Zeitschriftenartikel: „Dynamic hierarchical self-Assembly“

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Zhang, Huan, Fan Pan und Shiben Li. „Self-Assembly of Lipid Molecules under Shear Flows: A Dissipative Particle Dynamics Simulation Study“. Biomolecules 13, Nr. 9 (07.09.2023): 1359. http://dx.doi.org/10.3390/biom13091359.

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The self-assembly of lipid molecules in aqueous solution under shear flows was investigated using the dissipative particle dynamics simulation method. Three cases were considered: zero shear flow, weak shear flow and strong shear flow. Various self-assembled structures, such as double layers, perforated double layers, hierarchical discs, micelles, and vesicles, were observed. The self-assembly behavior was investigated in equilibrium by constructing phase diagrams based on chain lengths. Results showed the remarkable influence of chain length, shear flow and solution concentration on the self-assembly process. Furthermore, the self-assembly behavior of lipid molecules was analyzed using the system energy, particle number and shape factor during the dynamic processes, where the self-assembly pathways were observed and analyzed for the typical structures. The results enhance our understanding of biomacromolecule self-assembly in a solution and hold the potential for applications in biomedicine.

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Shi, Lijuan, Fenglin Liu, Tingting Liu, Jingsi Chen, Shaobo Xu und Hongbo Zeng. „Reversible fabrication and self-assembly of a gemini supra-amphiphile driven by dynamic covalent bonds“. Soft Matter 14, Nr. 29 (2018): 5995–6000. http://dx.doi.org/10.1039/c8sm01239c.

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Freeman, Ronit, Ming Han, Zaida Álvarez, Jacob A. Lewis, James R. Wester, Nicholas Stephanopoulos, Mark T. McClendon et al. „Reversible self-assembly of superstructured networks“. Science 362, Nr. 6416 (04.10.2018): 808–13. http://dx.doi.org/10.1126/science.aat6141.

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Soft structures in nature, such as protein assemblies, can organize reversibly into functional and often hierarchical architectures through noncovalent interactions. Molecularly encoding this dynamic capability in synthetic materials has remained an elusive goal. We report on hydrogels of peptide-DNA conjugates and peptides that organize into superstructures of intertwined filaments that disassemble upon the addition of molecules or changes in charge density. Experiments and simulations demonstrate that this response requires large-scale spatial redistribution of molecules directed by strong noncovalent interactions among them. Simulations also suggest that the chemically reversible structures can only occur within a limited range of supramolecular cohesive energies. Storage moduli of the hydrogels change reversibly as superstructures form and disappear, as does the phenotype of neural cells in contact with these materials.

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Wu, Ruirui, Shunfa Gong, Lifang Wu, Hailong Yu, Qiuju Han und Wenzhi Wu. „Laser-induced crystal growth observed in CsPbBr₃ perovskite nanoplatelets“. Physical Chemistry Chemical Physics 24, Nr. 14 (2022): 8303–10. http://dx.doi.org/10.1039/d1cp05874f.

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Laser irradiation is used to induce CsPbBr3 NPLs reshaping and morphology control. A hierarchical self-assembly process occurs in the CsPbBr3 NPLs. The crystal growth relies on seeking dynamic balance between heat dissipation and accumulation.

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Melaku, Ashenafi Zeleke, Wei-Tsung Chuang, Yeong-Tarng Shieh, Chih-Wei Chiu, Duu-Jong Lee, Juin-Yih Lai und Chih-Chia Cheng. „Programmed exfoliation of hierarchical graphene nanosheets mediated by dynamic self-assembly of supramolecular polymers“. Materials Chemistry Frontiers 5, Nr. 18 (2021): 6998–7011. http://dx.doi.org/10.1039/d1qm00810b.

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Programming hierarchical graphene nanosheets by two-step exfoliation of graphite combined with an adenine-functionalized telechelic polymer in o-dichlorobenzene can achieve highly stable graphene nanosheets with wide-range tunable layer thickness.

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Suárez-Picado, Esteban, Maëva Coste, Jean-Yves Runser, Mathieu Fossépré, Alain Carvalho, Mathieu Surin, Loïc Jierry und Sébastien Ulrich. „Hierarchical Self-Assembly and Multidynamic Responsiveness of Fluorescent Dynamic Covalent Networks Forming Organogels“. Biomacromolecules 23, Nr. 1 (15.12.2021): 431–42. http://dx.doi.org/10.1021/acs.biomac.1c01389.

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Zeng, Chunyan, Chen Gao, Li Yuan, Tao Liang, Ruisong Yang, Wei Zhang und Song Nie. „Water Evaporation-Induced Self-Assembly of Hierarchical CuO/MnO2 Composite Nanospheres and their Applications in Lithium-Ion Batteries“. Nano 12, Nr. 02 (Februar 2017): 1750022. http://dx.doi.org/10.1142/s1793292017500229.

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In this paper, hierarchical CuO/MnO2 composite hollow nanospheres have been successfully fabricated by water evaporation-induced self-assembly through a redox transformation reaction between Cu2O nanospheres and KMnO4 solution at 120[Formula: see text]C for 6[Formula: see text]h, followed by removing the residual Cu2O cores with ammonia hydroxide solution. The outstanding feature of this method is that the reaction system is in a dynamic environment due to the evaporation of the solvent water, which benefits the self-assembly of nanostructures to form hierarchical structures. Both Kirkendall effect and Ostwald ripening mechanism are suggested to be responsible for the formation of the hierarchical CuO/MnO2 nanocomposites according to the characterization results. The electrochemical properties of the products were studied, and the results show that the hierarchical CuO/MnO2 hollow nanospheres exhibit high capacity and good rate performance (a stable capacity of about 480[Formula: see text]mAh[Formula: see text]g[Formula: see text] after 80 cycles of variable charging rate), which is probably attributed to the hierarchical hollow nanostructures.

