Dimensional Assemblies Research Articles

Lattice dynamics and elastic waves scattering by surrogate atoms in quasi-one dimensional atomic assemblies

An analytical and numerical formalism is developed to study the influence of the various positions of substitution atoms B on the scattering and transmission vibration modes in quasi-1D monatomic structures A. The matching technique is employed to calculate the dynamical properties and transmittance spectra of two substituted atomic sites. The theoretical formalism gives a complete description of the lattice dynamics and the vibration-waves propagation in the presence of the impurity sites. Numerical calculations are performed for three different positions of the two substituted atoms B in the low-dimensional structure consisting of double monatomic parallel chains. First, we examine the position where the two B atoms are adjacent in the y-direction, afterwards, we place the two sites side by side in the x-direction. Lastly, the two sites are placed in oblique configuration. The obtained results show that phonons associated to the inhomogeneous structures are strongly dependent on the scattering frequency, elastic force parameters and the position of the atomic substituted sites. In the three considered positions, the presence of the B atoms gives rise to localized vibration effects. The fluctuations observed in the vibration spectra are related to resonances due to the coherent coupling between travelling phonons and the localized vibration modes in the neighborhood of the impurity sites.

Integrated liquid metal based two-dimensional Ni–C–Al2O3 nanoarrays on enhancing electromagnetic wave absorption performance

Two-dimensional (2D) materials have motivated widespread research interest due to their combination of atomic-scale, unique electromagnetic wave interactions and electronic properties. Advancements in several technologies, including portable and wireless electronics, are at the forefront of the developments. Developing low-dimensional materials is paramount for managing environmental electromagnetic pollution and enhancing the quality of communication within the shared limited bandwidths. However, step-by-step production and testing of low dimensional assemblies tailored for microwave absorption have rarely been reported, owing to their challenging synthesis. This work demonstrates how various losses can be effectively tuned using a complex 2D-MOFs nanoarray heterojunction structure. Firstly, low melting point liquid metals are used as reaction solvents, and their atomically thin interfaces are used to synthesize 2D Al(OH)3. The obtained 2D Al(OH)3 have been subsequently used as hydrothermal templates to construct unique Ni MOF derivative nanoarrays. Finally, nanocomposites are fabricated from the obtained low-dimensional materials. The unique morphology and nano-arrangement feature exceptional microwave absorption properties. The electromagnetic interactions have been fully characterized and an effective absorption bandwidth of 6.13 GHz can be achieved at 2.1 mm thickness of the fabricated nanocomposite. This work provides an avenue for exploring low dimensional morphologies and compositions for the production of high-quality electromagnetic wave nano-composites.

Rational Fabrication of Multiple Dimensional Assemblies from Tryptophan-Based Racemate.

Fabricating structural complex assemblies from simple amino acid-based derivatives is attracting great research interests due to their easy accessibility and preparation. However, the morphological regulation of racemates (an equimolar mixture of enantiomers) were largely overlooked. In this work, through rational modulation of kinetic and thermodynamic parameters, we achieved multiple dimensional architectures employing tryptophan-based racemate (RPWM). Upon assembling, 1D bundled nanofibers, 2D lamellar nanostructure and 3D urchin-like microflowers could be obtained depending on the solvents used. The corresponding morphology evolutions were successfully illustrated by changing the enantiomeric excess (ee) value. Moreover, for RPWM, uniform 0D nanospheres were formed in H2 O under 4 °C, which could spontaneously convert into lamella under ambient temperature. Taking advantages of its temperature-responsive phase change behavior, RPWM assemblies exhibited excellent removal efficiency for organic dye RhB, and could be reused for several consecutive cycles without significant changes in its removal performance. Taken together, it's rational to envision that the engineering of racemates assembly pathways can greatly increase the robustness in a wide variety of supramolecular materials and further lead to their blooming versatile applications.

