Self‐Assembled Fluorescent and Antibacterial GHK‐Cu Nanoparticles for Wound Healing Applications

GHK‐Cu is demonstrated with the abilities to improve wound healing, accelerate anti‐inflammatory activity, and repair DNA damage. However, the instability of the GHK‐Cu in biological fluids is always a big challenge for its long‐term and efficient function at the target site. Therefore, the self‐assembled GHK‐Cu nanoparticles (GHK‐Cu NPs) are investigated in this work to solve the instability issue. The crystalline nanostructure within the GHK‐Cu nanoparticles offers them visible and near‐infrared fluorescent properties. With the excellent self‐assembly performance, the antibacterial properties of GHK‐Cu NPs are demonstrated using E. coli and S. aureus. The L929 dermal fibroblast cells are utilized to prove the good biocompatibility and enhanced wound healing applications of GHK‐Cu NPs. This study could pave the way for the design and elaboration of a new class of fluorescent peptides with various biological functions in biomedical applications.     

Self‐Organization of Anisotropic and Binary Colloids in Thermo‐Switchable 1D Microconfinement

Anisotropic and binary colloids self‐assemble into a variety of novel supracolloidal structures within the thermo‐switchable confinement of molecular microtubes, achieving structuring at multiple length scales and dimensionalities. The multistage self‐assembly strategy involving hard colloidal particles and a soft supramolecular template is generic for colloids with different geometries and materials as well as their binary mixtures. The colloidal architectures can be controlled by colloid shape, size, and concentration. Colloidal cubes align in chains with face‐to‐face arrangement, whereas rod‐like colloids predominantly self‐organize in end‐to‐end configurations with their long axis parallel with the long axis of the microtubes. The 1D microconfinement imposed on binary mixtures of anisotropic and isotropic colloids further increases the diversity of colloid‐in‐tube structures. In cube–sphere mixtures, cubes may act as additional confiners, locking in colloidal sphere chains, while a “colloidal Morse code” is generated where rods and spheres alternate in the case of rod–sphere mixtures. The versatile confined colloidal superstructures including their thermoresponsive assembly and disassembly are relevant for the development of stimulus–responsive materials where controlled release and encapsulation are desired.     

Liquid‐Crystal‐Mediated Self‐Assembly of Porous α‐Fe2O3 Nanorods on PEDOT:PSS‐Functionalized Graphene as a Flexible Ternary Architecture for Capacitive Energy Storage

A novel aqueous‐based self‐assembly approach to a composite of iron oxide nanorods on conductive‐polymer (CP)‐functionalized, ultralarge graphene oxide (GO) liquid crystals (LCs) is demonstrated here for the fabrication of a flexible hybrid material for charge capacitive application. Uniform decoration of α‐Fe₂O₃ nanorods on a poly(3,4‐ethylene‐dioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)‐functionalized, ultralarge GO scaffold results in a 3D interconnected layer‐by‐layer (LBL) architecture. This advanced interpenetrating network of ternary components is lightweight, foldable, and possesses highly conductive pathways for facile ion transportation and charge storage, making it promising for high‐performance energy‐storage applications. Having such structural merits and good synergistic effects, the flexible architecture exhibits a high specific discharge capacitance of 875 F g^?1 and excellent volumetric specific capacitance of 868 F cm^?3 at 5 mV s^?1, as well as a promising energy density of 118 W h kg^?1 (at 0.5 A g^?1) and promising cyclability, with capacity retention of 100% after 5000 charge–discharge (CD) cycles. This synthesis method provides a simple, yet efficient approach for the solution‐processed LBL insertion of the hematite nanorods (HNR) into CP‐functionalized novel composite structure. It provides great promise for the fabrication of a variety of metal‐oxide (MO)‐nanomaterial‐based binder and current collector‐free flexible composite electrodes for high‐performance energy‐storage applications.     

Destabilization of Thiolated Gold Clusters for the Growth of Single‐Crystalline Gold Nanoparticles and Their Self‐Assembly for SERS Detection