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Bystrov, Vladimir, Ilya Likhachev, Sergey Filippov und Ekaterina Paramonova. „Molecular Dynamics Simulation of Self-Assembly Processes of Diphenylalanine Peptide Nanotubes and Determination of Their Chirality“. Nanomaterials 13, Nr. 13 (21.06.2023): 1905. http://dx.doi.org/10.3390/nano13131905.

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In this work, we further developed a new approach for modeling the processes of the self-assembly of complex molecular nanostructures using molecular dynamics methods; in particular, using a molecular dynamics manipulator. Previously, this approach was considered using the example of the self-assembly of a phenylalanine helical nanotube. Now, a new application of the algorithm has been developed for implementing a similar molecular dynamic self-assembly into helical structures of peptide nanotubes (PNTs) based on other peptide molecules—namely diphenylalanine (FF) molecules of different chirality L-FF and D-FF. In this work, helical nanotubes were assembled from linear sequences of FF molecules with these initially different chiralities. The chirality of the obtained nanotubes was calculated by various methods, including calculation by dipole moments. In addition, a statistical analysis of the results obtained was performed. A comparative analysis of the structures of nanotubes was also performed using the method of visual differential analysis. It was found that FF PNTs obtained by the MD self-assembly method form helical nanotubes of different chirality. The regimes that form nanotubes of right chirality D from initial L-FF dipeptides and nanotubes of left chirality L from D-FF dipeptides are revealed. This corresponds to the law of changing the sign of the chirality of molecular helical structures as the level of their hierarchical organization becomes more complicated.

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Coste, Maëva, Esteban Suárez-Picado und Sébastien Ulrich. „Hierarchical self-assembly of aromatic peptide conjugates into supramolecular polymers: it takes two to tango“. Chemical Science 13, Nr. 4 (2022): 909–33. http://dx.doi.org/10.1039/d1sc05589e.

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The dynamic combination of aromatics and peptides yields functional supramolecular biopolymers which self-assemble hierarchically and adapt through non-covalent interactions and/or reversible covalent reactions.

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Rakotondradany, Felaniaina, Hanadi Sleiman und M. A. Whitehead. „Hydrogen-bond self-assembly of DNA-base analogues — Experimental results“. Canadian Journal of Chemistry 87, Nr. 5 (Mai 2009): 627–39. http://dx.doi.org/10.1139/v09-028.

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A novel biomimetic DNA analogue with fluorescence has been synthesized to generate functional supramolecular architectures. Experimental studies show that triaminopyrimidine nucleoside (2) undergoes a sterically controlled self-assembly into hydrogen-bonded linear tapes and hexameric rosettes. Self-association of the hydrogen-bonded triaminopyrimidine–cyanuric acid complex into elongated, rodlike nanostructures was shown by dynamic light scattering and transmission electron microscopy, suggesting hierarchical formation of higher-order, π-stacked assemblies. The hydrogen-bond self-assembly of the DNA analogue decreased the fluorescence of the nucleosides. This guest-induced fluorescence quenching can be used to develop DNA-hybridization probes. MM+ molecular modelling and semi-empirical molecular orbital PM3 calculations (1) predicted the incorporation of triaminopyrimidine nucleoside into new types of artificial DNA strands and triplex formation with natural, complementary DNA strands containing thymine (1).

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He, Ao-Lin, Zhou Wang und Rui-Jiang Liu. „Nano-Graphene Enclosed Multi Nitrogen: Dynamic Hierarchical Self-Assemble Property for Lithium Ion Storage“. Journal of Nanoscience and Nanotechnology 20, Nr. 5 (01.05.2020): 2675–88. http://dx.doi.org/10.1166/jnn.2020.17435.

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Led to significant capacity improvement to 1800 mA/h after 100 cycles for nano-graphene-N4, which is the first report for a carbonaceous materials anode. In addition, the doping level, id est, number of nitrogen atoms, had a significant influence on the molecular self-assembled structures through hierarchical self-assembly. As the nitrogen concentration increased, the d-space between the nanosheets increased from 3.4 to 4.3. The capacity of the nano-graphene increased greatly from 500 mAh/g for nano-graphene without N-doping to 1800 mAh/g for nano-graphene with nanographene-N4, indicating that the capacity is related to the structures, and was defined and the relationship between performance and structure was determined.

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Eghtesadi, Seyed Ali, Marjan Alsadat Kashfipour, Xinyu Sun, Wei Zhang, Robert Scott Lillard, Stephen Z. D. Cheng und Tianbo Liu. „Hierarchical self-assembly of zwitterionic dendrimer–anionic surfactant complexes into multiple stimuli-responsive dynamic nanotubes“. Nanoscale 10, Nr. 3 (2018): 1411–19. http://dx.doi.org/10.1039/c7nr07950h.

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Zwitterionic materials attract a wide range of attention due to their unique molecular structures and properties. We showed that they could be an effective tool to design well-ordered nanostructures with stimuli-responsive character through bottom-up approaches.

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Liu, Jonathan, C. Wyatt Shields, Oluwatosin Omofoye und Gabriel P. Lopez. „Programmable Anisotropic Microparticles for Self-Assembly Applications“. MRS Proceedings 1622 (2014): 55–60. http://dx.doi.org/10.1557/opl.2014.38.