Minimizing Cost of Assembly of an Interrelated Dimensional Chain Product Using ABC Algorithm

Selective assembly is a method where components made with wider tolerance are grouped into a number of bins. Based on the best combination of the bin, the corresponding group components are randomly selected and matched together to make an assembly. Existing techniques focused on equal group number partitioning of components, equal probability, equal group width, and equal area methods to minimize either clearance variation or surplus parts using different optimization techniques. Mostly, simple assemblies with two or three components are worked by various authors in the literature without considering their original dimension by considering only their component’s tolerance. In the present work, components are classified into different unequal group numbers based on their tolerance values. The interrelated dimensional assemblies are made in a single stage by matching the parts based on the best bin combination obtained by the artificial bee colony algorithm. A simple linear assembly and a three-armed knuckle joint assembly are considered examples of problems to demonstrate the effectiveness of the proposed method by minimizing the manufacturing cost.

Low-Noise Solid-State Nanopore Enhancing Direct Label-Free Analysis for Small Dimensional Assemblies Induced by Specific Molecular Binding.

Solid-state nanopores show special potential as a new single-molecular characterization for nucleic acid assemblies and molecular machines. However, direct recognition of small dimensional species is still quite difficult due the lower resolution compared with biological pores. We recently reported a very efficient noise-reduction and resolution-enhancement mechanism via introducing high-dielectric additives (e.g., formamide) into conical glass nanopore (CGN) test buffer. Based on this advance, here, for the first time, we apply a bare CGN to directly recognize small dimensional assemblies induced by small molecules. Cocaine and its split aptamer (Capt assembly) are chosen as the model set. By introducing 20% formamide into CGN test buffer, high cocaine-specific distinguishing of the 113 nt Capt assembly has been realized without any covalent label or additional signaling strategies. The signal-to-background discrimination is much enhanced compared with control characterizations such as gel electrophoresis and fluorescence resonance energy transfer (FRET). As a further innovation, we verify that low-noise CGN can also enhance the resolution of small conformational/size changes happening on the side chain of large dimensional substrates. Long duplex concatamers generated from the hybridization chain reaction (HCR) are selected as the model substrates. In the presence of cocaine, low-noise CGN has sensitively captured the current changes when the 26 nt aptamer segment is assembled on the side chain of HCR duplexes. This paper proves that the introduction of the low-noise mechanism has significantly improved the resolution of the solid-state nanopore at smaller and finer scales and thus may direct extensive and deeper research in the field of CGN-based analysis at both single-molecular and statistical levels, such as molecular recognition, assembly characterization, structure identification, information storage, and target index.

Structural analysis of mono-substituted N-butyl-pyridinium salts: in search of ionic liquids

Four mono-substituted N-butylpyridinium salts, 1-butyl-4-dimethylaminopyridinium chloride [b4dmapy]Cl, 1-butyl-4-methylpyridinium bromide [b4mpy]Br, 1-butyl-4-methylpyridinium hexafluorophosphate [b4mpy][PF6], and 1-butyl-3-methylpyridinium hexafluorophosphate [b3mpy][PF6] were synthesized and characterized using single crystal X-ray diffraction. The crystal structures were examined with the intent of identifying ion interactions leading to higher melting points of the halide salts with respect to the [PF6]– salts. The changes in hydrogen bonding, C–H⋅⋅⋅π, and van der Waals interactions have been analyzed with respect to anion, functional groups, and the symmetry of the cation to establish interdependence with the compound’s physicochemical properties. It has been observed that the cation–anion interactions are represented by highly directional hydrogen bonds and show strong preference to positions of interaction depending on the anion. The cations of the halide salts show strong tendency towards higher dimensional formations, while those of the [PF6]– salts prefer low dimensional assemblies both being based mainly on the weaker van der Waals interactions. These interactions depend on the shape of the cation but may offer certain structure-ordering rigidity accommodating variable anions.

Ultrathin Two Dimensional (2D) Supramolecular Assembly and Anisotropic Conductivity of an Amphiphilic Naphthalene-Diimide.