Thiolate‐protected gold nanoclusters with high chemical stability are exploited extensively for fundamental research and utility in chosen applications. Here for the first time, the controlled destabilization of extraordinarily stable thiolated gold clusters for the growth of single‐crystalline gold nanoparticles (AuNPs) is demonstrated, which was achieved simply via the oxidation of surface‐protecting thiolates into disulfides by hydrogen peroxide under basic condition. By combining with our experimental observations over the entire destabilization and growth process, the new growth mechanism from clusters to AuNPs is revealed by density functional theory (DFT) calculations. It is found that the size of AuNPs decreases with the increase of hydrogen peroxide concentration due to the generation of more nuclei at the higher hydrogen peroxide concentrations. In addition, the preparation of AuNPs is tuned by changing the concentration of hydrogen peroxide, and they are self‐assembled into microspheres via an evaporation‐mediated process, which can induce strong plasmonic coupling between adjacent AuNPs for ultrasensitive surface‐enhanced Raman scattering detection. The present work demonstrates a facile route to functionalize and engineer AuNPs via controlling the reaction conditions and the ratio of precursors, and thus bring new possibilities for using more clusters as precursors to construct novel nano/microstructures for various applications.     

Zinc Oxide–Porphyrin Hybrid Rhombuses: Catalytically Active Microstructures via Self‐Assembly

A novel self‐assembled organic–inorganic hybrid structure consisting of zinc oxide and two oppositely charged porphyrins, showing significantly enhanced photocatalytic activity, is presented. Electrostatic self‐assembly of the cationic tetra‐(N‐methyl‐4‐pyridyl)porphyrin (TMPyP) with preformed assemblies of ZnO nanorods and the anionic tetra‐(4‐sulfonatophenyl)porphyrin (TPPS) in ethanol results in porphyrin microrhombuses decorated with ZnO nanorods. The structure formation is followed spectroscopically. The shape of the microrhombuses and the number of attached ZnO nanoparticles can be tuned through the porphyrin ratio TMPyP/TPPS. An enhanced and selective catalytic activity is found, giving insight into the degradation mechanism. Due to the tool‐box principle and its versatility, the concept may have great impact in fields such as solar‐energy conversion and optoelectronics.     

Self‐Assembly of Ag6 Clusters into Nanowires for Nonenzymatic Electrochemical Sensing of Glucose

Self‐assembly of metal nanoclusters into 3D ordered superstructures and the exploration of their electrochemical properties are highly significant for fundamental research and practical application. In this study, atomically precise Ag₆(NALC)₅ nanoclusters are successfully synthesized and their structure is determined carefully. It is interesting that the prepared Ag₆(NALC)₅ nanoclusters can be self‐assembled into ultrafine nanowires, long ribbons, and finally 3D porous network in the mixed solution of water and ethanol, which can be attributed to the solvent polarity, static electricity interaction between ligands, and the possible Van der Waals attractions. Such assembly phenomenon lays a foundation for the future fabrication of silver clusters‐based nanodevices. In addition, the synthesized silver nanoclusters can be used for electrochemical sensing of glucose with high detection sensitivity, selectivity, and low limit of detection. This work is expected to be helpful for the synthesis of atomically precise metal nanoclusters and their applications in fabrication of nanodevices for chemical sensors.     

Carbon Dots‐Cluster‐DOX Nanocomposites Fabricated by a Co‐Self‐Assembly Strategy for Tumor‐Targeted Bioimaging and Therapy

Carbon‐based nanomaterials could afford versatile potential applications in biomedical optical imaging and as nanoparticle drug carriers, owing to their promising optical and biocompatible capabilities. In this paper, it is first found that amphipathic cetylpyridinium chloride (CPC)‐stabilized oil‐soluble carbon dots (CDs) could self‐assemble into hydrophilic CDs clusters with hydrophobic core under ultrasound, in which CPC acts as carbon source, stabilizer, and phase transfer agent. Next, the size‐control (for size‐dependent passive tumor targeting) and doxorubicin (DOX) uploading of aqueous CDs clusters, and subsequent surface charge modification via overcoating with cRGD‐ and octylamine‐modified polyacrylic acid (cRGD‐PAA‐OA) (reversing their surface charges into negative and introducing active tumor‐targeting ability) are explored systematically. Based on this sequential administration mode, CDs‐cluster‐DOX/cRGD‐PAA‐OA nanocomposites exhibit selective human malignant glioma cell line (U87MG) tumor targeting. In in vitro drug release experiments, the nanocomposites could release DOX timely. Owning to the dual tumor targeting effects and seasonable drug release, CDs‐cluster‐DOX/cRGD‐PAA‐OA show remarkably tumor targetability and enhanced antitumor efficacy (and reduced adverse reaction), comparing to free DOX in animal models. These results indicate that fabricating nanocomposite via co‐self‐assembly strategy is efficient toward drug delivery system for tumor‐targeting theranostic.     

