Hierarchical Assembly Strategy Research Articles

Layer‐Controllable “2.5D” DNA Origami Crystals Synthesized by a Hierarchical Assembly Strategy

AbstractThe finite periodic arrangement of functional nanomaterials on the two‐dimensional scale enables the integration and enhancement of individual properties, making them an important research topic in the field of tuneable nanodevices. Although layer‐controllable lattices such as graphene have been successfully synthesized, achieving similar control over colloidal nanoparticles remains a challenge. DNA origami technology has achieved remarkable breakthroughs in programmed nanoparticle assembly. Based on this technology, we proposed a hierarchical assembly strategy to construct a universal DNA origami platform with customized layer properties, which we called 2.5‐dimensional (2.5D) DNA origami crystals. Methodologically, this strategy divides the assembly procedure into two steps: 1) array synthesis, and 2) lattice synthesis, which means that the layer properties, including layer number, interlayer distance, and surface morphology, can be flexibly customized based on the independent designs in each step. In practice, these synthesized 2.5D crystals not only pioneer the expansion of the DNA origami crystal library to a wider range of dimensions, but also highlight the technological potential for templating 2.5D colloidal nanomaterial lattices.

Single‐Crystal Superstructures via Hierarchical Assemblies of Giant Rubik's Cubes as Tertiary Building Units

AbstractIntricate superstructures possess unusual structural features and promising applications. The preparation of superstructures with single‐crystalline nature are conducive to understanding the structure–property relationship, however, remains an intriguing challenge. Herein we put forward a new hierarchical assembly strategy towards rational and precise construction of intricate single‐crystal superstructures. Firstly, two unprecedented superclusters in Rubik's cube's form with a size of ≈2×2×2 nm3are constructed by aggregation of eight {Pr4Sb12} oxohalide clusters as secondary building units (SBUs). Then, the Rubik's cubes further act as isolable tertiary building units (TBUs) to assemble diversified single‐crystal superstructures. Importantly, intermediate assembly states are captured, which helps illustrate the evolution of TBU‐based superstructures and thus provides a profound understanding of the assembly process of superstructures at the atomic level.

Single-crystal superstructures via hierarchical assemblies of giant Rubik's cubes as tertiary building units.

Intricate superstructures possess unusual structural features and promising applications. The preparation of superstructures with single-crystalline nature are conducive to understanding the structure-property relationship, however, remains an intriguing challenge. Herein we put forward a new hierarchical assembly strategy towards rational and precise construction of intricate single-crystal superstructures. Firstly, two unprecedented superclusters in Rubik's cube's form with a size of ~ 2 × 2 × 2 nm3 are constructed by aggregation of eight {Pr4Sb12} oxohalide clusters as secondary building units (SBUs). Then, the Rubik's cubes further act as isolable tertiary building units (TBUs) to assemble diversified single-crystal superstructures. Importantly, intermediate assembly states are captured, which helps illustrate the evolution of TBU-based superstructures and thus provides a profound understanding of the assembly process of superstructures at the atomic level.

Hierarchical Assembly of Flexible Biopolymer Polyphosphate-Manganese into Nanosheets.

Polyphosphate (polyP) is one of the most compact inorganic polyanionic biopolymers that participates in various physiological processes. However, the development of polyP-based nanomaterials is still in its infancy. Here, biocompatible polyphosphate-manganese nanosheets are designed and synthesized by a hierarchical assembly strategy. The thickness and the lateral size of the resulting polyP-Mn nanosheets (PMNSs) are 5nm and 120-130nm, respectively. Molecular dynamics simulations suggested that the polyP-hexadecyl trimethyl ammonium bromide flat structure possesses a strong aggregating capacity and serves as the template for the 2D assembly of polyP-Mn. The PMNSs can activate the inflammatory response of macrophages resulting in the recovery of innate immunological functions to inhibit tumor proliferation. This work has initiated a new direction in constructing layered polyP-based nanomaterials and provides guidance for biocompatible and biodegradable biopolymer-based materials in the regulation of innate responses.