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AbstractColloids with anisotropic shape and properties can enable the assembly of advanced materials otherwise not attainable by microfabrication. In this study, we present a convenient method using common microfabrication tools to generate a diverse array of non-spherical microparticles with well-defined shapes, sizes, electromagnetic properties for self-assembly applications. Projection photolithography onto SU-8 photoresist enabled the production of large aspect ratio microparticles such as cubes, cuboids, cylinders, hexagonal prisms, and parallelepipeds. We characterized these particles to confirm their anisotropic shape and size monodispersity. Fluorescent stains (e.g., Nile red) were mixed into the photoresist prepolymer to enhance the visualization of particle orientation. Particles designed for passive self-assembly were prepared by conventional photolithographic techniques. Particles designed for active assembly were then decorated with metallic patches in precise locations along the surface (e.g., top, side or multiple sides) using electron beam metal evaporation. This metal deposition process can enable orientational control of particles during their assembly in directed fields. After fabrication, large particles (e.g., 1,000 µm3) were released from the substrate via gentle sheer forces, whereas small particles (e.g., 10 µm3) were released by the dissolution of a sacrificial layer underneath the SU-8. Suspending the particles in water with surfactant (or other suitable solvents) provided amenable conditions for their assembly in static or dynamic systems. These conventional methods have the potential to catalyze new research in the fabrication and assembly of anisotropic patchy particles with controllable properties for the hierarchical development of self-assembled micromirrors, biosensors, and photonic crystals as examples.

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Chen, Huaijun, Guang Yang, Ensong Zhang, Qiqige Du, Rongying Liu, Libin Wu, Yingle Feng und Guosong Chen. „Hierarchical self-assembly of native protein and its dynamic regulation directed by inducing ligand with oligosaccharide“. European Polymer Journal 135 (Juli 2020): 109871. http://dx.doi.org/10.1016/j.eurpolymj.2020.109871.

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Liang, Binbin, Yuhang Miao, Liying Zhao, Lan Fang und Dawei Deng. „A dandelion-like nanomedicine via hierarchical self-assembly for synergistic chemotherapy and photo-dynamic cancer therapy“. Nanomedicine: Nanotechnology, Biology and Medicine 49 (April 2023): 102660. http://dx.doi.org/10.1016/j.nano.2023.102660.

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Szustakiewicz, Piotr, Natalia Kowalska, Maciej Bagiński und Wiktor Lewandowski. „Active Plasmonics with Responsive, Binary Assemblies of Gold Nanorods and Nanospheres“. Nanomaterials 11, Nr. 9 (03.09.2021): 2296. http://dx.doi.org/10.3390/nano11092296.

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Self-assembly of metal nanoparticles has applications in the fabrication of optically active materials. Here, we introduce a facile strategy for the fabrication of films of binary nanoparticle assemblies. Dynamic control over the configuration of gold nanorods and nanospheres is achieved via the melting of bound and unbound fractions of liquid-crystal-like nanoparticle ligands. This approach provides a route for the preparation of hierarchical nanoparticle superstructures with applications in reversibly switchable, visible-range plasmonic technologies.

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Yue, Yang, und Guang Ping Zeng. „A Component Model Supporting Dynamic Evolution of Internetware“. Key Engineering Materials 467-469 (Februar 2011): 956–61. http://dx.doi.org/10.4028/www.scientific.net/kem.467-469.956.

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Aiming at the forward topics of self-adapting Internetware, relying on the practical software engineering technology and previous research achievements of tackling key problems of SoftMan, the paper puts forward a novel component model ——SMC(SoftMan Component), which processes reflectivity, opening, adapting and supporting nested assembly and self-adjusting its internal architecture. Furthermore, the basic design specifications of APIs are described in detail. By the special structure of Component Body, SMC forms a hierarchical management domain which is of explicit constraint of father-child between component and its children, and thus it flexibly integrates control mechanisms for sub-components, such as interface introspection, lifecycle, interaction binding, dynamic configuration, etc., into its pluggable controllers so as to be endowed with the ability to change its behavior and architecture when the application must evolve to cope with user requirements and new context. Initial experiments demonstrate that SMC can give effective support for dynamic reconfiguration during running, and it takes on own technical characteristics compared with other component models.

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Uskoković, V., Z. Castiglione, P. Cubas, L. Zhu, W. Li und S. Habelitz. „Zeta-potential and Particle Size Analysis of Human Amelogenins“. Journal of Dental Research 89, Nr. 2 (29.12.2009): 149–53. http://dx.doi.org/10.1177/0022034509354455.

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The developing enamel matrix is a highly dynamic system mainly composed of the full-length amelogenin and its proteolytic cleavage products. In this study, size, zeta-potential, and the isoelectric points of nanoparticles of the recombinant full-length human amelogenin (rH174) and two proteolytic products (rH163 and rH146) were analyzed by dynamic light-scattering and electrokinetic measurements. We tested the hypothesis that zeta-potential may be used as a control parameter in directing the self-assembly of amelogenins. Extensive aggregation of amelogenin molecules with the particle size reaching about one micron occurred at a mildly acidic to neutral pH, and coincided with the red shift of the internal fluorescence. Zeta-potential was between ± 15 mV in the same pH range, indicating that amelogenin aggregation occurred when surface potentials were minimal. This suggests that electrostatic interactions may be another crucial factor, aside from hydrophobic interaction, in the aggregation and hierarchical assembly of spherical particles of amelogenins into supramolecular structures of a higher order.

