DNA‐Decorated,Helically Twisted Nanoribbons: A Scaffold for the Fabrication of One‐Dimensional,Chiral, Plasmonic Nanostructures

Crafting of chiral plasmonic nanostructures is extremely important and challenging. DNA‐directed organization of nanoparticle on a chiral template is the most appealing strategy for this purpose. Herein, we report a supramolecular approach for the design of DNA‐decorated, helically twisted nanoribbons through the amphiphilicity‐driven self‐assembly of a new class of amphiphiles derived from DNA and hexaphenylbenzene (HPB). The ribbons are self‐assembled in a lamellar fashion through the hydrophobic interactions of HPB. The transfer of molecular chirality of ssDNA into the HPB core results in the bias of one of the chiral propeller conformations for HPB and induces a helical twist into the lamellar packing, and leads to the formation of DNA‐wrapped nanoribbons with M‐helicity. The potential of the ribbon to act as a reversible template for the 1D chiral organization of plasmonic nanomaterials through DNA hybridization is demonstrated.     

DNA‐Decorated,Helically Twisted Nanoribbons: A Scaffold for the Fabrication of One‐Dimensional,Chiral, Plasmonic Nanostructures

Crafting of chiral plasmonic nanostructures is extremely important and challenging. DNA‐directed organization of nanoparticle on a chiral template is the most appealing strategy for this purpose. Herein, we report a supramolecular approach for the design of DNA‐decorated, helically twisted nanoribbons through the amphiphilicity‐driven self‐assembly of a new class of amphiphiles derived from DNA and hexaphenylbenzene (HPB). The ribbons are self‐assembled in a lamellar fashion through the hydrophobic interactions of HPB. The transfer of molecular chirality of ssDNA into the HPB core results in the bias of one of the chiral propeller conformations for HPB and induces a helical twist into the lamellar packing, and leads to the formation of DNA‐wrapped nanoribbons with M‐helicity. The potential of the ribbon to act as a reversible template for the 1D chiral organization of plasmonic nanomaterials through DNA hybridization is demonstrated.     

Tuning One‐Dimensional Nanostructures of Bola‐Like Peptide Amphiphiles by Varying the Hydrophilic Amino Acids

By combining experimental measurements and computer simulations, we here show that for the bola‐like peptide amphiphiles XI₄X, where X=K, R, and H, the hydrophilic amino acid substitutions have little effect on the β‐sheet hydrogen‐bonding between peptide backbones. Whereas all of the peptides self‐assemble into one dimensional (1D) nanostructures with completely different morphologies, that is, nanotubes and helical nanoribbons for KI₄K, flat and multilayered nanoribbons for HI₄H, and twisted and bilayered nanoribbons for RI₄R. These different 1D morphologies can be explained by the distinct stacking degrees and modes of the three peptide β‐sheets along the x‐direction (width) and the z‐direction (height), which microscopically originate from the hydrogen‐bonding ability of the sheets to solvent molecules and the pairing of hydrophilic amino acid side chains between β‐sheet monolayers through stacking interactions and hydrogen bonding. These different 1D nanostructures have distinct surface chemistry and functions, with great potential in various applications exploiting the respective properties of these hydrophilic amino acids.     

Ribbon- and boardlike nanostructures of nickel hydroxide: synthesis, characterization, and electrochemical properties

We report the synthesis, characterization, and electrochemistry properties of ribbon- and boardlike nanostructures of nickel hydroxide, which crystallize in different phases. The ribbonlike nanostructures (nanoribbons) of nickel hydroxide were synthesized by treating amorphous alpha-Ni(OH)2 with high concentrations of nickel sulfate. These nanoribbons crystallized in a new phase had typical widths of 5-25 nm, thicknesses of 3-9 nm, and lengths of up to a few micrometers. After further treatment in alkali at 60 degrees C, the nanoribbons converted to boardlike nanostructures (nanoboards), which crystallized in the beta-phase with the average length-width-thickness ratio of 20:6:1. The crystal structures, Raman spectra, and electrochemical properties of these nanostructures of nickel hydroxide are described in this paper. For comparison, the amorphous alpha-Ni(OH)2 has also been investigated. Moreover, the intermediate product between the nanoribbons and the nanoboards displays a unique structure, which implied an interesting transformation process. The nanoribbons with the new phase show some unique features in Raman spectra, two new peaks located at 3534 and 3592 cm(-1) in the OH stretching region, indicating the new chemical environment of the hydroxyl groups. The nanoboards exhibit the highest specific capacity, which is close to the theoretical capacity of beta-Ni(OH)2. It suggests that the boardlike nanostructure is helpful in improving the electrochemical performance of nickel hydroxide. Because of their unique structures and properties, the nanoribbons and nanoboards of nickel hydroxide may give a new perspective for applications in the areas of catalysts and rechargeable batteries.     

