Enzyme-Instructed Self-Assembly (EISA) and Hydrogelation of Peptides

Self-assembly is a powerful tool for constructing supramolecular materials for many applications, ranging from energy harvesting to biomedicine. Among the methods to prepare supramolecular materials for biomedical applications, enzyme-instructed self-assembly (EISA) has several advantages. Herein, the unique properties and advantages of EISA in preparing biofunctional supramolecular nanomaterials and hydrogels from peptides are highlighted. EISA can trigger molecular self-assembly in situ. Therefore, using overexpression enzymes in disease sites, supramolecular materials can be formed in situ to improve the selectivity and efficacy of the treatment. The precursor may be involved during the EISA process, and it is actually a two-component self-assembly process. The precursor can help to stabilize the assembled nanostructures of hydrophobic peptides formed by EISA. More importantly, the precursor may determine the outcome of molecular self-assembly. Recently, it was also observed that EISA can kinetically control the peptide folding and morphology and cellular uptake behavior of supramolecular nanomaterials. With the combination of other methods to trigger molecular self-assembly, researchers can form supramolecular nanomaterials in a more precise mode and sometimes under spatiotemporal control. EISA is a powerful and unique methodology to prepare supramolecular biofunctional materials that cannot be generated from other common methods.     

Reaction inside a viral protein nanocage: Mineralization on a nanoparticle seed after encapsulation via self-assembly

Protein nanocages are ideal templates for the bio-inspired fabrication of nanomaterials due to several advantageous properties.During the mineralization of nanoparticles (NPs) inside protein nanocages,most studies have employed a common strategy:seed formation inside protein nanocages followed by seeded NP growth.However,the seed formation step is restricted to gentle reaction conditions to avoid damage to the protein nanocages,which may greatly limit the spectrum of seed materials used for NP growth.We put forward a simple route to circumvent such a limitation:encapsulation of a preformed NP as the seed via self-assembly,followed by the growth of an outer metal layer.Using such a method,we succeeded in mineralizing size-tunable Au NPs and Au@Ag core-shell NPs (＜10 nm in diameter) with narrow size distributions inside the virus-based NPs of simian virus 40.The present route enables the utilization of NPs synthesized under any conditions as the starting seeds for nanomaterial growth inside protein nanocages.Therefore,it potentially leads to novel bioinorganic chimeric nanomaterials with tailorable components and structures.     

生物分子模板法制备低维金属纳米材料研究进展（Ⅱ）

本文概述了蛋白质、DNA等生物分子模板表面化学沉积制备低维金属纳米材料的最新研究进展。蛋白质可自组装形成不同层次的纳米结构,而DNA分子可自组装形成纳米线和网状结构。这些不同的纳米结构可作为模板,化学沉积,制备金属纳米管、纳米线等一维或二维纳米材料。金属纳米管和纳米线具有导电、导热、磁性和具有特殊的量子效应,在电磁活性复合材料,可控缓释系统、纳米器件和纳米电路等领域有重要的应用前景。     

Applications of bio-inspired special wettable surfaces

In this review we focus on recent developments in applications of bio-inspired special wettable surfaces. We highlight surface materials that in recent years have shown to be the most promising in their respective fields for use in future applications. The selected topics are divided into three groups, applications of superhydrophobic surfaces, surfaces of patterned wettability and integrated multifunctional surfaces and devices. We will present how the bio-inspired wettability has been integrated into traditional materials or devices to improve their performances and to extend their practical applications by developing new functionalities.     

Standing arrays of gold nanorods end-tethered with polymer ligands

Nanomaterials with vectoral electromagnetic properties have potential applications in solar cells, plasmonic cavity resonators, light polarizers, and biosensing. Here a new, simple, solution-based method for producing nanomaterials comprising vertically aligned standing arrays of gold nanorods (NRs) end-functionalized with polymer ligands is reported. The method utilizes the side-by-side assembly of the NRs into large 2D superlattices, followed by the precipitation of the lattices on a solid substrate. The critical design rules for the self-assembly of superlattices are demonstrated, and they show the generality of the method by forming standing arrays from the NRs end-tethered with poly(N-vinylcarbazole) or with polystyrene molecules.     