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Lin, Fengcai, Wenyan Lin, Jingwen Chen, Chenyi Sun, Xiaoxiao Zheng, Yanlian Xu, Beili Lu, Jipeng Chen und Biao Huang. „Tannic Acid-Induced Gelation of Aqueous Suspensions of Cellulose Nanocrystals“. Polymers 15, Nr. 20 (15.10.2023): 4092. http://dx.doi.org/10.3390/polym15204092.

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Nanocellulose hydrogels are a crucial category of soft biomaterials with versatile applications in tissue engineering, artificial extracellular matrices, and drug-delivery systems. In the present work, a simple and novel method, involving the self-assembly of cellulose nanocrystals (CNCs) induced by tannic acid (TA), was developed to construct a stable hydrogel (SH-CNC/TA) with oriented porous network structures. The gelation process is driven by the H-bonding interaction between the hydroxyl groups of CNCs and the catechol groups of TA, as substantiated by the atoms in molecules topology analysis and FTIR spectra. Interestingly, the assembled hydrogels exhibited a tunable hierarchical porous structure and mechanical moduli by varying the mass ratio of CNCs to TA. Furthermore, these hydrogels also demonstrate rapid self-healing ability due to the dynamic nature of the H-bond. Additionally, the structural stability of the SH-CNC/TA hydrogel could be further enhanced and adjusted by introducing coordination bonding between metal cations and TA. This H-bonding driven self-assembly method may promote the development of smart cellulose hydrogels with unique microstructures and properties for biomedical and other applications.

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Liu, Yi, Weili Qiang, Taotao Ji, Mu Zhang, Mingrun Li, Jinming Lu und Yi Liu. „Uniform hierarchical MFI nanosheets prepared via anisotropic etching for solution-based sub–100-nm-thick oriented MFI layer fabrication“. Science Advances 6, Nr. 7 (Februar 2020): eaay5993. http://dx.doi.org/10.1126/sciadv.aay5993.

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Zeolite nanosheets have shown unprecedented opportunities for a wide range of applications, yet developing facile methods for fabrication of uniform zeolite nanosheets remains a great challenge. Here, a facile approach involving anisotropic etching with an aqueous solution of tetrapropylammonium hydroxide (TPAOH) was developed for preparing uniform high–aspect ratio hierarchical MFI nanosheets. In addition, the mechanism associated with the formation of MFI nanosheets was proposed. In the next step, a dynamic air-liquid interface–assisted self-assembly method and single-mode microwave heating were used for b-oriented MFI nanosheets monolayer deposition and controlled in-plane solution-based epitaxial growth, respectively, ensuring the formation of well-intergrown b-oriented MFI layers with sub–100-nm thickness. Moreover, our study indicated that b-oriented ultrathin MFI layers could be fabricated on diverse substrates demonstrating excellent anticorrosion capacity, ionic sieving properties, and n-/i-butane isomer separation performance.

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Hamada, Shogo, Kenneth Gene Yancey, Yehudah Pardo, Mingzhe Gan, Max Vanatta, Duo An, Yue Hu et al. „Dynamic DNA material with emergent locomotion behavior powered by artificial metabolism“. Science Robotics 4, Nr. 29 (10.04.2019): eaaw3512. http://dx.doi.org/10.1126/scirobotics.aaw3512.

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Metabolism is a key process that makes life alive—the combination of anabolism and catabolism sustains life by a continuous flux of matter and energy. In other words, the materials comprising life are synthesized, assembled, dissipated, and decomposed autonomously in a controlled, hierarchical manner using biological processes. Although some biological approaches for creating dynamic materials have been reported, the construction of such materials by mimicking metabolism from scratch based on bioengineering has not yet been achieved. Various chemical approaches, especially dissipative assemblies, allow the construction of dynamic materials in a synthetic fashion, analogous to part of metabolism. Inspired by these approaches, here, we report a bottom-up construction of dynamic biomaterials powered by artificial metabolism, representing a combination of irreversible biosynthesis and dissipative assembly processes. An emergent locomotion behavior resembling a slime mold was programmed with this material by using an abstract design model similar to mechanical systems. Dynamic properties, such as autonomous pattern generation and continuous polarized regeneration, enabled locomotion along the designated tracks against a constant flow. Furthermore, an emergent racing behavior of two locomotive bodies was achieved by expanding the program. Other applications, including pathogen detection and hybrid nanomaterials, illustrated further potential use of this material. Dynamic biomaterials powered by artificial metabolism could provide a previously unexplored route to realize “artificial” biological systems with regenerating and self-sustaining characteristics.

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Duan, Ming, Qingqing Tang, Manlin Wang, Mengjuan Luo, Shenwen Fang, Xiujun Wang, Peng Shi und Yan Xiong. „Preparation of poly-dopamine-silk fibroin sponge and its dye molecular adsorption“. Water Science and Technology 82, Nr. 11 (20.10.2020): 2353–65. http://dx.doi.org/10.2166/wst.2020.502.

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Abstract This paper proposes a process for fabricating a poly-dopamine-silk fibroin sponge (PDA-SF) by using dopamine self-assembly and coating the skeleton of a silk fibroin sponge. The PDA-SF sponge was characterized by SEM, TEM, XPS, XRD and FT-IR. It was found that the sponge exhibits sheet structures with a pore size of 60 ± 20 μm and poly-dopamine adhered to the surface of pure silk fibroin through noncovalent bond forces. With a hierarchical porous structure, the derived sponge provides fast flow channels and abundant active sites, which will benefit the diffusion and removal of cationic dyes. Batch adsorption and dynamic adsorption of crystal violet (CV) were studied. The batch adsorption capacity of the PDA-SF sponge for CV increased with its PDA content. Under a dynamic adsorption mode, the adsorption efficiency of the PDA-SF sponge for CV (5 mg/L, 200 mL) can reach up to 98.2% after 12 min, whereas it is only 90.2% under stationary mode after 72 h. Furthermore, the sponge shows an outstanding smart adsorption performance. More importantly, the composite sponge still keeps high separation and adsorption efficiencies after 20 cycles, and the appearance remains good.

