nanotechnology towards shape, size, valence, and nanostructured product separations.

Colloidosomes with a hollow interior and a porous plasmonic shell are highly desired for many applications including nanoreactors, surface-enhanced Raman scattering (SERS), photothermal therapy, and controlled drug release. We herein report a silica nanosphere-templated electrostatic self-assembly in conjunction with a newly developed Ag+ soldering to fabricate gold colloidosomes toward multifunctionality and stimuli-responsibility. The gold colloidosomes are capable of capturing a nanosized object and releasing it via structural dissociation upon responding to a biochemical input (GSH, glutathione) at a concentration close to its cellular level. In addition, the colloidosomes have a tunable nanoporous shell composed of strongly coupled gold nanoparticles, which exhibit broadened near-infrared plasmon resonance. These features along with the simplicity and high tunability of the fabrication process make the gold colloidosomes quite promising for applications in a chemical or cellular environment.

DNA nanotechnology offers a massively parallel process to build innovative nanomaterials from the bottom up with excellent structural programmability and functional tunability. So far most of the successes have been restricted to gold nanoparticles (AuNPs) based on an earlier breakthrough in controlling the number (valence) of DNA ligands on an AuNP. However, attempts to incorporate non-gold metal materials have met various difficulties. To address this challenge, we herein develop a method to achieve reliable DNA-conjugations and gel electrophoretic valence separations of Au@Ag and Au@Pd core–shell nanoparticles. The existence of a gold core allows us to control the structure, composition, and colloidal properties of the nanoparticles, which is critical to achieving compatibility with gel electrophoresis. The resulting bionanoconjugates with strictly defined DNA valences function very well in DNA-programmable nanoassembly towards various possible applications in the future.

Silver nanoparticles (AgNPs), which are stable in strongly ionic solutions and appear as a single sharp band during gel electrophoresis, are synthesized by a facile one-pot process, allowing for the first time realization of AgNP–DNA bio-nano-conjugates bearing a discrete number of DNA ligands.

Discrete DNA decorations of Pt nanoparticles (PtNPs) are realized for the first time, which provide a valence control over the quasi-molecular self-assembly of Au-Pt bimetallic heteronanostructures with DNA as the guide.

Eggshell membrane (ESM) has been employed as a unique and especially efficient synthetic platform capable of generating fluorescent silver and gold nanoclusters via various chemical routes. Potential applications of the metal/ESM adducts include recyclable catalysts, sensing paper, surface enhanced Raman scattering interface, fluorescent surface patterning and anti-counterfeiting.

In this communication, we report the preparation of DNA-SWNT hybrid hydrogel which is pH responsive and strength tunable.

The interstrand orientation of a DNA duplex plays a pivotal role in its biological and chemical functions. Therefore, developing an efficient way to determine (control and monitor) the parallel or antiparallel conformation of a DNA duplex is of great significance, which, however, remains a big challenge under some circumstances. In this work, we demonstrate that gold nanoparticles tagged on DNA are especially useful in trapping and detecting a special interstrand orientation of a DNA double helix, based on inherent electrostatic and steric repulsions between nanoparticles which will affect their self-assembly into a large structure. More importantly, some of the conformations revealed by the gold nanoparticle assay may even not be thermodynamically preferred and thus will be hard to detect using currently available methods. This simple, straightforward, and efficient methodology capable of dictating and probing a special DNA duplex structure provides a useful tool for conformational analyses and functional explorations of biomolecules as well as biophysical and nanobiomedical research.

Surface-initiated DNA polymerization has been employed in this work as an appealing signal amplification strategy for electrochemical DNA sensors. This strategy is especially superior in that enzymes, colloidal particles and other bulky structures are not involved in order to achieve amplified signals, and thus is highly promising in circumventing problems due to uncontrolled nucleation, adsorption, aggregation or disassembly of nanoparticles, liposomes and proteins, as well as enzyme deactivations. Our preliminary results have shown that a decrease (as compared to an amplification-free system) in detection limit by a factor greater than 300 can be easily achieved by cyclic voltammetry under still not optimized conditions, with an ability of differentiating a single base mutation.

