3D Self-assembly Research Articles

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization, and Magnetic Properties

Two novel low-dimensional molecular magnetic materials were prepared by the self-assembly of 3d- and 5d-metal complexes. These are the first neutral heterobimetallic cyanobridged compounds involving one anisotropic Mn(III) Schiff base complex and one octacyanotungstate(V) per molecular unit. A slow diffusion of the constituents’ solutions leads to the formation of the 0D crystalline complex 1, due to coordination of a water molecule to the Mn center, which prevents polymer formation. A rapid mixing of reagents results in the precipitation of the microcrystalline powder of complex 2, which based on the totality of experimental data, possesses a 1D polymeric structure. The magnetic studies have shown that antiferromagnetic exchange interactions prevail in 1 (J/kB = −13.1(7) K, D = −3.0(1.3) K, zJ' = −0.16(20) K and gav = 2.00(1)); while the presence of the significant intramolecular Mn(III)–W(V) ferromagnetic coupling through cyanide bridge is characteristic for 2 (J/kB = 46.1(5) K, gMn = 2.11(3), fixed gW = 2.0). Due to the weak interchain interactions, zJ′/kB = −0.8(2) K, and compound 2 is a metamagnet with the Néel temperature of 9.5 K undergoing a spin-flip transition at 2 kOe. The slow magnetization dynamics of 2 were investigated at a DC field of 0 and 2 kOe, giving the values of τ0 32(15) and 36(15) ps, respectively, well within the range typical for single-chain magnets (SCMs). The respective ∆τ/kB values were 48.4(1.2) and 44.9(1.0) K.

3D self-assembly of microgel dispersion coordinated by an electric field

3D self-assembly of microgel dispersion coordinated by an electric field

3D self-assembly of ultrafine molybdenum carbide confined in N-doped carbon nanosheets for efficient hydrogen production.

Electrochemical water splitting has been intensively pursued as a promising approach to produce clean and sustainable hydrogen fuel. However, the lack of low-cost and high-performance electrocatalysts for the hydrogen evolution reaction (HER) hinders the large-scale application. Herein, we have rationally designed and synthesized 3D self-assembly architectures assembled from ultrafine MoC nanoparticles (0D) uniformly embedded within N-doped carbon nanosheets (2D) for the HER via a simple protocol. The well-organized 3D nanostructures are composed of very small MoC nanocrystallites (<2 nm) and free-stretching conductive carbon nanosheets with high specific surface areas and abundant mesopores, which can expose more active sites and facilitate electron/ion transport pathways. Based on the merits of the composition and configuration, the resultant hierarchical 3D self-assembly architectures exhibit remarkable electrocatalytic performance and stability for the HER.

Reversible 3D self-assembly of graphene oxide and stimuli-responsive polymers for high-performance graphene-based supercapacitors

The assembly of graphene into functional macrostructures has attracted intense interest in recent years.

3D self-assembly of aluminium nanoparticles for plasmon-enhanced solar desalination

Self-assembling aluminium nanoparticles are used to make a plasmon-enhanced device for desalination. Plasmonics has generated tremendous excitement because of its unique capability to focus light into subwavelength volumes1, beneficial for various applications such as light harvesting2,3, photodetection4, sensing5, catalysis6 and so on. Here we demonstrate a plasmon-enhanced solar desalination device, fabricated by the self–assembly of aluminium nanoparticles into a three-dimensional porous membrane. The formed porous plasmonic absorber can float naturally on water surface, efficiently absorb a broad solar spectrum (>96%) and focus the absorbed energy at the surface of the water to enable efficient (∼90%) and effective desalination (a decrease of four orders of magnitude). The durability of the devices has also been examined, indicating a stable performance over 25 cycles under various illumination conditions. The combination of the significant desalination effect, the abundance and low cost of the materials, and the scalable production processes suggest that this type of plasmon-enhanced solar desalination device could provide a portable desalination solution.

Can Nucleobase Pairs Offer a Possibility of a Direct 3D Self-assembly?