Self-assembly: a minimalist route to the fabrication of nanomaterials

Self-assembly of molecular or nonmolecular components by non-covalent interactions offers an invaluable tool for the preparation of discrete nanostructures and extended 2D and 3D materials, which are often not accessible by any other fabrication process. In this article we summarize the most recent advances in the generation of nanomaterials such as self-assembled monolayers (SAMs) and structures formed from amphiphilic molecules, colloids, peptides, and polymers by nontemplated self-assembly either at the solid state or in solution. The current status of templated self-assembly and the use of self-assembled structures as template and for patterning other materials is also covered. A special emphasis is placed on strategies presenting either original and somehow exploratory approaches, eventually combining bottom-up and top-down methods, or that concern methods for the production of materials with potential application, e.g., in photonics, as sensors, for drug delivery and electric and magnetic devices. In all the sections, we outline self-organization and applications enabled with self-separated block copolymers.     

Histidine as a key modulator of molecular self-assembly: Peptide-based supramolecular materials inspired by biological systems

Histidine, a versatile proteinogenic amino acid, plays a broad range of roles in all living organisms and behaves as a key mediator of the interactions of biomolecules with inorganic constituents. The self-assembly of histidine-rich peptides and proteins is critical in biology, as the histidine unit is both a multifunctional regulator and an ideal motif for the construction of complex biological structures. In particular, non-covalent interactions between the imidazole ring and other molecular building blocks and metal ions are routinely employed to generate these complexes. Therefore, this strategy can be duplicated in an artificial context to create sophisticated bioactive materials. In this review, we first highlight a clear perspective of the bio-inspired design strategies which can replicate the hierarchical structure of biological systems allowing the engineering of the supramolecular self-assembly of histidine-functionalized peptides. We further summarize advancements in the field of peptide supramolecular structures incorporating histidine residues in the peptide backbone to generate organized functional supramolecular biomaterials with customizable features. We also discuss significant advances and future prospects in supramolecular self-assembly of histidine-functionalized peptides, as well as provide an overview of advanced techniques for the fabrication of histidine-based biomaterials for bio-nanotechnology, optoelectronic engineering, and biomedicine. Overall, artificial supramolecular materials based on histidine functionalized peptides, motivated by the intriguing properties discovered in natural proteins, bear the potential to boost the creation of sustainable bio-inspired materials.     

One-dimensional 8-hydroxyquinoline metal complex nanomaterials: synthesis,optoelectronic properties,and applications

One-dimensional (1D) 8-hydroxyquinoline metal complex nanomaterials exhibit distinctive characteristics that differ from those of their bulk counterparts. Owing to their small size, shape anisotropy, unique structures, and novel properties, these organometallic 1D nanostructures are promising candidates for various devices. This review highlights current progress in the synthesis of 1D 8-hydroxyquinoline metal complex nanomaterials and summarizes their optoelectronic properties and applications. The mainly synthetic strategies are divided into three categories, which include vapor phase growth, solution phase growth, and self-assembly. Special attention is paid to the formation mechanisms and the control measures for 1D nanostructured 8-hydroxyquinoline metal complexes. Other new methods such as template-based synthesis and electrospinning are briefly described. Merits and shortcomings of each synthetic strategy are simply discussed. Then, a variety of optoelectronic properties including luminescence, field emission, charge transport, photoconductivity, and photo-switching properties are reviewed, and their applications in optoelectronic devices, field emission, and templates are also surveyed. In the end, concise conclusions are provided, and personal perspectives on future investigations of 1D 8-hydroxyquinoline metal complex nanomaterials are proposed.     