Hybrid Soft Nanomaterials Composed of DNA Microspheres and Supramolecular Nanostructures of Semi-artificial Glycopeptides

Aqueous hybrid soft nanomaterials consisting of plural supramolecular architectures with a high degree of segregation (orthogonal coexistence) and precise hierarchy at the nano- and microscales, which are reminiscent of complex biomolecular systems, have attracted increasing attention. Remarkable progress has been witnessed in the construction of DNA nanostructures obtained by rational sequence design and supramolecular nanostructures of peptide derivatives through self-assembly under aqueous conditions. However, orthogonal self-assembly of DNA nanostructures and supramolecular nanostructures of peptide derivatives in a single medium has not yet been explored in detail. In this study, DNA microspheres, which can be obtained from three single-stranded DNAs, and three different supramolecular nanostructures (helical nanofibers, straight nanoribbons, and flowerlike microaggregates) of semi-artificial glycopeptides were simultaneously constructed in a single medium by a simple thermal annealing process, which gives rise to hybrid soft nanomaterials. Fluorescence imaging with selective staining of each supramolecular nanostructure uncovered the orthogonal coexistence of these structures with only marginal impact on their morphology. Additionally, the biostimuli-responsive degradation propensity of each supramolecular architecture is retained, and this may allow the construction of active soft nanomaterials exhibiting intelligent biofunctions.     

On‐Surface Synthesis and Characterization of Triply Fused Porphyrin–Graphene Nanoribbon Hybrids

On‐surface synthesis offers a versatile approach to prepare novel carbon‐based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine‐tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non‐benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on‐surface synthesis of a Por–GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por–GNR hybrid has been characterized by bond‐resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc‐AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV.     

Metal phthalocyanine nanoribbons and nanowires

Nanoribbons and nanowires of different metal phthalocyanines (copper, nickel, iron, cobalt, and zinc), as well as copper hexadecafluorophthalocyanine (F(16)CuPc), have been grown by organic vapor-phase deposition. Their properties, as a function of substrate type, source-to-substrate distance, and substrate temperature, were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and absorption measurements. The size and morphology of the nanostructures were found to be mainly determined by the substrate temperature. The crystal structure was dependent on the substrate temperature as well. At substrate temperatures below 200 degrees C, in addition to straight nanoribbons, twisted nanoribbons were found for all investigated materials except F(16)CuPc, which formed helical nanoribbons upon exposure to an electron beam. The formation of different nanostructures (nanoribbons, twisted nanoribbons, and helical nanoribbons) is discussed.     

Self‐assembly of DNA Origami Using Rolling Circle Amplification Based DNA Nanoribbons

During the development of structural DNA nanotechnology, the emerging of scaffolded DNA origami is marvelous. It utilizes DNA double helix inherent specificity of Watson‐Crick base pairing and structural features to create self‐assembling structures at the nanometer scale exhibiting the addressable character. However, the assembly of DNA origami is disorderly and unpredictable. Herein, we present a novel strategy to assemble the DNA origami using rolling circle amplification based DNA nanoribbons as the linkers. Firstly, long single‐stranded DNA from Rolling Circle Amplification is annealed with several staples to form kinds of DNA nanoribbons with overhangs. Subsequently, the rectangle origami is formed with overhanged staple strands at any edge that would hybridize with the DNA nanoribbons. By mixing them up, we illustrate the one‐dimensional even two‐dimensional assembly of DNA origami with good orientation.     

Catalyst-assisted formation of nanocantilever arrays on ZnS nanoribbons by post-annealing treatment

Nanocantilever arrays were formed on the edges of the +/- (0001) planes of pre-synthesized ZnS nanoribbons via catalyst-assisted post-annealing treatment on Si substrate at 600 degrees C. Similar nanostructures could also be generated when ZnS nanoribbons were annealed by mixing with Si or SiO powder. The formation of nanocantilever arrays is associated with orientation-dependent chemical etching of the +/- (0001) polar surfaces of ZnS nanoribbons. The ability of increasing structural complexity beyond the one-step "thermal evaporation and condensation" synthesis provides a new dimension to the rational design of building blocks for nanodevices.     

In Vitro Selection of pH‐Activated DNA Nanostructures

We report the first in vitro selection of DNA nanostructures that switch their conformation when triggered by change in pH. Previously, most pH‐active nanostructures were designed using known pH‐active motifs, such as the i‐motif or the triplex structure. In contrast, we performed de novo selections starting from a random library and generated nanostructures that can sequester and release Mipomersen, a clinically approved antisense DNA drug, in response to pH change. We demonstrate extraordinary pH‐selectivity, releasing up to 714‐fold more Mipomersen at pH 5.2 compared to pH 7.5. Interestingly, none of our nanostructures showed significant sequence similarity to known pH‐sensitive motifs, suggesting that they may operate via novel structure‐switching mechanisms. We believe our selection scheme is general and could be adopted for generating DNA nanostructures for many applications including drug delivery, sensors and pH‐active surfaces.     