Bio-inspired Janus structural color films as visually flexible electronics

Multifunctional composite flexible sensors are essential components in flexible and stretchable electronics. In this paper, we present novel mussel-inspired Janus structural color films as visually flexible electronics. The Janus composite film with a three-layer structure, which is compozed of a conductive carbon nanotube (CNT) layer, a supporting polydimethylsiloxane (PDMS) layer and a structural color layer formed by two-dimensional colloidal crystals (2D-CCs), is prepared by a hierarchical assembly strategy. The manufactured multi-layer CNT films and the 2D-CCs are integrated on both sides of the supporting PDMS layer, respectively by the self-assembly process and the adhesion of polydopamine (PDA) to provide corresponding excellent conductivity, flexibility and visual optical sensing for the Janus composite film. It is demonstrated that the CNT films could not only increaze the contrast of structural color of the 2D-CC array as their light absorption characteristics in the broadband frequency field, but also impart the composite film with photothermal response characteristics. In addition, because of the outstanding electrical properties, visualized structural color and photothermal response, the resulting Janus structural color films show stable electrical sensing and visualized color-sensing under deformations arose by human motions and near-infrared (NIR) illumination, which could play essential roles in flexible and stretchable electronics.

Hierarchical assembly strategy to tailored nanostructures of doped-carbon/Co-based catalysts for high-performance trifunctional electrocatalysis

• Hierarchical assembly strategy is developed to synthesize trifunctional catalysts. • The electronic modulation of Co 9 S 8 from N,S-C decreases reaction energy barrier. • The hollow carbon nanotubes offer a beneficial mass/charge transport. • Co 9 S 8 -HCT shows superior electrocatalytic activity and durability for ORR/OER/HER. Developing an effective strategy to synthesize low-cost and efficient trifunctional electrocatalysts is critical to renewable energy storage and conversion but remains challenging. Herein, we report a hierarchical assembly strategy to controllably synthesize a series of doped carbon/Co-based nanocomposites with tunable morphologies and compositions. During the synthesis, a variation of urea/thiourea mass ratio exerts a dramatic effect on final nanostructures, ranging from hollow nanotube, nanosheet to nanospring. Meanwhile, Co species are successfully regulated from Co single atoms, Co nanoparticles (NPs) to Co 9 S 8 NPs. The controllable tunability allows the optimization of trifunctional electrocatalytic performance and the establishment of structure/composition-property relationships for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Among the as-obtained materials, the heterostructure of hollow carbon nanotubes/reduced graphene oxide doped with N/S and decorated with Co 9 S 8 NPs (Co 9 S 8 -HCT) shows superior electrocatalytic activity and long-term stability for ORR, OER, and HER in alkaline medium. Experimental and theoretical results show that the electrocatalytic promotion comes from the electronic modulation of Co 9 S 8 from N,S-codoped nanocarbon.

Conferring supramolecular guanosine gel nanofiber with ZIF-67 for high-performance oxygen reduction catalysis in rechargeable zinc–air batteries

Nanostructured gels have emerged as a unique material platform for energy-related applications and have been mainly focused on polymer gels in recent years. We developed a coordination-driven hierarchical assembly strategy for the general exploration of robustness supramolecular gel (SMG) materials as metal-organic framework (MOF) supports for further development of high efficiency oxygen reduction reaction electrocatalysts for rechargeable Zn–air batteries. As the first example of SMG/MOF composites, guanosine SMG (GSMG) fibres were modified by terpyridine ligands, cross-linked by Zn (II), and then anchored in-situwith ZIF-67 polyhedra to produce a special ZIF-67/Zn-GSMG heterostructure enriched in heteroatoms (B, N, C, Co, and Zn) and with a continuous rigid skeleton. Pyrolysis yielded cobalt-embedded porous carbon polyhedra/B,N dual-doped carbon nanofibers with superior oxygen reduction reaction activity, showing an exceptional potential for applications in rechargeable Zn–air batteries. The present work provides a new material platform for promising future design of functional multicomponent composites.

A hierarchical assembly strategy for near-infrared photothermal conversion: unconventional heterogeneous metalla[2]catenanes.

Herein, we report a hierarchical assembly strategy for constructing heterogeneous half-sandwich organometallic D–A (D = π-donor, A = π-acceptor) interlocked structures, and their application in near-infrared (NIR) photothermal conversion. Thienothiophene and diketopyrrolopyrrole groups were selected as the D and A units, leading to two homogeneous metalla[2]catenanes with D–D–D–D and A–A–A–A stacks, respectively. By the ordered secondary assembly of homogeneous metalla[2]catenanes, two unprecedented heterogeneous D–A metalla[2]catenanes comprising an unusual mixed D–A–D–D and unconventional D–A–A–A stacks were realized by the combination of multiple noncovalent interactions, as all demonstrated by a detailed X-ray crystallographic study. Benefiting from the mixed D–A stacking modes, NIR absorption of heterogeneous D–A metalla[2]catenanes is significantly enhanced in contrast to homogeneous metalla[2]catenanes. Thanks to the enhanced NIR absorption and the fluorescence quenching effect from half-sandwich organometallic fragments, heterogeneous D–A metalla[2]catenanes displayed high-performance NIR photothermal conversion properties (η = 27.3%).