Real-time translocation of fullerene reveals cell contraction

Carbon-based nanomaterials possess unique structural, mechanical, and electronic properties that are exploited in numerous applications. The fate of nanomaterials in living systems and in the environment is largely unknown, though there is a reason for concern. Here it is shown how the interaction of fullerene with natural phenolic acid induces cell contraction. This phenomenon has a general applicability to carbon-based nanomaterials interacting with natural amphiphiles. Atomistic simulations reveal that the self-assembly of C(70)-gallic acid (GA) favors aggregation. Confocal fluorescence microscopy shows that C(70)-GA complexes translocate across the membranes of HT-29 cells and enter nuclear membranes. Confocal imaging further reveals the real-time uptake of C(70)-GA and the consequent contraction of the cell membranes. This contraction is attributed to the aggregation of nanoparticles into microsized particles promoted by cell surfaces, a new physical mechanism for deciphering nanotoxicity.     

Solution-based synthesis and design of late transition metal chalcogenide materials for oxygen reduction reaction (ORR)

Late transition metal chalcogenide (LTMC) nanomaterials have been introduced as a promising Pt-free oxygen reduction reaction (ORR) electrocatalysts because of their low cost, good ORR activity, high methanol tolerance, and facile synthesis. Herein, an overview on the design and synthesis of LTMC nanomaterials by solution-based strategies is presented along with their ORR performances. Current solution-based synthetic approaches towards LTMC nanomaterials include a hydrothermal/solvothermal approach, single-source precursor approach, hot-injection approach, template-directed soft synthesis, and Kirkendall-effect-induced soft synthesis. Although the ORR activity and stability of LTMC nanomaterials are still far from what is needed for practical fuel-cell applications, much enhanced electrocatalytic performance can be expected. Recent advances have emphasized that decorating the surface of the LTMC nanostructures with other functional nanoparticles can lead to much better ORR catalytic activity. It is believed that new synthesis approaches to LTMCs, modification techniques of LTMCs, and LTMCs with desirable morphology, size, composition, and structures are expected to be developed in the future to satisfy the requirements of commercial fuel cells.     

Shape morphing smart 3D actuator materials for micro soft robot

Stimuli-responsive materials have been used in major applications such as sensors, actuators, wearable devices, and biomedical devices owing to their ability to respond to external stimuli including heat, light, electricity, humidity, and chemicals. Strategies to trigger the stimuli-responsive, shape-morphing of two-dimensional (2D) sheets into three-dimensional (3D) shapes are of significant interest for a variety of smart applications including soft robotics. Stimuli-responsive properties can be designed by the selection of materials, structures, and processing methods. This review outlines seven broad categories of stimuli-responsive 2D soft materials for 3D smart actuator applications, namely (1) carbon nanomaterials, (2) metal nanomaterials, (3) shape memory polymers, (4) liquid crystal polymers and elastomers, (5) azobenzenes, (6) hydrogels, and (7) bio-hybrids, along with their basic mechanisms, processing methods, and applications.     

Circularly Polarized Luminescence in Nanoassemblies: Generation,Amplification, and Application

Currently, the development of circularly polarized luminescent (CPL) materials has drawn extensive attention due to the numerous potential applications in optical data storage, displays, backlights in 3D displays, and so on. While the fabrication of CPL-active materials generally requires chiral luminescent molecules, the introduction of the “self-assembly” concept offers a new perspective in obtaining the CPL-active materials. Following this approach, various self-assembled materials, including organic-, inorganic-, and hybrid systems can be endowed with CPL properties. Benefiting from the advantages of self-assembly, not only chiral molecules, but also achiral species, as well as inorganic nanoparticles have potential to be self-assembled into chiral nanoassemblies showing CPL activity. In addition, the dissymmetry factor, an important parameter of CPL materials, can be enhanced through various pathways of self-assembly. Here, the present status and progress of self-assembled nanomaterials with CPL activity are reviewed. An overview of the key factors in regulating chiral emission materials at the supramolecular level will largely boost their application in multidisciplinary fields.     