Nanoparticles that respond to various chemical and physical stimuli form the basis for various conceivable applications including sensors, chemical logic, biomedical imaging, and therapies. In this work, we demonstrate that the electrostatic and chemical (complexing and gold–thiol bonding) interactions existing in a gold nanoparticle/Zn2+/dithiothreitol-based ternary chemical system is “programmable” and can be utilized to regulate the aggregation and dispersion of nanoparticles via XOR and INHIBIT logics. The resulting solutions alter their colors according to different input combinations because of the well-controlled aggregation or dispersion of plasmonic gold nanoparticles, opening up new possibilities for the developments of advanced sensors and nanobiomedical devices based on the coupling, gating, and signaling of different chemical stimuli.

Graphene oxide (GO) can be reduced and decorated by bovine serum albumin (BSA) at suitable pH and temperature. The resulting bioconjugates between BSA and GO or reduced GO are ideal templates for highly efficient assembly of a variety of nanoparticles with dramatically different compositions, sizes, shapes, and properties. This methodology offers a great chance for investigations on the structure−performance relationship of hybrid nanomaterials toward combinatorial material design aiming at special functions and applications.

Non-covalent DNA decorations on the basal planes of graphene oxide and reduced graphene oxide nanosheets are realized. The resulting DNA–carbon bioconjugates (DNA–GO or DNA–RGO) bearing multiple thiol groups tagged on DNA strands are then employed to scaffold the two-dimensional self-assembly of gold nanoparticles (AuNPs) into metal–carbon hybrid nanostructures (namely AuNP–DNA–GO or AuNP–DNA–RGO) that may find important applications in various aspects. The resulting heteronanostructures incorporating metal nanoparticles obtained by self-assembly are highly stable and water-soluble, and can be easily isolated by gel electrophoresis to guarantee high purity. Thanks to the noncovalent features of this method, either GO or RGO do not suffer from any permanent alterations of their structures and properties. In addition, the nanoparticles still maintain their optical absorbance after being assembled, and the assembly process is highly specific. This self-assembly based method for constructing heterostructured materials is excellent at overcoming any incompatibilities between nanoparticle syntheses and the formation of hybrid structures. As a result, this strategy is easily adaptable to various other materials other than gold nanoparticles and also favors the combinatorial assembly of multiple nanophases on a single nanosheet.

Gold nanoparticles (AuNPs) have been employed to design colorimetric visual sensing assays toward the detections of various targets including DNA, based on the aggregation induced color transitions of AuNPs. However, the relatively high detection limit (LOD 10 nM) in the case of DNA detection has become a stumbling block on the road of the further development and applications of these assays. This research aims at overcoming this limit by virtue of a seeded gold reduction strategy. Typically, low concentrations of 13 nm AuNPs modified with suitable DNA probes are allowed to hybridize with a DNA target to form aggregates, which are then transferred into a gold-enhancing cocktail for further depositions of more gold on the initial AuNP seeds. The color of the assay thus sensitively reflects the initial aggregation status of the 13 nm AuNPs, which can be related to the concentrations of the DNA target. This assay has a sensitivity that is at least 25–50 times improved. Under still not fully optimized conditions, 0.4 fmol DNA in a 2 μL sample can be confidently detected with the ability of distinguishing a single base mutation. It does not require isolations of the 13 nm AuNP aggregates during analyses and shares the advantages of a homogeneous assay, including simplicity, adaptability, convenience, and being free of interferences due to non-specific surface adsorptions.

A sensitive and fully DNA-structured ion sensor was built by integrating polyT sequences for highly selective Hg2+ recognitions and two flanking G-quadruplex halves for allosteric signal transductions. The construction of this sensor was very easy that allowed a cost-effective detection of Hg2+ with a limit of detection of 4.5 nM, which was lower than the 10 nM toxic level for drinkable water as regulated by the US's EPA. The strategy employed for the construction of this sensor may be further extended to other sensors through a rational structural fusion between re-engineered aptameric and enzymic DNA sequences.