A hierarchical assembly strategy to engineer dextran-enveloped polyurethane nanopolyplexes for robust ovarian cancer gene therapy

A hierarchical assembly strategy is herein investigated to generate bio-responsive, dextran-enveloped, bioreducible polyurethane nanopolyplexes for nonviral gene therapy against ovarian tumor. Initially, a group of poly(urethane amine)s were designed and characterized for in vitro gene transfection. The polyurethane containing 1,4-bis(3-aminopropyl)piperazine residue (PUBAP) could induce the best in vitro transfection efficacy against SKOV-3 or A2780 ovarian cancer cells. Next, dextran-enveloped PUBAP polyplexes (e-polyplexes) were constructed by a hierarchical assembly procedure involving gene neutralization with PUBAP and subsequent gene condensation with a cationic dextran (SSDP800). Such dextran comprised dextran (15 kDa) as the main chain and multiple disulfide-linked branched polyethylenimine (BPEI) oligomers as the side grafts. Additionally, folate-dextran-enveloped PUBAP polyplexes (FA-e-polyplexes) were fabricated by folate-modified SSDP800. These nanoscale-enveloped polyplexes elicited an improved colloidal stability against salt ions and negatively charged heparin, efficient endosomal escaping, and bioreduction-triggered intracellular gene release. In vitro transfection against SKOV-3 cells illustrated that FA-e-polyplexes exerted higher transfection efficiency in the serum than e-polyplexes and 25 kDa BPEI-polyplexes. In vivo, FA-e-polyplexes yielded higher transgene expression level than e-polyplexes in an SKOV-3 tumor-bearing nude mouse model. In the tumor gene therapy with a small hairpin RNA silencing vascular endothelial growth factor, FA-e-polyplexes afforded higher tumor growth inhibition than polyplexes of folate-PEGylated PUBAP and 25 kDa linear polyethylenimine as positive controls. Importantly, such gene therapy had minor toxic effects on the health of the mouse. This work highlights a practical hierarchical assembly method to construct innovative enveloped polyurethane nanopolyplexes enabling robust ovarian cancer gene therapy. Statement of SignificanceIt is indispensable to rationally update binary cationic polyplexes into ternary polyplexes for vigorous tumor gene therapy. In this work, we have confirmed that a hierarchical assembly strategy, by using initial gene neutralization and subsequent gene condensation, is facile and effective to promote cationic polyurethane polyplexes into ternary folate-dextran-enveloped polyurethane polyplexes with a relatively high gene-loading capacity. The enveloped polyplex system enables more efficient gene transfection than the PEGylated polyplex counterpart in ovarian cancer in vitro and in vivo, thereby affording robust ovarian cancer gene therapy. The development of innovative enveloped polyplexes may be a new direction for a non-viral gene delivery system.

Dynamic and programmable morphology and size evolution via a living hierarchical self-assembly strategy

Recent advances in the preparation of shape-shifting and size-growing nanostructures are hot topics in development of nanoscience, because many intelligent functions are always relied on their shape and dimension. Here we report a tunable manipulation of sequential self-assembled transformation in situ via a hierarchical assembly strategy based on a living thiol–disulfide exchange reaction. By tailoring the external stimuli, the reactive points can be generated at the ends of initially unimolecular micelles, which subsequently drive the pre-assemblies to periodically proceed into the hierarchically micellar connection, axial growth, bending, and cyclization processes from nanoscopic assemblies to macroscopic particles. Of particular interest would be systems that acquired the shape control and size adjustment of self-assemblies after termination or reactivation of disulfide reshuffling reaction by regulating external stimuli whenever needed. Such a hierarchical strategy for self-assembled evolution is universally applicable not only for other disulfide-linked dendritic polymers but also for exploitation of biological applications.

A hybrid-hierarchical genome assembly strategy to sequence the invasive golden mussel, Limnoperna fortunei.