Nanobiomaterials and Nanoanalysis: Opportunities for Improving the Science to Benefit Biomedical Technologies

Nanomaterials advocated for biomedical applications must exhibit well‐controlled surface properties to achieve optimum performance in complex biological or physiological fluids. Dispersed materials with extremely high specific surface areas require as extensive characterization as their macroscale biomaterials analogues. However, current literature is replete with many examples of nanophase materials, most notably nanoparticles, with little emphasis placed on reporting rigorous surface analysis or characterization, or in formal implementation of surface property standards needed to validate structure‐property relationships for biomedical applications. Correlations of nanophase surface properties with their stability, toxicity and biodistributions are essential for in vivo applications. Surface contamination is likely, given their processing conditions and interfacial energies. Leaching adventitious adsorbates from high surface area nanomaterials is a possible toxicity mechanism. Polydimethylsiloxane (PDMS), long known as a ubiquitous contaminant in clean room conditions, chemical synthesis and microfabrication, remains a likely culprit in nanosystems fabrication, especially in synthesis, soft lithography and contact molding methods. New standards and expectations for analyzing the interfacial properties of nanoparticles and nano‐fabricated technologies are required. Surface science analytical rigor similar to that applied to biomedical devices, nanophases in microelectronics and heterogeneous catalysts should serve as a model for nanomaterials characterization in biomedical technologies.     

Toward Cluster Materials with Ordered Structures via Self-Assembly of Heterocluster Janus Molecules

Cluster materials have attracted much attention because of their unique chemical and physical properties, hitherto unseen in bulk materials. Inspired by the lipid self-assembly principle, a series of heterocluster Janus molecules (HCJMs) with atomic precision have been rationally designed and synthesized by connecting different clusters via covalent bonds for the construction of nanomaterials and nano-objects. Due to their amphiphilicity, HCJMs self-assemble into cluster-containing nanomaterials or nano-objects with versatile ordered structures beyond those observed in conventional crystals. Their hybrid composition and nanoscale size are also greatly advantageous in the study of their fine structure by electron microscopy techniques, and enable their formation mechanisms to be unraveled. Finally, the influence of the characteristics of the HCJMs on the structure and properties of the self-assembled nano-objects are explored comprehensively. This synthesis strategy will promote further development of cluster materials with advanced functions via rational molecular design toward the construction of hierarchical nanostructures via molecular self-assembly.     

Synthetic Methodologies for Carbon Nanomaterials

Carbon nanomaterials have advanced rapidly over the last two decades and are among the most promising materials that have already changed and will keep on changing human life. Development of synthetic methodologies for these materials, therefore, has been one of the most important subjects of carbon nanoscience and nanotechnology, and forms the basis for investigating the physicochemical properties and applications of carbon nanomaterials. In this Research News article, several synthetic strategies, including solvothermal reduction, solvothermal pyrolysis, hydrothermal carbonization, and soft‐chemical exfoliation are specifically discussed and highlighted, which have been developed for the synthesis of novel carbon nanomaterials over the last decade.     

Self-Assembled Peptide-Based Nanodrugs: Molecular Design,Synthesis, Functionalization,and Targeted Tumor Bioimaging and Biotherapy

Functional nanomaterials as nanodrugs based on the self-assembly of inorganics, polymers, and biomolecules have showed wide applications in biomedicine and tissue engineering. Ascribing to the unique biological, chemical, and physical properties of peptide molecules, peptide is used as an excellent precursor material for the synthesis of functional nanodrugs for highly effective cancer therapy. Herein, recent progress on the design, synthesis, functional regulation, and cancer bioimaging and biotherapy of peptide-based nanodrugs is summarized. For this aim, first molecular design and controllable synthesis of peptide nanodrugs with 0D to 3D structures are presented, and then the functional customization strategies for peptide nanodrugs are presented. Then, the applications of peptide-based nanodrugs in bioimaging, chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT) are demonstrated and discussed in detail. Furthermore, peptide-based drugs in preclinical, clinical trials, and approved are briefly described. Finally, the challenges and potential solutions are pointed out on addressing the questions of this promising research topic. This comprehensive review can guide the motif design and functional regulation of peptide nanomaterials for facile synthesis of nanodrugs, and further promote their practical applications for diagnostics and therapy of diseases.     