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Likhachev, I. V., und V. S. Bystrov. „Assembly of a Phenylalanine Nanotube by the use of Molecular Dynamics Manipulator“. Mathematical Biology and Bioinformatics 16, Nr. 2 (27.07.2021): 244–55. http://dx.doi.org/10.17537/2021.16.244.

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Studies of the processes of self-organization and self-assembly of various complexly organized (including spiral) structures based on amino acids intensively carried out in recent years. Various methods of molecular modeling, including molecular dynamics (MD) methods, are developed. In this paper, we propose a new approach for a relatively simple technique for conducting MD simulation (MDS) of various molecular nanostructures, determining the trajectory of the MD run and forming the final structure: a molecular dynamic manipulator (MD manipulator). It is an imitation of the operation of an existing or imaginary device or structure by applying force to the existing initial structure in order to obtain a new final structure, having the same chemical composition, but with a different geometry (topology). The PUMA-CUDA software package was applied as the main MD modeling program, which uses the physics of the PUMA software package, developed by the laboratory headed by N.K. Balabaev. Using this MDS tool, you can investigate the formation of helical structures from a linear sequence of any amino acids variation. As an example, the applicability of the developed algorithm for assembling nanotubes from linear phenylalanine (Phe) chains of different chirality (left L-Phe and right D-Phe) is considered by including additional force effects in the molecular dynamics simulation program for these structures. During the MD run, the applied actions, which are the same for the left and right helices of the formed nanotubes, lead the system to an α-helix structure. The work was carried out in an interactive mode using a number of additional programs, incl. trajectory analyzer program MD (TAMD). As a result, the modes that are most adequate for the formation of nanotubes of the right chirality D from the initial L-Phe monomer and nanotubes of the left chirality L from the D-Phe amino acid monomer were determined. The results obtained were compared with data from other works on modeling similar nanotubes of different chirality and experimental data. These are fully in line with the law of change in sign of chirality of molecular structures with complication of their hierarchical level of organization. The molecular animation of the assembly of a left-chiral nanotube from D-monomers is freely available at: http://lmd.impb.ru/Supplementary/PHE.avi.

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Bercea, Maria. „Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities“. Polymers 14, Nr. 12 (11.06.2022): 2365. http://dx.doi.org/10.3390/polym14122365.

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Hydrogels, as interconnected networks (polymer mesh; physically, chemically, or dynamic crosslinked networks) incorporating a high amount of water, present structural characteristics similar to soft natural tissue. They enable the diffusion of different molecules (ions, drugs, and grow factors) and have the ability to take over the action of external factors. Their nature provides a wide variety of raw materials and inspiration for functional soft matter obtained by complex mechanisms and hierarchical self-assembly. Over the last decade, many studies focused on developing innovative and high-performance materials, with new or improved functions, by mimicking biological structures at different length scales. Hydrogels with natural or synthetic origin can be engineered as bulk materials, micro- or nanoparticles, patches, membranes, supramolecular pathways, bio-inks, etc. The specific features of hydrogels make them suitable for a wide variety of applications, including tissue engineering scaffolds (repair/regeneration), wound healing, drug delivery carriers, bio-inks, soft robotics, sensors, actuators, catalysis, food safety, and hygiene products. This review is focused on recent advances in the field of bioinspired hydrogels that can serve as platforms for life-science applications. A brief outlook on the actual trends and future directions is also presented.

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Cartwright, Julyan H. E., und Antonio G. Checa. „The dynamics of nacre self-assembly“. Journal of The Royal Society Interface 4, Nr. 14 (08.12.2006): 491–504. http://dx.doi.org/10.1098/rsif.2006.0188.

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We show how nacre and pearl construction in bivalve and gastropod molluscs can be understood in terms of successive processes of controlled self-assembly from the molecular- to the macro-scale. This dynamics involves the physics of the formation of both solid and liquid crystals and of membranes and fluids to produce a nanostructured hierarchically constructed biological composite of polysaccharides, proteins and mineral, whose mechanical properties far surpass those of its component parts.

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Fernández-Rico, Carla, und Roel P. A. Dullens. „Hierarchical self-assembly of polydisperse colloidal bananas into a two-dimensional vortex phase“. Proceedings of the National Academy of Sciences 118, Nr. 33 (13.08.2021): e2107241118. http://dx.doi.org/10.1073/pnas.2107241118.

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Self-assembly of microscopic building blocks into highly ordered and functional structures is ubiquitous in nature and found at all length scales. Hierarchical structures formed by colloidal building blocks are typically assembled from monodisperse particles interacting via engineered directional interactions. Here, we show that polydisperse colloidal bananas self-assemble into a complex and hierarchical quasi–two-dimensional structure, called the vortex phase, only due to excluded volume interactions and polydispersity in the particle curvature. Using confocal microscopy, we uncover the remarkable formation mechanism of the vortex phase and characterize its exotic structure and dynamics at the single-particle level. These results demonstrate that hierarchical self-assembly of complex materials can be solely driven by entropy and shape polydispersity of the constituting particles.

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Prybytak, P., W. J. Frith und D. J. Cleaver. „Hierarchical self-assembly of chiral fibres from achiral particles“. Interface Focus 2, Nr. 5 (28.03.2012): 651–57. http://dx.doi.org/10.1098/rsfs.2011.0104.