The Rolling‐Up of Oligophenylenes to Nanographenes by a HF‐Zipping Approach

Intramolecular aryl–aryl coupling is the key transformation in the rational synthesis of nanographenes and nanoribbons. In this respect the C−F bond activation was shown to be a versatile alternative enabling the synthesis of several unique carbon‐based nanostructures. Herein we describe an unprecedentedly challenging transformation showing that the C−F bond activation by aluminum oxide allows highly effective domino‐like C−C bond formation. Despite the flexible nature of oligophenylene‐based precursors efficient regioselective zipping to the target nanostructures was achieved. We show that fluorine positions in the precursor structure unambiguously dictate the “running of the zipping‐program” which results in rolling‐up of linear oligophenylene chains around phenyl moieties yielding target nanographenes. The high efficiency of zipping makes this approach attractive for the synthesis of unsubstituted nanographenes which are difficult to obtain in pure form by other methods.     

Self‐Assembly of DNA–Oligo(p‐phenylene‐ethynylene) Hybrid Amphiphiles into Surface‐Engineered Vesicles with Enhanced Emission

Surface‐addressable nanostructures of linearly π‐conjugated molecules play a crucial role in the emerging field of nanoelectronics. Herein, by using DNA as the hydrophilic segment, we demonstrate a solid‐phase “click” chemistry approach for the synthesis of a series of DNA–chromophore hybrid amphiphiles and report their reversible self‐assembly into surface‐engineered vesicles with enhanced emission. DNA‐directed surface addressability of the vesicles was demonstrated through the integration of gold nanoparticles onto the surface of the vesicles by sequence‐specific DNA hybridization. This system could be converted to a supramolecular light‐harvesting antenna by integrating suitable FRET acceptors onto the surface of the nanostructures. The general nature of the synthesis, surface addressability, and biocompatibility of the resulting nanostructures offer great promises for nanoelectronics, energy, and biomedical applications.     

Copper(II)–Thymine Coordination Polymer Nanoribbons as Potential Oligonucleotide Nanocarriers

The direct reaction between copper nitrate, thymine‐1‐acetic acid, and 4,4′‐bipyridine in water leads to the formation of a blue colloid comprising uniform crystalline nanoribbons (length >1 μm; width ca. 150–185 nm; diameter ca. 15–60 nm) of a coordination polymer. The polymer displays a thymine‐based structure freely available for supramolecular interactions. These nanostructures show significant selective interaction with single‐stranded oligonucleotides based on adenine. Remarkably, they present low cell toxicity in three cell lines–despite the copper(II) content–and can be used as nanocarriers of oligonucleotides. These results suggest the potential of these types of nanostructures in several biological applications.     

Highly Ordered Self‐Assembly of Native Proteins into 1D, 2D,and 3D Structures Modulated by the Tether Length of Assembly‐Inducing Ligands

In nature, proteins self‐assemble into various structures with different dimensions. To construct these nanostructures in laboratories, normally proteins with different symmetries are selected. However, most of these approaches are engineering‐intensive and highly dependent on the accuracy of the protein design. Herein, we report that a simple native protein LecA assembles into one‐dimensional nanoribbons and nanowires, two‐dimensional nanosheets, and three‐dimensional layered structures controlled mainly by small‐molecule assembly‐inducing ligands RnG (n =1, 2, 3, 4, 5) with varying numbers of ethylene oxide repeating units. To understand the formation mechanism of the different morphologies controlled by the small‐molecule structure, molecular simulations were performed from microscopic and mesoscopic view, which presented a clear relationship between the molecular structure of the ligands and the assembled patterns. These results introduce an easy strategy to control the assembly structure and dimension, which could shed light on controlled protein assembly.     

Controlled synthesis and photoluminescence properties of ZnS nanowires and nanoribbons

Rapid synthesis of wurtzite ZnS nanowires and nanoribbons has been achieved by a simple thermal evaporation of ZnS powder onto Si substrate in the presence of Au catalyst. A vapor-liquid-solid process is proposed for the formation of the ZnS nanostructures. The flow rate of the inert carrier Ar gas along with the temperature play an important role in defining the morphology of the ZnS nanostructures. The morphological change of the ZnS nanostructures and their growth sequence were studied through scanning electron microscopy. Room-temperature photoluminescence measurements showed intense blue emission at approximately 398 nm from both the nanowires and the nanoribbons.     