BackgroundThe nucleobase pairs are characterized by their conformational diversity in the wild. Yet a modern nanobiotechnology utilizes their planar conformations only, developing what can be called a “planar approach”. It is well established that the most energetically favorable conformations of the complementary nucleobase pairs are planar and correspond to the classical Watson-Crick nucleobase pairs.Presentation of the HypothesisThe point of interest lies in a study of a conformational capacity of the nucleobase pairs to expand the diversity of a spatial configuration and to produce the complex 3D objects from the non-planar conformations. If such a goal could be achieved, then that could definitely open the perspectives for a novel “stereo approach”.Testing the HypothesisFor the first time, basing on the first principles, we reveal an ability of the heteroassociates of the m1Cyt · m1Thy to form up to ten observable molecular complexes under standard conditions. The first three of them have population of ~90 % at standard conditions and are highly non-planar. The most energetically favorable structure has a T-shape, while the next two have an L-shape. At the same time, we show the lack of any experimental data covering a self-assembly of the m1Cyt · m1Thy base pairs.Implications of the HypothesisWe present a theoretical evidence of the fact that the conformational capacity of the nucleobase pairs is much richer from the perspective of their self-assembly than it is considered in the modern nanobiotechnology. The capability of a modified cytosine and a modified thymine to create significantly non-planar structures opens a way for the innovative “stereo approach” to construction of the nanobiotechnological devices. We believe that a modern nanobiotechnological basis can and should be extended with the new nucleic base pairs with innate ability for non-planar structures. We would like to especially emphasize a prognostic role of our algorithm in obtaining the new results.

Solving the 0-1 planning problem based on 3D DNA self-assembly technology

Solving the 0-1 planning problem based on 3D DNA self-assembly technology

Designing Biological Simulation Models Using Formalism-Based Functional and Spatial Decompositions

One of the most daunting challenges confronting computational biologists is a problem that simulation developers in all disciplines face: the design of simulation code that can be easily understood and modified despite the complexity of the systems being modeled. To meet this challenge, the authors apply the discrete event system specification (DEVS), a general modeling formalism invented for the formal description of a wide range of systems that vary in time. Using DEVS, developers can address the complexity of a biological model by subdividing it into a hierarchy of simpler submodels. Hierarchical design is a well-known strategy for software development in general. But the question remains, what type of decomposition should be used? The authors use the upper levels of a hierarchy to separate different functions or algorithms, and then dedicate lower levels to the partitioning of space. To illustrate the approach, they present a DEVS-based model that captures the 3D self-assembly of vesicle clusters and their role in the propagation of information between nerve cells.

Probing Microscopic Strain Interplay Due to Impurity Doping and Vicinal Growth and Its Effect on Pinning Landscape in YBCO Films

Vortex pinning by insertion of non-superconducting defects like BZO or BSO nanorods into the YBCO matrix is an effective means to enhance pinning since they self-assemble into columnar structures that provide strong pinning along the length of the flux-line. However, only limited control of their geometry is possible by current growth methods. To meet the requirements of applications that operate in magnetic fields of varying intensity or orientation, this work studies strain-mediated self-assembly of 3D pinning landscape through theoretical modeling as well as experimental exploration to achieve controllable growth BZO or BSO nanostructures in YBCO matrix films. The microstructure of BZO- and BSO-doped YBCO thin films was studied using transmission electron microscopy and the findings indicate that it is possible to produce a controllable defect landscape and improved critical current density with respect to different orientation of the magnetic field by manipulation of the strain relationships using vicinal substrates.

2D Space-Confined Synthesis of Few-Layer MoS2 Anchored on Carbon Nanosheet for Lithium-Ion Battery Anode.

A facile and scalable 2D spatial confinement strategy is developed for in situ synthesizing highly crystalline MoS2 nanosheets with few layers (≤5 layers) anchored on 3D porous carbon nanosheet networks (3D FL-MoS2@PCNNs) as lithium-ion battery anode. During the synthesis, 3D self-assembly of cubic NaCl particles is adopted to not only serve as a template to direct the growth of 3D porous carbon nanosheet networks, but also create a 2D-confined space to achieve the construction of few-layer MoS2 nanosheets robustly lain on the surface of carbon nanosheet walls. In the resulting 3D architecture, the intimate contact between the surfaces of MoS2 and carbon nanosheets can effectively avoid the aggregation and restacking of MoS2 as well as remarkably enhance the structural integrity of the electrode, while the conductive matrix of 3D porous carbon nanosheet networks can ensure fast transport of both electrons and ions in the whole electrode. As a result, this unique 3D architecture manifests an outstanding long-life cycling capability at high rates, namely, a specific capacity as large as 709 mAh g(-1) is delivered at 2 A g(-1) and maintains ∼95.2% even after 520 deep charge/discharge cycles. Apart from promising lithium-ion battery anode, this 3D FL-MoS2@PCNN composite also has immense potential for applications in other areas such as supercapacitor, catalysis, and sensors.