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We investigate, by molecular dynamics simulation, the behaviour of discotic particles in a solvent of Lennard-Jones spheres. When chromonic disc–sphere interactions are imposed on these systems, three regimes of self-assembly are observed. At moderate temperatures, numerous short threads of discs develop, but these threads remain isolated from one another. Quenching to low temperatures, alternatively, causes all of the discs to floc into a single extended aggregate which typically comprises several distinct sections and contains numerous packing defects. For a narrow temperature range between these regimes, however, defect-free chiral fibres are found to freely self-assemble. The spontaneous chirality of these fibres results from frustration between the hexagonal packing and interdigitation of neighbouring threads, the pitch being set by the particle shape. This demonstration of aggregate-wide chirality emerging owing to packing alone is pertinent to many biological and synthetic hierarchically self-assembling systems.

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Baschek, Johanna E., Heinrich C. R Klein und Ulrich S. Schwarz. „Stochastic dynamics of virus capsid formation: direct versus hierarchical self-assembly“. BMC Biophysics 5, Nr. 1 (2012): 22. http://dx.doi.org/10.1186/2046-1682-5-22.

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Yuan, Chengqian, Shukun Li, Qianli Zou, Ying Ren und Xuehai Yan. „Multiscale simulations for understanding the evolution and mechanism of hierarchical peptide self-assembly“. Physical Chemistry Chemical Physics 19, Nr. 35 (2017): 23614–31. http://dx.doi.org/10.1039/c7cp01923h.

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Multiscale molecular simulations that combine and systematically link several hierarchies can provide insights into the evolution and dynamics of hierarchical peptide self-assembly from the molecular level to the mesoscale.

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Wang, Shuang, Xiaolin Xie, Zhi Chen, Ningning Ma, Xue Zhang, Kai Li, Chao Teng, Yonggang Ke und Ye Tian. „DNA-Grafted 3D Superlattice Self-Assembly“. International Journal of Molecular Sciences 22, Nr. 14 (15.07.2021): 7558. http://dx.doi.org/10.3390/ijms22147558.

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The exploitation of new methods to control material structure has historically been dominating the material science. The bottom-up self-assembly strategy by taking atom/molecule/ensembles in nanoscale as building blocks and crystallization as a driving force bring hope for material fabrication. DNA-grafted nanoparticle has emerged as a “programmable atom equivalent” and was employed for the assembly of hierarchically ordered three-dimensional superlattice with novel properties and studying the unknown assembly mechanism due to its programmability and versatility in the binding capabilities. In this review, we highlight the assembly strategies and rules of DNA-grafted three-dimensional superlattice, dynamic assembly by different driving factors, and discuss their future applications.

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Lawes, Patrick, Mauro Boero, Rabei Barhoumi, Svetlana Klyatskaya, Mario Ruben und Jean-Pierre Bucher. „Hierarchical Self-Assembly and Conformation of Tb Double-Decker Molecular Magnets: Experiment and Molecular Dynamics“. Nanomaterials 13, Nr. 15 (01.08.2023): 2232. http://dx.doi.org/10.3390/nano13152232.

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Nanostructures, fabricated by locating molecular building blocks in well-defined positions, for example, on a lattice, are ideal platforms for studying atomic-scale quantum effects. In this context, STM data obtained from self-assembled Bis(phthalocyaninato) Terbium (III) (TbPc2) single-molecule magnets on various substrates have raised questions about the conformation of the TbPc2 molecules within the lattice. In order to address this issue, molecular dynamics simulations were carried out on a 2D assembly of TbPc2 molecules. The calculations are in excellent agreement with the experiment, and thus improve our understanding of the self-assembly process. In particular, the calculated electron density of the molecular assembly compares well with STM contrast of self-assembled TbPc2 on Au(111), simultaneously providing the conformation of the two Pc ligands of the individual double-decker molecule. This approach proves valuable in the identification of the STM contrast of LnPc2 layers and could be used in similar cases where it is difficult to interpret the STM images of an assembly of molecular complexes.

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Yeo, Giselle C., Anna Tarakanova, Clair Baldock, Steven G. Wise, Markus J. Buehler und Anthony S. Weiss. „Subtle balance of tropoelastin molecular shape and flexibility regulates dynamics and hierarchical assembly“. Science Advances 2, Nr. 2 (05.02.2016): e1501145. http://dx.doi.org/10.1126/sciadv.1501145.

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The assembly of the tropoelastin monomer into elastin is vital for conferring elasticity on blood vessels, skin, and lungs. Tropoelastin has dual needs for flexibility and structure in self-assembly. We explore the structure-dynamics-function interplay, consider the duality of molecular order and disorder, and identify equally significant functional contributions by local and global structures. To study these organizational stratifications, we perturb a key hinge region by expressing an exon that is universally spliced out in human tropoelastins. We find a herniated nanostructure with a displaced C terminus and explain by molecular modeling that flexible helices are replaced with substantial β sheets. We see atypical higher-order cross-linking and inefficient assembly into discontinuous, thick elastic fibers. We explain this dysfunction by correlating local and global structural effects with changes in the molecule’s assembly dynamics. This work has general implications for our understanding of elastomeric proteins, which balance disordered regions with defined structural modules at multiple scales for functional assembly.

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Maeda, Matsuhiro, Ruri Nakayama, Steven De Feyter, Yoshito Tobe und Kazukuni Tahara. „Hierarchical two-dimensional molecular assembly through dynamic combination of conformational states at the liquid/solid interface“. Chemical Science 11, Nr. 34 (2020): 9254–61. http://dx.doi.org/10.1039/d0sc03163a.