Self‐Collimation in Photonic Crystals: Applications and Opportunities

A comprehensive review considering recent advances in self‐collimation and its applications in optical integration is covered in the current article. Self‐collimation is compared to the conventional technique of photonic bandgap engineering to control the light propagation in photonic crystal‐based structures. It is fully discussed how the self‐collimation phenomenon can be tailored to be independent of the incident angle and polarization. This adds substantial flexibility to the structure to overcome light coupling challenges and simultaneously aids in the omission of bulk and challenging elements, including polarizers and lenses from optical integrated circuits. Additionally, designed structures have the potential to be rescaled to operate in any desired frequency range thanks to the scalability rule in the field of electromagnetics. Moreover, it is shown that one can boost the coupling efficiency by applying an anti‐reflection property to the structure, which provides not only efficient index matching but also the matching between external waves with uniform amplitude and Bloch waves with periodic amplitude.     

Self‐Assembly of Spherical or Rod‐Shaped Magnetic Nanocrystals onto Curved Substrates Governed by the Radius of Curvature

The way the assembly of colloidal nanostructures into heterostructures takes place substantially affects their physicochemical properties and performance. The layer‐by‐layer self‐assembly has shown in this regard a huge ability to drive nanomaterials onto curved substrates. Hindering the clustering to improve the distribution and allocation of nanoparticles on these assemblies can be partially controlled by geometric frustration, herein demonstrated driving magnetic nanocrystals with different morphology onto spherical substrates of tuned curvature.     

Self‐assembly of p‐tert‐butyl thiacalix[4]arenes and metal cations into nanoscale three‐dimensional particles

The shape of supramolecular aggregates based on stereoisomers of p‐tert‐butyl thiacalix[4]arenes functionalized with secondary, tertiary amide and hydrazide groups at the lower rim in cone, partial cone and 1,3‐alternate conformations with several metal cations were investigated by atomic force microscopy. The examined p‐tert‐butyl thiacalix[4]arenes form host–guest complexes; dimers, spherics ellipsoids and elongated nanoscale particles depending on the conformation of macrocycles, the nature of the binding centers and the nature of the metal cation. Only associates formed by p‐tert‐butyl thiacalix[4]arenes with morpholide groups at the lower rim in cone conformation with silver cations exhibited a higher antimicrobial activity. Copyright © 2012 John Wiley & Sons, Ltd.     

Controlled Self‐Assembly of Mesoporous CuO Networks Guided by Organic Interlinking

The controlled aggregation of copper oxide nanoparticles (CuO NPs) induced by a multitopic carboxylic acid allows the formation of mesoporous structures with high surface area, in the order of 100 m² g^?1, as demonstrated herein. The main novelty in the designed process is the use, as a previous step, of a sacrificeable monotopic carboxylate ligand for capping the CuO NPs. This step avoids the often observed unwanted behavior of uncontrolled aggregation and material densification. The monotopic 3,6,9‐trioxadecanoate (HTODA) is used as the capping agent to prepare TODA@CuO, a starting material that forms colloidal dispersions in ethanol. For NPs self‐assembly, the bulky tricarboxylic acid 4,4′,4′′,‐benzene‐1,3,5‐triyl‐tris(benzoic acid) (H₃BTB) is chosen as an efficient interlinker in the controlled aggregation. The obtained mesoporous network shows a considerable thermal stability, retaining ≈70% of its specific surface area after annealing at 300 °C under vacuum. Thermal treatment involves TODA capping agent elimination, but not BTB linker. The simultaneous reduction of the CuO NPs to a Cu₂O/Cu mixture is observed.     

An Improved Method for Site‐Specific End Modification of Zeolite L for the Formation of Zeolite L and Gold Nanoparticle Self‐Assembled Structures

The ability to site‐selectively modify micro‐ and nanosized particles has allowed for directed self‐assembly in two and three dimensions. Site‐selective modification of particles can be a complicated task requiring the pre‐organization of particles or enhanced particle fabrication methods. The aluminum silicate, zeolite L has been reported to undergo site‐specific modification at the zeolite channel entrances, post‐fabrication in a solution‐based method. The process by which the channel entrances are site selectively modified is explored here. The preliminary step of charging the zeolite channels with aqueous acid allows for catalysis of covalent bond formation at the channel entrances. Three new end‐specific modification reagents are described based on silanol and silyl ether functional groups. These reagents are purified by column chromatography and characterized by¹H NMR spectroscopy and high resolution mass spectrometry (HRMS); they provide for reliable end modification of zeolites L. Preferential reactivity at the channel entrances is also observed. The utility of the approach is demonstrated by modifying zeolite L with adamantane at the channel entrances. Site‐specific self‐assembly with β‐cyclodextrin coated gold nanoparticles can be triggered with a chemical stimulus. The resulting multivalent host‐guest interactions give gold clustered nanoparticles at the ends of the micrometer‐sized zeolites.     