BackgroundFor more than 25 years, the golden mussel, Limnoperna fortunei, has aggressively invaded South American freshwaters, having travelled more than 5000 km upstream across 5 countries. Along the way, the golden mussel has outcompeted native species and economically harmed aquaculture, hydroelectric powers, and ship transit. We have sequenced the complete genome of the golden mussel to understand the molecular basis of its invasiveness and search for ways to control it.FindingsWe assembled the 1.6-Gb genome into 20 548 scaffolds with an N50 length of 312 Kb using a hybrid and hierarchical assembly strategy from short and long DNA reads and transcriptomes. A total of 60 717 coding genes were inferred from a customized transcriptome-trained AUGUSTUS run. We also compared predicted protein sets with those of complete molluscan genomes, revealing an exacerbation of protein-binding domains in L. fortunei.ConclusionsWe built one of the best bivalve genome assemblies available using a cost-effective approach using Illumina paired-end, mate-paired, and PacBio long reads. We expect that the continuous and careful annotation of L. fortunei’s genome will contribute to the investigation of bivalve genetics, evolution, and invasiveness, as well as to the development of biotechnological tools for aquatic pest control.

Superlight, Mechanically Flexible, Thermally Superinsulating, and Antifrosting Anisotropic Nanocomposite Foam Based on Hierarchical Graphene Oxide Assembly.

Lightweight, high-performance, thermally insulating, and antifrosting porous materials are in increasing demand to improve energy efficiency in many fields, such as aerospace and wearable devices. However, traditional thermally insulating materials (porous ceramics, polymer-based sponges) could not simultaneously meet these demands. Here, we propose a hierarchical assembly strategy for producing nanocomposite foams with lightweight, mechanically flexible, superinsulating, and antifrosting properties. The nanocomposite foams consist of a highly anisotropic reduced graphene oxide/polyimide (abbreviated as rGO/PI) network and hollow graphene oxide microspheres. The hierarchical nanocomposite foams are ultralight (density of 9.2 mg·cm-3) and exhibit ultralow thermal conductivity of 9 mW·m-1·K-1, which is about a third that of traditional polymer-based insulating materials. Meanwhile, the nanocomposite foams show excellent icephobic performance. Our results show that hierarchical nanocomposite foams have promising applications in aerospace, wearable devices, refrigerators, and liquid nitrogen/oxygen transportation.

Hierarchical Assembly of Complex Block Copolymer Nanoparticles into Multicompartment Superstructures through Tunable Interparticle Associations

AbstractA challenging aim in both materials physics and chemistry is the construction of complex and functional superstructures from designed nanoscale building units. Block copolymer nanoparticles with morphological variety and compositional complexity have been made with solution‐based assembly. However, routine ability to build hierarchical superstructures by inter‐nanoparticle association is not yet possible. A hierarchical assembly strategy of organizing pre‐formed spherical block copolymer nanoparticles into superstructures, including linear, circular, and close‐packed arrays, via tunable interparticle interactions is presented. Solution‐state mixtures are made of two amphiphilic diblock copolymers, poly(acrylic acid)‐block‐poly(methyl methacrylate) (PAA‐b‐PMMA) and poly(acrylic acid)‐block‐polybutadiene (PAA‐b‐PB) with additional crown ether functionalities grafted onto 40 mol% of the AA repeat units on the PAA‐b‐PMMA diblock copolymer. Through kinetic control of the solution assembly process in aqueous/N,N‐dimethylformamide (DMF) mixtures (4:1 water:DMF), spherical nanoparticles with compositional complexity confined in both the core and shell are obtained. Benefiting from host‐guest chemistry, interparticle association is triggered and tuned by the addition of di‐functional organoamines due to amine‐crown ether complexation. The resultant multiparticle superstructures contain well‐defined multicompartments within individual, constituent nanoparticles due to the local separation of unlike PB and PMMA hydrophobic blocks within the cores of the individual particles. Through competitive complexation with potassium ions, the superstructures are disassembled into individual multicomparment nanoparticles.

Computationally Optimised DNA Assembly of synthetic genes

Gene synthesis is hampered by two obstacles: improper assembly of oligonucleotides; oligonucleotide defects incurred during chemical synthesis. To overcome the first problem, we describe the employment of a Computationally Optimised DNA Assembly (CODA) algorithm that uses the degeneracy of the genetic code to design overlapping oligonucleotides with thermodynamic properties for self-assembly into a single, linear, DNA product. To address the second problem, we describe a hierarchical assembly strategy that reduces the incorporation of defective oligonucleotides into full-length gene constructs. The CODA algorithm and these biological methods enable fast, simple and reliable assemblies of sequence-correct full-length genes.