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Self-sorting of multiple building blocks for correctly positioning molecules through orthogonal recognition is a promising strategy for construction of a hierarchical self-assembled molecular network (SAMN) on a surface.

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Kolay, Sarita, Dipankar Bain, Subarna Maity, Aarti Devi, Amitava Patra und Rodolphe Antoine. „Self-Assembled Metal Nanoclusters: Driving Forces and Structural Correlation with Optical Properties“. Nanomaterials 12, Nr. 3 (05.02.2022): 544. http://dx.doi.org/10.3390/nano12030544.

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Studies on self-assembly of metal nanoclusters (MNCs) are an emerging field of research owing to their significant optical properties and potential applications in many areas. Fabricating the desired self-assembly structure for specific implementation has always been challenging in nanotechnology. The building blocks organize themselves into a hierarchical structure with a high order of directional control in the self-assembly process. An overview of the recent achievements in the self-assembly chemistry of MNCs is summarized in this review article. Here, we investigate the underlying mechanism for the self-assembly structures, and analysis reveals that van der Waals forces, electrostatic interaction, metallophilic interaction, and amphiphilicity are the crucial parameters. In addition, we discuss the principles of template-mediated interaction and the effect of external stimuli on assembly formation in detail. We also focus on the structural correlation of the assemblies with their photophysical properties. A deep perception of the self-assembly mechanism and the degree of interactions on the excited state dynamics is provided for the future synthesis of customizable MNCs with promising applications.

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Likhachev, I. V., V. S. Bystrov und S. V. Filippov. „Assembly of a Diphenylalanine Peptide Nanotube by Molecular Dynamics Methods“. Mathematical Biology and Bioinformatics 18, Nr. 1 (30.06.2023): 251–66. http://dx.doi.org/10.17537/2023.18.251.

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The paper develops an approach to modeling the processes of self-assembly of complex molecular nanostructures by molecular dynamics methods using a molecular dynamics manipulator. Previously, this approach was considered using the example of assembling a phenylalanine helical nanotube from a linear set of chains of phenylalanine (F) molecules of different chirality: left-handed L-F and right-handed D-F chirality L-FF and D-FF. The process of self-assembly of dipeptide chains into helical structures of nanotubes is an imitation of applying certain forces to the existing initial linear structure in order to obtain the final structure of the same chemical composition, but with a different helical geometry. The PUMA-CUDA molecular dynamics simulation software package was used as the main software. Using this tool, one can investigate the formation of helical structures from a linear sequence of any amino acids. A comparative analysis of the structures of nanotubes obtained by assembling by molecular dynamics methods and by their experimental self-assembly was performed using the method of visual differential analysis. It has been established that the obtained data correspond to the law of the sign change of chirality of molecular helical structures with the complication of their hierarchical level of organization.

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Katsuno, Nakako, Misa Onishi, Takumi Taguchi, Chie Ohmoto, Hideyuki Yamaguchi, Takuya Hashimoto, Satoshi Iwamoto, Teppei Imaizumi und Takahisa Nishizu. „Cross-hierarchical analysis of self-assembly dynamics in enzyme-treated rice gel during retrogradation“. Food Hydrocolloids 156 (November 2024): 110355. http://dx.doi.org/10.1016/j.foodhyd.2024.110355.

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Buehler, Markus J. „Mesoscale modeling of mechanics of carbon nanotubes: Self-assembly, self-folding, and fracture“. Journal of Materials Research 21, Nr. 11 (November 2006): 2855–69. http://dx.doi.org/10.1557/jmr.2006.0347.

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Using concepts of hierarchical multiscale modeling, we report development of a mesoscopic model for single-wall carbon nanotubes with parameters completely derived from full atomistic simulations. The parameters in the mesoscopic model are fit to reproduce elastic, fracture, and adhesion properties of carbon nanotubes, in this article demonstrated for (5,5) carbon nanotubes. The mesoscale model enables modeling of the dynamics of systems with hundreds of ultralong carbon nanotubes over time scales approaching microseconds. We apply our mesoscopic model to study self-assembly processes, including self-folding, bundle formation, as well as the response of bundles of carbon nanotubes to severe mechanical stimulation under compression, bending, and tension. Our results with mesoscale modeling corroborate earlier results, suggesting a novel self-folding mechanism, leading to creation of racket-shaped carbon nanotube structures, provided that the aspect ratio of the carbon nanotube is sufficiently large. We find that the persistence length of the (5,5) carbon nanotube is on the order of a few micrometers in the temperature regime from 300 to 1000 K.

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Bystrov, Vladimir, Ilya Likhachev, Alla Sidorova, Sergey Filippov, Aleksey Lutsenko, Denis Shpigun und Ekaterina Belova. „Molecular Dynamics Simulation Study of the Self-Assembly of Phenylalanine Peptide Nanotubes“. Nanomaterials 12, Nr. 5 (03.03.2022): 861. http://dx.doi.org/10.3390/nano12050861.

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In this paper, we propose and use a new approach for a relatively simple technique for conducting MD simulation (MDS) of various molecular nanostructures, determining the trajectory of the MD run and forming the final structure using external force actions. A molecular dynamics manipulator (MD manipulator) is a controlled MDS type. As an example, the applicability of the developed algorithm for assembling peptide nanotubes (PNT) from linear phenylalanine (F or Phe) chains of different chirality is presented. The most adequate regimes for the formation of nanotubes of right chirality D from the initial L-F and nanotubes of left chirality L of their initial dipeptides D-F modes were determined. We use the method of a mixed (vector–scalar) product of the vectors of the sequence of dipole moments of phenylalanine molecules located along the nanotube helix to calculate the magnitude and sign of chirality of self-assembled helical phenylalanine nanotubes, which shows the validity of the proposed approach. As result, all data obtained correspond to the regularity of the chirality sign change of the molecular structures with a hierarchical complication of their organization.