Silkworm cocoons by cylinders self-assembled from H-shaped alternating polymer brushes

We report a novel silkworm cocoon-like nanostructure based on the 3D hierarchical self-assembly of cylinders which are spontaneously formed by an H-shaped polymer brush comprising a disulfide-bridged spacer and two brushes with alternating PEG and PCL side chains. Crystalline of PCL between adjacent cylinders bridges cylinders.

Transcatheter based electromechanical mapping guided intramyocardial transplantation and in vivo tracking of human stem cell based three dimensional microtissues in the porcine heart

Stem cells have been repeatedly suggested for cardiac regeneration after myocardial infarction (MI). However, the low retention rate of single cell suspensions limits the efficacy of current therapy concepts so far. Taking advantage of three dimensional (3D) cellular self-assembly prior to transplantation may be beneficial to overcome these limitations. In this pilot study we investigate the principal feasibility of intramyocardial delivery of in-vitro generated stem cell-based 3D microtissues (3D-MTs) in a porcine model. 3D-MTs were generated from iron-oxide (MPIO) labeled human adipose-tissue derived mesenchymal stem cells (ATMSCs) using a modified hanging-drop method. Nine pigs (33 ± 2 kg) comprising seven healthy ones and two with chronic MI in the left ventricle (LV) anterior wall were included. The pigs underwent intramyocardial transplantation of 16 × 103 3D-MTs (1250 cells/MT; accounting for 2 × 107 single ATMSCs) into the anterior wall of the healthy pigs (n = 7)/the MI border zone of the infarcted (n = 2) of the LV using a 3D NOGA electromechanical mapping guided, transcatheter based approach. Clinical follow-up (FU) was performed for up to five weeks and in-vivo cell-tracking was performed using serial magnet resonance imaging (MRI). Thereafter, the hearts were harvested and assessed by PCR and immunohistochemistry. Intramyocardial transplantation of human ATMSC based 3D-MTs was successful in eight animals (88.8%) while one pig (without MI) died during the electromechanical mapping due to sudden cardiac-arrest. During FU, no arrhythmogenic, embolic or neurological events occurred in the treated pigs. Serial MRI confirmed the intramyocardial presence of the 3D-MTs by detection of the intracellular iron-oxide MPIOs during FU. Intramyocardial retention of 3D-MTs was confirmed by PCR analysis and was further verified on histology and immunohistochemical analysis. The 3D-MTs appeared to be viable, integrated and showed an intact micro architecture. We demonstrate the principal feasibility and safety of intramyocardial transplantation of in-vitro generated stem cell-based 3D-MTs. Multimodal cell-tracking strategies comprising advanced imaging and in-vitro tools allow for in-vivo monitoring and post-mortem analysis of transplanted 3D-MTs. The concept of 3D cellular self-assembly represents a promising application format as a next generation technology for cell-based myocardial regeneration.

Self-assembly of DNA nanoprisms with only two component strands

We report a symmetric design strategy to reduce the number of required DNA component strands in 3D self-assembly and have demonstrated this strategy by construction of a series of 3D DNA nanoprisms out of only two DNA strands.

The facile 3D self-assembly of porous iron hydroxide and oxide hierarchical nanostructures for removing dyes from wastewater

We report the template-free fabrication of 3D iron hydroxide hierarchical nanostructures through a simple and low-cost self-assembly process using a galvanic-cell reaction at room temperature. The existence of sodium sulfate in the reaction system is critical for formation of the iron hydroxide hierarchical nanostructures. X-ray diffraction analysis reveals that, after calcination, the iron hydroxide nanostructures can be changed into magnetic iron oxides. Relevant scanning electron microscopy and transmission electron microscopy images show that both of the flower-like nanostructures are composed of porous nanosheets. We also demonstrate that the two hierarchical nanostructures described above are negatively charged when dispersed in water. When used as adsorbents, they can selectively remove neutral dyes from wastewater with much higher capacities than those of conventional α-FeOOH and α-Fe2O3 nanoparticles, indicating great potential for use in water treatment.