Highly Ordered Self‐Assembly of Native Proteins into 1D, 2D,and 3D Structures Modulated by the Tether Length of Assembly‐Inducing Ligands

In nature, proteins self‐assemble into various structures with different dimensions. To construct these nanostructures in laboratories, normally proteins with different symmetries are selected. However, most of these approaches are engineering‐intensive and highly dependent on the accuracy of the protein design. Herein, we report that a simple native protein LecA assembles into one‐dimensional nanoribbons and nanowires, two‐dimensional nanosheets, and three‐dimensional layered structures controlled mainly by small‐molecule assembly‐inducing ligands RnG (n =1, 2, 3, 4, 5) with varying numbers of ethylene oxide repeating units. To understand the formation mechanism of the different morphologies controlled by the small‐molecule structure, molecular simulations were performed from microscopic and mesoscopic view, which presented a clear relationship between the molecular structure of the ligands and the assembled patterns. These results introduce an easy strategy to control the assembly structure and dimension, which could shed light on controlled protein assembly.     

Self‐Assembly of Wireframe DNA Nanostructures from Junction Motifs

Wireframe frameworks have been investigated for the construction of complex nanostructures from a scaffolded DNA origami approach; however, a similar framework is yet to be fully explored in a scaffold‐free “LEGO” approach. Herein, we describe a general design scheme to construct wireframe DNA nanostructures entirely from short synthetic strands. A typical edge of the resulting structures in this study is composed of two parallel duplexes with crossovers on both ends, and three, four, or five edges radiate out from a certain vertex. By using such a self‐assembly scheme, we produced planar lattices and polyhedral objects.     

Synchronization of Two Assembly Processes To Build Responsive DNA Nanostructures

Herein, we report a strategy for the synchronization of two self‐assembly processes to assemble stimulus‐responsive DNA nanostructures under isothermal conditions. We hypothesized that two independent assembly processes, when brought into proximity in space, could be synchronized and would exhibit positive synergy. To demonstrate this strategy, we assembled a ladderlike DNA nanostructure and a ringlike DNA nanostructure through two hybridization chain reactions (HCRs) and an HCR in combination with T‐junction cohesion, respectively. Such proximity‐induced synchronization adds a new element to the tool box of DNA nanotechnology. We believe that it will be a useful approach for the assembly of complex and responsive nanostructures.     

Dynamic and Quantitative Control of the DNA‐Mediated Growth of Gold Plasmonic Nanostructures

Reproducible and controllable growth of nanostructures with well‐defined physical and chemical properties is a longstanding problem in nanoscience. A key step to address this issue is to understand their underlying growth mechanism, which is often entangled in the complexity of growth environments and obscured by rapid reaction speeds. Herein, we demonstrate that the evolution of size, surface morphology, and the optical properties of gold plasmonic nanostructures could be quantitatively intercepted by dynamic and stoichiometric control of the DNA‐mediated growth. By combining synchrotron‐based small‐angle X‐ray scattering (SAXS) with transmission electron microscopy (TEM), we reliably obtained quantitative structural parameters for these fine nanostructures that correlate well with their optical properties as identified by UV/Vis absorption and dark‐field scattering spectroscopy. Through this comprehensive study, we report a growth mechanism for gold plasmonic nanostructures, and the first semiquantitative revelation of the remarkable interplay between their morphology and unique plasmonic properties.     

Chirally Twisted Ultrathin Polydopamine Nanoribbons: Synthesis and Spontaneous Assembly of Silver Nanoparticles on Them

Polydopamine (PDA) is a synthetic polymeric material with immense potential in biomedical and surface functionalization applications. Herein, we have screened self-assemblies formed by Phenylalanine-based amphiphiles (Phe-AMPs) as soft templates for preparing chiral PDA nanostructures. Our study revealed that the amphiphile 2 endowed with a primary amine residue afforded chirally-twisted ultrathin nanoribbons of PDA under optimized conditions. The chirality at the Phe residue of 2 modulated the twist-chirality of the PDA nanoribbons; the l -2 resulted in nanoribbons with right-handed twist, whereas the d -2 induced a left-handed twist to the ribbons. The racemic mixture of these two amphiphiles produced flat, achiral tapes. The PDA ribbon thickness was ≈5.86±0.40 nm, whereas its width and length were ≈133.5±3.2 nm and >5000 nm, respectively. Upon dialysis, hollow PDA nanotubes were obtained due to curling of the PDA nanoribbons. These PDA-nanoarchitectures were employed to spontaneously form and assemble Ag-nanoparticles along the edges of the PDA nanoribbons. In this work we are reporting chirality controlled synthesis of PDA nanostructures for the first time.