Two-dimensional (2D)-supramolecular assemblies of π-conjugated chromophores are relatively less common compared to a large number of recent examples on their low dimensional (0D or 1D) assemblies or 3D architectures. This article reports a rational design for the 2D supramolecular assembly of an amphiphilic core-substituted naphthalene-diimide derivative (cNDI-1). The building block contains a naphthalene-diimide (NDI) chromophore, symmetrically substituted with two dodecyl chains from the aromatic core while the imide positions are functionalized with two hydrophilic wedges containing oligo-oxyethylene chains. In water, it exhibits entropically favorable self-assembly with a critical aggregation concentration of 1.5 × 10-5 M and a lower critical solution temperature of 55 °C. The UV/vis absorption spectrum in water shows bathochromically shifted absorption bands compared to that of the monomeric dye in THF, indicating offset π-stacking among the NDI chromophores. C-H symmetric and asymmetric stretching frequencies in the FT-IR spectrum support the presence of organized hydrocarbon chains in trans conformation in the self-assembled state, similar to that in the crystalline n-alkanes, which is further supported by studying the general polarization (GP) values of a noncovalently entrapped Laurdan dye. The atomic force microscopy (AFM) image shows the formation of ultrathin (height < 2.0 nm) ribbons for the spontaneously assembled sample which eventually produces a large-area 2D nanosheet by the lateral organization. The powder X-ray diffraction pattern of the drop-casted film, prepared from the preformed aggregates, reveals sharp peaks that indicate a crystalline lamellar packing along the direction of the 2D growth. Differential scanning calorimetry trace shows the melting of the crystalline alkyl chain domain at T > 75 °C, which destroys the 2D assembly. Local-scale photoconductivity of the ordered 2D assembly, studied by the flash-photolysis time-resolved microwave conductivity (FP-TRMC) technique, reveals an anisotropic conductivity with ∼3 times larger conductivity along the parallel direction compared to that along the perpendicular one.

Recent development of pillar[n]arene-based amphiphiles

Pillar[n]arene-based amphiphiles, mainly including amphiphilic pillar[n]arenes and supra-amphiphilic pillar[n]arenes, have obtained considerable interests in recent years due to their fascinating chemical structures, various self-assembly behaviors, and widely applications. Thanks to the pillar-like frameworks and the rich host-guest recognitions of the cavities, these amphiphiles can be easily controlled to form dimensional and morphologic assemblies for multiple applications. Compared with traditional linear covalent amphiphiles, the introduction of host-guest recognitions facilitated the preparation and controllability of these supramolecular amphiphilic systems. Moreover, the host-guest recognitions endow the assemblies from pillar[n]arene-based amphiphiles with stimuli-responsive functions. In this mini-review, we summarized the chemical structures, self-assembly features, and the applications of pillar[n]arene-based amphiphiles. However, several research topics of pillar[n]arene-based amphiphiles can be further developed in the future, such as larger cavity amphiphilic pillar[n]arenes, co-assembly with 2D materials and utilization of the host-guest interactions.

Longitudinal surface plasmon resonance of gold nanoparticles as an indicator for interparticle fusions controlled by tetronics

Seed – growth (S – G) method was used to synthesize gold (Au) nanoparticles (NPs) in the presence of water soluble star polymers “tetronics” to investigate a unique photophysical behavior of Au NPs. They produced absorbance in the visible region due to longitudinal surface plasmon resonance (LSP) specifically meant for the one dimensional Au NPs such as rods, wires, and ribbons. The S – G method did not produce such morphologies rather interparticle fusions driven by the micellar assemblies of tetronic allowed Au NPs to arrange in one dimensional morphologies to generate strong LSP in the visible region. This phenomenon was mainly dependent on the pH of the medium and was only facilitated at low pH. The results showed that it was originated from the self-aggregated templating behavior of tetronic micelles under acidic reaction conditions which brought NPs together and triggered the interparticle fusions to generate one dimensional assemblies suitable for the production of LSR. The method can be applied as a sensor where photophysical response of Au NPs is pH dependent.