3D DNA Self-Assembly Model for Minimum Control Sets Problem

In this paper, the minimum control sets(MCS) problem was solved by means of DNA self-assemble. We constructed the three-dimensional (3D) DNA molecular tiles and seed configuration to self-assemble. The results show that DNA self-assembly is an effective and feasible method for solving NP problem.

Size-, shape-, and assembly-controlled synthesis of Cu2−xSe nanocrystalsvia a non-injection phosphine-free colloidal method

In this paper, we report a facile, “green”, phosphine-free, low-cost, and non-injection method to obtain size-, shape-, and assembly-controllable Cu2−xSe nanocrystals which can be used as uniform building blocks. Different sizes of monodispersed Cu2−xSe nanocrystals were synthesized successfully by simply controlling the reaction temperature. The highly uniform Cu2−xSe nanocrystals can be well controlled from 4 to 20 nm when the temperature was set from 120 to 200 °C. By changing the ratios of CuSt2, oleic acid (OA), oleylamine (OAM), and selenium-octadecene (Se-ODE) precursor, Cu2−xSe nanocrystals with different shapes (hexagonal, elongated hexagonal bipyramid-shaped, trigonal pyramidal-shaped) and assembly behaviors (hexagonal Cu2−xSe nanodiscs with 1D, 2D, and 3D columnar self-assembly, elongated hexagonal bipyramid-shaped Cu2−xSe with 2D and 3D self-assembly, trigonal pyramidal-shaped Cu2−xSe nanocrystals with different arrays) were obtained indeed. Even though both OA and OAM were used as stabilizers to synthesize different shaped Cu2−xSe nanocrystals, FTIR results indicated that the surface of the as-synthesized nanocrystals was only capped by OAM. XRD studies confirmed that three different shapes of Cu2−xSe nanocrystals prepared with this non-injection method are all cubic berzelianite and well-crystallized. Current–voltage (I–V) behaviors of different shaped Cu2−xSe nanocrystals were measured and all found to have low resistivities.

Self-Assembled Peptide Architecture with a Tooth Shape: Folding into Shape

Molecular self-assembly is the spontaneous association of molecules into structured aggregates by which nature builds complex functional systems. While numerous examples have focused on 2D self-assembly to understand the underlying mechanism and mimic this process to create artificial nano- and microstructures, limited progress has been made toward 3D self-assembly on the molecular level. Here we show that a helical β-peptide foldamer, an artificial protein fragment, with well-defined secondary structure self-assembles to form an unprecedented 3D molecular architecture with a molar tooth shape in a controlled manner in aqueous solution. Powder X-ray diffraction analysis, combined with global optimization and Rietveld refinement, allowed us to propose its molecular arrangement. We found that four individual left-handed helical monomers constitute a right-handed superhelix in a unit cell of the assembly, similar to that found in the supercoiled structure of collagen.

Application of 3D DNA Self-Assembly for Graph Coloring Problem

Application of 3D DNA Self-Assembly for Graph Coloring Problem

Using Magnetic Levitation for Three Dimensional Self‐Assembly

Magnetic levitation (MagLev) enables 3D self-assembly of diamagnetic objects with control over many aspects of position and orientation. This work demonstrates the ability of MagLev to position and align components, such as mirrors, filters, lenses, and soft objects, without mechanical support. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Label-Free Optical Characterization Methods for Detecting Amine Silanization-Driven Gold Nanoparticle Self-Assembly

Fluorescence lifetime correlation spectroscopy (FLCS) is presented as a single-step label-free detection method for probing the amine silanization-driven spontaneous 3D self-assembly of freestanding gold nanoparticles (GNPs) in solution. Unlike the conventional methods of studying self-assembly, for example, UV-vis spectroscopy and electron microscopy, FLCS utilizes the intrinsic gold fluorescence. The significance of this approach is to amalgamate the measurement of optical and hydrodynamic size properties simultaneously to achieve a more coherent description of the self-assembly pathway. GNP self-assembly has two-stage kinetics. Electrostatic interaction drives the initial amine silanization, and this is followed by siloxane bond formation between hydrolyzed ethoxy groups of GNP-attached APTES, resulting in the formation of micrometer-sized superstructures. The self-assembly has resulted in a 5-fold increase in the fluorescence lifetime (FL), and the FLCS study has shown an 8- to 10-fold increase in the diffusion coefficient using the pure diffusion model. This result is consistent with the transmission electron microscopy (TEM) observation, which shows a few hundred fold increase in the diameter due to assembly formation by the GNPs.