A simple and cost-effective strategy to prepare Pd nanoparticle decorated glassy carbon electrodes is reported. Mechanically shortened fish sperm DNA molecules were used as effective nucleation templates for the deposition of highly dispersed Pd nanoparticles on glassy carbon electrodes. Atomic force microscopy (AFM) was employed to check the morphologies of as-deposited Pd nanoparticles. Electrocatalytic investigations revealed that the modified electrode using a DNA-based electroless deposition had remarkable catalytic activities toward the reductions of dissolved oxygen and hydrogen peroxide, as well as the oxidation of hydrazine. The DNA-assisted electroless deposition of Pd nanoparticles is expected to offer an easy, quick and low-cost strategy toward applications in fuel cells as well as electrochemical sensors.

Split halves of a hemin-binding DNAzyme have been assembled with an anti-adenosine aptamer to build a homogeneous allosteric sensor for adenosine with high selectivity and sensitivity.

We report a rationally designed electrocatalyst with high activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) based on a nanocarbon-intercalated graphene (CIG) material doped with nitrogen (N) and iron (Fe) (Fe–N-CIG). This easily made novel 3D Fe–N-CIG catalyst exhibits a surprisingly high ORR and OER activity and stability, making it a new noble-metal-free bifunctional catalyst for future applications in regenerative energy conversion systems.

Silver nanoparticles (AgNPs), which are stable in strongly ionic solutions and appear as a single sharp band during gel electrophoresis, are synthesized by a facile one-pot process, allowing for the first time realization of AgNP–DNA bio-nano-conjugates bearing a discrete number of DNA ligands.

Non-covalent DNA decorations on the basal planes of graphene oxide and reduced graphene oxide nanosheets are realized. The resulting DNA–carbon bioconjugates (DNA–GO or DNA–RGO) bearing multiple thiol groups tagged on DNA strands are then employed to scaffold the two-dimensional self-assembly of gold nanoparticles (AuNPs) into metal–carbon hybrid nanostructures (namely AuNP–DNA–GO or AuNP–DNA–RGO) that may find important applications in various aspects. The resulting heteronanostructures incorporating metal nanoparticles obtained by self-assembly are highly stable and water-soluble, and can be easily isolated by gel electrophoresis to guarantee high purity. Thanks to the noncovalent features of this method, either GO or RGO do not suffer from any permanent alterations of their structures and properties. In addition, the nanoparticles still maintain their optical absorbance after being assembled, and the assembly process is highly specific. This self-assembly based method for constructing heterostructured materials is excellent at overcoming any incompatibilities between nanoparticle syntheses and the formation of hybrid structures. As a result, this strategy is easily adaptable to various other materials other than gold nanoparticles and also favors the combinatorial assembly of multiple nanophases on a single nanosheet.

Eggshell membrane (ESM) has been employed as a unique and especially efficient synthetic platform capable of generating fluorescent silver and gold nanoclusters via various chemical routes. Potential applications of the metal/ESM adducts include recyclable catalysts, sensing paper, surface enhanced Raman scattering interface, fluorescent surface patterning and anti-counterfeiting.

DNA nanotechnology offers a massively parallel process to build innovative nanomaterials from the bottom up with excellent structural programmability and functional tunability. So far most of the successes have been restricted to gold nanoparticles (AuNPs) based on an earlier breakthrough in controlling the number (valence) of DNA ligands on an AuNP. However, attempts to incorporate non-gold metal materials have met various difficulties. To address this challenge, we herein develop a method to achieve reliable DNA-conjugations and gel electrophoretic valence separations of Au@Ag and Au@Pd core–shell nanoparticles. The existence of a gold core allows us to control the structure, composition, and colloidal properties of the nanoparticles, which is critical to achieving compatibility with gel electrophoresis. The resulting bionanoconjugates with strictly defined DNA valences function very well in DNA-programmable nanoassembly towards various possible applications in the future.

Split halves of a hemin-binding DNAzyme have been assembled with an anti-adenosine aptamer to build a homogeneous allosteric sensor for adenosine with high selectivity and sensitivity.

In this communication, we report the preparation of DNA-SWNT hybrid hydrogel which is pH responsive and strength tunable.

Discrete DNA decorations of Pt nanoparticles (PtNPs) are realized for the first time, which provide a valence control over the quasi-molecular self-assembly of Au-Pt bimetallic heteronanostructures with DNA as the guide.