Nanoarchitectonics for Nanocarbon Assembly and Composite

An emerging concept, nanoarchitectonics, raises the stage of nanotechnology to materials productions with nanoscale precisions through inclusion of the other research fields. In this review article, we exemplify nanocarbon assembly and composite as successful products of the nanoarchitectonics concept. Nanocarbon materials are representative objects to demonstrate the wide possibilities of functional varieties through structural fabrication using uni-elemental zero-dimensional objects such as fullerenes, one-dimensional carbon nanotube, two-dimensional graphene, and three dimensional assemblies and composites. Here, several related examples are introduced according to classification with (i) self-assembly mainly with liquid–liquid interfacial precipitation, (ii) process-based assembly mainly with layer-by-layer assembly, and (iii) composite formation mainly with metal oxides. The research efforts in self-assembly and process-assembly somehow still stay at challenging and basic stages. In contrast, research examples on composites of nanocarbon materials with various metal oxides are aiming to practical applications especially in energy-related applications, but the latter composite approaches do not have features of precise structure controls, yet. Therefore, more aggressive introduction of the nanoarchitectonics concept to these practical composite approaches is necessary for further possibilities to create materials with much more advanced performances.

Two-dimensional peptide based functional nanomaterials

Abstract Polypeptides and proteins have a high density of chemical functionality, which can be used to construct defined macromolecular nano architectures, such as low dimensional assemblies (i.e., nanoparticles, nanofibers and nanotubes), two-dimensional nanosheets, and extended three-dimensional structures (i.e., crystalline solids). Two-dimensional nanosheets are a fundamentally important geometry that bridges the gap between low dimensional assemblies and three-dimensional structures. In view of the considerable impact on a great many fundamental and applied aspects of biological and material sciences, it is therefore significant and valuable to review the recent works related to this field. In recent years, a central goal is to design novel materials with molecular-level information that can be utilized to direct highly specific intra- and intermolecular interactions promoting self-assembly of thermodynamically stable and structurally defined two-dimensional (2D) assemblies. In this review, we present a variety of strategies for constructing the 2D nanoscale assemblies and nanomaterials using specific interactions of polypeptides or similar peptoid molecules in a well-predictable manner. These controllable 2D nanomaterials can also display a variety of functionalities. Initially, the primary and secondary structure of peptides will be introduced. Examples of controlled fabrication of two-dimensional assemblies on the nanoscale are subsequently presented based on different secondary structures of the peptides, e.g. two-dimensional crystals from α-helix, nanoscale sheets from self-assembly of collagen-mimetic peptides with triple helix, co-assembled nanosheet structures assembled from peptide-organic molecules with β-strand conformation, and 2D crystals assembled from peptoid with Σ-strand structure. Furthermore, macrofilms assembled from protein fibril arrays are introduced. These bottom-up strategies can arrange polypeptides and proteins into well-ordered 2D structures, which can have wide-ranging applications, such as membrane-based separations with specific mechanical properties, the control of surface properties in nanodevice and nanosensor fabrication, retroviral transduction in biology and diagnosis of some disease in biomedicine.

Three dimensional titanium molybdenum nitride nanowire assemblies as highly efficient and durable platinum support for methanol oxidation reaction

To achieve the practical application of direct methanol fuel cells, the development of highly efficient and durable electrocatalyst for methanol oxidation reaction is urgently needed. Herein, an effective approach is developed to fabricate three dimensional porous titanium nitride with an urchin-like structure, which are composed of numerous interactive nanowire assemblies. When being used as the platinum support, the resulting electrocatalyst delivers a mass activity and specific activity that are both around 4.3 times greater with respect to Pt/C catalyst. Moreover, the activity stability and structural durability of the novel catalyst are also confirmed by comprehensive experimental analysis. This study provides a new way for improving the performance of methanol oxidation reaction by combining the advantages of three dimensional structure, inherent electrochemical durability and strong metal support interaction.