Self-assembly nanostructures of one-dimensional antimony oxide and oxychloride

This paper reports a facile solution route (water bath heating or hydrothermal heating) for synthesizing a few Sb-based self-assembly structures including bundles of nanowires, nanowire-flowers, long nanowires, bundles of flakes, nanobelts, hollow prisms. These obtained nanomaterials were characterized by XRD, FE-SEM, TEM, SAED, and HRTEM. It was found that the morphology, size and phase of self-assembly nanostructures were strongly dependent on reaction temperature, reaction time, pH value, and heating source. In particular, nanowire-flowers and hollow prisms of antimony oxide or oxychloride have not been reported previously. A possible mechanism based on stepwise nucleation and aggregation of nanowires or flakes was also proposed.     

Directed Assembly of Hybrid Nanomaterials and Nanocomposites

Hybrid nanomaterials are molecular or colloidal‐level combinations of organic and inorganic materials, or otherwise strongly dissimilar materials. They are often, though not exclusively, anisotropic in shape. A canonical example is an inorganic nanorod or nanosheet sheathed in, or decorated by, a polymeric or other organic material, where both the inorganic and organic components are important for the properties of the system. Hybrid nanomaterials and nanocomposites have generated strong interest for a broad range of applications due to their functional properties. Generating macroscopic assemblies of hybrid nanomaterials and nanomaterials in nanocomposites with controlled orientation and placement by directed assembly is important for realizing such applications. Here, a survey of critical issues and themes in directed assembly of hybrid nanomaterials and nanocomposites is provided, highlighting recent efforts in this field with particular emphasis on scalable methods.     

One-dimensional organic and organometallic nanostructured materials

One-dimensional (1D) organic and organometallic nanomaterials are of considerable interests for both fundamental research and potential applications. They are likely to play critical roles in improving the efficiency of various electronic, photonic, biosensing devices, etc. In this context, the authors present a comprehensive review of current research on 1D organic and organometallic nanostructures. The synthetic strategies for achieving the 1D growth are elucidated by four categories: (1) template-based synthesis, (2) vapor-solid method, (3) solution-based self-assembly, and (4) dictation by the anisotropic nature. The unique thermal, optical, electronic, field emission properties and biocidal activity of 1D organic and organometallic nanostructures are consequently highlighted. Some promising applications in (integrated) molecular electronic, optoelectronic and photonic devices are also discussed.     

Chiral Polymer Dots Show Unexpected Versatility of Highly Ordered Self-Assembly into Chiroptical Liquid Crystals,Ultra-Thin Films,and Long-Ribbons

Compared to the organic counterparts, chiral self-assembly of nanomaterials shows persistency to kinetic factors such as solvent environments, and consequently, dynamic modulation of self-assembly and functions remains major challenge. Here, it is shown that alkylated, chiral polymer dots (c-PDs) give highly ordered self-assemblies with amplified chirality adaptive to solvent environments, and one-to-many hierarchical aggregation can be realized. The c-PDs tended to self-assemble into nanohelices with cubic packing in the solid state, which, thanks to the thermo-responsiveness, transformed into thermic liquid crystals upon heating. Cotton effects and circularly polarized luminescence evidenced the chirality transfer from central chirality to supramolecular chirality. At the air-water interface, the c-PDs are self-assembled into monolayers, which further stack into multiple layers with chirality transfer and highly ordered packing. In addition, undergoing a good/poor solvent exchange, the c-PDs afforded ultra-long microribbons up to a length scale of millimeters, which are constituted by the bilayer lamellar stacking. The versatile chiral self-assembly modalities with long-range ordered packing arrays of carbonized c-PDs via solvent strategy are realized. This feature is comparable to the organic species, although the c-PDs have no atomic precise structures. This work would surely expand the applications of quantum dot ordered self-assembly with adaptiveness to kinetic factors.