Enhancement of the 808 nm Photothermal Effect of Gold Nanorods by Thiol‐Induced Self‐Assembly

Gold (Au) nanomaterials are promising photothermal agents for the selective treatment of tumor cells owing to the strong capability to convert near‐infrared (NIR) irradiation into heat energy. One basic issue for practical photothermal therapy is the enhancement of photothermal effect in NIR region. Here, various low‐molecular‐weight thiols are applied to induce one‐dimensional (1D) self‐assembly of Au nanorods (NRs), which leads to the redshift of absorption peak towards NIR region. As a result, the 1D assembled Au NRs exhibit improved photothermal effect at 808 nm in comparison to unassembled Au NRs.     

Drug‐Conjugation Induced Self‐Assembly of Feather Keratin‐Based Prodrug for Tumor Intracellular Reduction Triggered Drug Delivery

As a kind of natural protein, keratin is widely investigated in the biomedical field. Here, for the first time, a keratin‐based prodrug (PK‐SS‐D) is designed for tumor intracellular reduction triggered drug delivery, by conjugating doxorubicin (DOX) onto poly(ethylene glycol) modified keratin (PEGylated keratin, PK) with a bioreducible disulfide linkage. The protein‐drug conjugate prodrug, with a drug content of 20%, can self‐assemble into micelles with a mean hydrodynamic diameter of 175 nm and a narrow distribution. The in vitro controlled release profiles reveal the reduction triggered thiolated DOX (DOX‐SH) release behavior of the PK‐SS‐D micelles, with a cumulative drug release up to 52% within 10 d in the simulated tumor microenvironment in a sustained releasing mode, and a low drug leakage of 17% in the simulated normal physiological medium. The enhanced tumor growth inhibition of the proposed PK‐SS‐D prodrug micelles is revealed by the methyl tetrazolium (MTT) assays, although the released DOX‐SH prodrug possesses a lower tumor growth inhibition than DOX.     

Microfluidic Fabrication of Multi‐Drug‐Loaded Polymeric Microparticles for Topical Glaucoma Therapy

In this paper, the fabrication and characterization of multi‐drug‐loaded microparticles are demonstrated for topical glaucoma therapy. Specifically, latanoprost (“LAT”) and dexamethasone (“DEX”) are loaded in monodisperse microparticles (diameter ≈150 μm) of a biodegradable polymer–poly (lactic‐co‐glycolic) acid (PLGA)—using capillary microfluidics coupled with solvent evaporation. Both individual (LAT in PLGA and DEX in PLGA) and combined (LAT and DEX in PLGA) microparticle formulations are demonstrated. The morphology, size distribution and in vitro release kinetics are studied, and in vitro mucoadhesion of the formulated microparticles is also assessed. In addition, discussion is placed in how precise knowledge of the particle composition enabled by the microfluidic fabrication method and in vitro release rate measurements allow for facile topical formulation design and dose optimization. Such precision‐fabricated, multi‐drug loaded, sustained‐release microparticles are envisioned to serve as a promising platform for topical administration of ocular drugs. This could potentially reduce the frequency of eyedrop‐based drug administration from several times a day to merely once a day (or less), thus greatly facilitating patient compliance and adherence to a strict therapeutic drug regimen.     

Protein Self‐Assembly Driven by De Novo Coiled Coils and Constructing Ag Nanoparticle‐Protein Assembly Composite with High Catalytic Activity

Construction of protein self‐assembly has drawn more and more attention for understanding the natural wisdom and producing functional biomaterial. Current efforts focus on the novel driving force, dynamic control, and functionalization. In this study, protein assembly driven by de novo coiled coils is reported. By precisely designing coiled coil sequence, dimeric antiparallel coiled coils are successfully constructed and used as a linker to drive helical protein nanostructures. Furthermore, Ag nanoparticles (NPs) are subsequently biomineralized, endowing the protein assembly ability of p‐nitrophenol hydrogenation. It is noteworthy that the Ag NPs‐protein assembly composite presents a 4.19 times higher activity than traditional hydrothermal synthesized Ag NPs because of the higher affinity with substrates. The composite also demonstrates good water stability and recyclability. This article provides a manipulative strategy to drive protein assembling and reveals the Ag‐protein assembly composite a potential biomaterial in the future.