Moiré-pattern interlayer potentials in van der Waals materials in the random-phase approximation

Stacking-dependent interlayer interactions are important for understanding the structural and electronic properties in incommensurable two dimensional material assemblies where long-range moir\'e patterns arise due to small lattice constant mismatch or twist angles. Here, we study the stacking-dependent interlayer coupling energies between graphene (G) and hexagonal boron nitride (BN) homo- and hetero-structures using high-level random-phase approximation (RPA) ab initio calculations. Our results show that although total binding energies within LDA and RPA differ substantially between a factor of 200%-400%, the energy differences as a function of stacking configuration yield nearly constant values with variations smaller than 20% meaning that LDA estimates are quite reliable. We produce phenomenological fits to these energy differences, which allows us to calculate various properties of interest including interlayer spacing, sliding energetics, pressure gradients and elastic coefficients to high accuracy. The importance of long-range interactions (captured by RPA but not LDA) on various properties is also discussed. Parameterisations for all fits are provided.

Self-sorting in mixed fluorinated/hydrogenated assemblies

Mixtures of fluorinated and hydrogenated compounds display peculiar properties arising from their mutual phobicity and the same applies to semifluorinated species in which a reciprocal phobicity pattern exists within the same molecule. The interest in assemblies comprising these species stems from the ease in which self-sorting can take place, allowing the preparation of compartmentalised molecular aggregates with unique hydrophobic patterns or surface features. Most importantly, this is the result of molecular properties rather than specifically designed fabrication techniques. This brief overview describes some examples that are instrumental to present the features of fluorinated/hydrogenated supramolecular assemblies in which self-sorting of the dislike units takes place at different length scales. This review is focussed on flat assemblies such as self-assembled monolayers on gold surfaces, Langmuir Blodgett films and on three dimensional assemblies such as micelles, vesicles and nanoparticles.

Two dimensional palladium nanoparticle assemblies as electrochemical dopamine sensors

Two dimensional assemblies of palladium nanoparticles (PdNPs) were generated by in situ reduction of [PdCl4]2− ions attached to polyethyleneimine silane functionalized silicon and indium tin oxide (ITO) coated glass surfaces. An average size of 7.8±3.0nm was determined from atomic force microscopy (AFM) imaging. Surface zeta potential measurements enabled us to track the variation in surface charge during different steps of PdNP generation. Differential pulse voltammetry (DPV) in combination with impedance spectroscopy (IS) was used for the detection of dopamine (DA). A linear range of 2.5–130µM was observed for DA alone and in the presence of uric acid and ascorbic acid. In addition, impedance measurements showed an increase in conductance with increasing DA concentration in solution, which led to a calibration curve with a linear range of 0.05–130µM with the detection limit as low as 25nM (S/N=3).

Microfluidic-enhanced 3D bioprinting of aligned myoblast-laden hydrogels leads to functionally organized myofibers invitro and invivo.

We present a new strategy for the fabrication of artificial skeletal muscle tissue with functional morphologies based on an innovative 3D bioprinting approach. The methodology is based on a microfluidic printing head coupled to a co-axial needle extruder for high-resolution 3D bioprinting of hydrogel fibers laden with muscle precursor cells (C2C12). To promote myogenic differentiation, we formulated a tailored bioink with a photocurable semi-synthetic biopolymer (PEG-Fibrinogen) encapsulating cells into 3D constructs composed of aligned hydrogel fibers. After 3-5 days of culture, the encapsulated myoblasts started migrating and fusing, forming multinucleated myotubes within the 3D bioprinted fibers. The obtained myotubes showed high degree of alignment along the direction of hydrogel fiber deposition, further revealing maturation, sarcomerogenesis, and functionality. Following subcutaneous implantation in the back of immunocompromised mice, bioprinted constructs generated organized artificial muscle tissue invivo. Finally, we demonstrate that our microfluidic printing head allows to design three dimensional multi-cellular assemblies with an exquisite compartmentalization of the encapsulated cells. Our results demonstrate an enhanced myogenic differentiation with the formation of parallel aligned long-range myotubes. The approach that we report here represents a robust and valid candidate for the fabrication of macroscopic artificial muscle to scale up skeletal muscle tissue engineering for human clinical application.

Variations on the Honeycomb Topology: From Triangular- and Square-Grooved Networks to Tubular Assemblies in Uranyl Tricarballylate Complexes

Depending on the counterion, uranyl tricarballylate, UO2(tca)−, is shown to crystallize either as two-dimensional nets or as one-dimensional tubules, all with honeycomb topology and united into higher dimensional assemblies when additional metal cations (AgI, PbII) are present. A regular geometric progression involving ligand reorientation is apparent in the series, with triangular furrows in [H2NMe2][UO2(tca)]·H2O (1) followed by deepening square grooves in [UO2Ag(tca)(H2O)]·0.5H2O (2) and full closure of square tubules in [NH4][(UO2)2Pb(tca)2(NO3)(bipy)].

Ferrocene-graphene sheets for high-efficiency quenching of electrochemiluminescence from Au nanoparticles functionalized cadmium sulfide flower-like three dimensional assemblies and sensitive detection of prostate specific antigen

A signal-switchable electrochemiluminescence (ECL) aptasensor was presented for sensitive prostate specific antigen (PSA) assay using ferrocene-graphene sheets (Fc-GNs) for high-efficiency quenching of ECL from Au nanoparticles functionalized cadmium sulfide flower-like three dimensional (3D) assemblies (Au-CdS flower-like 3D assemblies). Au-CdS flower-like 3D assemblies were synthesized and employed as luminophore, exhibiting strong and stable ECL intensity, and followed by assembling captured DNA (cDNA) and hybridizing it with half of base sequence of PSA aptamer on the Au-CdS flower-like 3D assemblies modified electrode. The remaining part of the non-complementary base of the aptamer could preferentially adsorb GN with the signal switched “off” state. While in the presence of the PSA, the binding of PSA with aptamer caused desorption of aptamer from the surface of Fc-GNs and was then released from electrode surface, thus allowing the ECL signal enhancement. With the transformation of luminescence signal from “off” to “on”, the aptasensor displays high sensitivity for PSA detection with a linear range from 1pgmL−1 to 25ngmL−1 and a detection limit of 0.38pgmL−1S/N=3). Moreover, this developed method could be successfully applied to the determination of PSA in human serum samples with recoveries of 85.8–104.0%, suggesting great potential applications in biochemical analysis.

Construction of protein assemblies by host-guest interactions with cucurbiturils.

Protein assemblies are extremely interesting in chemistry and supramolecular chemistry. How to design protein assemblies with dimensional structures is important for applications. To address this challenge, cucurbituril (CB[n]s)-based strategies have been explored owing to their high affinity toward small peptide motifs, organic cations and amines. By incorporation of a small molecule guest and a peptide motif guest into N-terminals of oligomeric proteins, CB[n]s could recognize and bind to the N-terminal guests, leading to dimensional protein assemblies. The dimensional protein assemblies possess structural, stimuli-responsive and bioactive properties with great potential for in vivo applications. Herein, we reviewed the progress in the design of dimensional protein assemblies based on supramolecular interactions of CB[n]s and present the perspectives in the design of high-ordered biomaterials for biomedical applications.

Multiscale directed self-assembly of composite microgels in complex electric fields.

This study explored the application of localized electric fields for reversible directed self-assembly of colloidal particles in 3 dimensions. Electric field microgradients, arising from the use of micro-patterned electrodes, were utilized to direct the localization and self-assembly of polarizable (charged) particles resulting from a combination of dielectrophoretic and multipolar forces. Deionized dispersions of spherical and ellipsoidal core-shell microgels were employed for investigating their assembly under an external alternating electric field. We demonstrated that the frequency of the field allowed for an exquisite control over the localization of the particles and their self-assembled structures near the electrodes. We extended this approach to concentrated binary dispersions consisting of polarizable and less polarizable composite microgels. Furthermore, we utilized the thermosensitivity of the microgels to adjust the effective volume fraction and the dynamics of the system, which provided the possibility to dynamically "solidify" the assembly of the field-responsive particles by a temperature quench from their initial fluid state into an arrested crystalline state. Reversible solidification enables us to re-write/reconstruct various 3 dimensional assemblies by varying the applied field frequency.