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Depta, Philipp Nicolas, Maksym Dosta, Wolfgang Wenzel, Mariana Kozlowska und Stefan Heinrich. „Hierarchical Coarse-Grained Strategy for Macromolecular Self-Assembly: Application to Hepatitis B Virus-Like Particles“. International Journal of Molecular Sciences 23, Nr. 23 (24.11.2022): 14699. http://dx.doi.org/10.3390/ijms232314699.

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Macromolecular self-assembly is at the basis of many phenomena in material and life sciences that find diverse applications in technology. One example is the formation of virus-like particles (VLPs) that act as stable empty capsids used for drug delivery or vaccine fabrication. Similarly to the capsid of a virus, VLPs are protein assemblies, but their structural formation, stability, and properties are not fully understood, especially as a function of the protein modifications. In this work, we present a data-driven modeling approach for capturing macromolecular self-assembly on scales beyond traditional molecular dynamics (MD), while preserving the chemical specificity. Each macromolecule is abstracted as an anisotropic object and high-dimensional models are formulated to describe interactions between molecules and with the solvent. For this, data-driven protein–protein interaction potentials are derived using a Kriging-based strategy, built on high-throughput MD simulations. Semi-automatic supervised learning is employed in a high performance computing environment and the resulting specialized force-fields enable a significant speed-up to the micrometer and millisecond scale, while maintaining high intermolecular detail. The reported generic framework is applied for the first time to capture the formation of hepatitis B VLPs from the smallest building unit, i.e., the dimer of the core protein HBcAg. Assembly pathways and kinetics are analyzed and compared to the available experimental observations. We demonstrate that VLP self-assembly phenomena and dependencies are now possible to be simulated. The method developed can be used for the parameterization of other macromolecules, enabling a molecular understanding of processes impossible to be attained with other theoretical models.

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Gitsas, A., G. Floudas, M. Mondeshki, I. Lieberwirth, H. W. Spiess, H. Iatrou, N. Hadjichristidis und A. Hirao. „Hierarchical Self-Assembly and Dynamics of a Miktoarm StarchimeraComposed of Poly(γ-benzyl-l-glutamate), Polystyrene, and Polyisoprene“. Macromolecules 43, Nr. 4 (23.02.2010): 1874–81. http://dx.doi.org/10.1021/ma902631e.

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Nguyen, Trung Dac, Benjamin A. Schultz, Nicholas A. Kotov und Sharon C. Glotzer. „Generic, phenomenological, on-the-fly renormalized repulsion model for self-limited organization of terminal supraparticle assemblies“. Proceedings of the National Academy of Sciences 112, Nr. 25 (10.06.2015): E3161—E3168. http://dx.doi.org/10.1073/pnas.1509239112.

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Self-limited, or terminal, supraparticles have long received great interest because of their abundance in biological systems (DNA bundles and virus capsids) and their potential use in a host of applications ranging from photonics and catalysis to encapsulation for drug delivery. Moreover, soft, uniform colloidal aggregates are a promising candidate for quasicrystal and other hierarchical assemblies. In this work, we present a generic coarse-grained model that captures the formation of self-limited assemblies observed in various soft-matter systems including nanoparticles, colloids, and polyelectrolytes. Using molecular dynamics simulations, we demonstrate that the assembly process is self-limited when the repulsion between the particles is renormalized to balance their attraction during aggregation. The uniform finite-sized aggregates are further shown to be thermodynamically stable and tunable with a single dimensionless parameter. We find large aggregates self-organize internally into a core–shell morphology and exhibit anomalous uniformity when the constituent nanoparticles have a polydisperse size distribution.

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Singh, Nidhi, und Wenjin Li. „Recent Advances in Coarse-Grained Models for Biomolecules and Their Applications“. International Journal of Molecular Sciences 20, Nr. 15 (01.08.2019): 3774. http://dx.doi.org/10.3390/ijms20153774.

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Molecular dynamics simulations have emerged as a powerful tool to study biological systems at varied length and timescales. The conventional all-atom molecular dynamics simulations are being used by the wider scientific community in routine to capture the conformational dynamics and local motions. In addition, recent developments in coarse-grained models have opened the way to study the macromolecular complexes for time scales up to milliseconds. In this review, we have discussed the principle, applicability and recent development in coarse-grained models for biological systems. The potential of coarse-grained simulation has been reviewed through state-of-the-art examples of protein folding and structure prediction, self-assembly of complexes, membrane systems and carbohydrates fiber models. The multiscale simulation approaches have also been discussed in the context of their emerging role in unravelling hierarchical level information of biosystems. We conclude this review with the future scope of coarse-grained simulations as a constantly evolving tool to capture the dynamics of biosystems.

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G.P., Darshan, Premkumar H.B., Nagabhushana H., Sharma S.C., Umesh B. und Basavaraj R.B. „Nucleation and self-assembly dynamics of hierarchical YAlO3:Ce3+ architectures: Nano probe for in vitro dermatoglyphics and anti-mimetic applications“. Materials Science and Engineering: C 99 (Juni 2019): 282–95. http://dx.doi.org/10.1016/j.msec.2019.01.060.

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Singer, W. „Consciousness and the structure of neuronal representations“. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 353, Nr. 1377 (29.11.1998): 1829–40. http://dx.doi.org/10.1098/rstb.1998.0335.

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The hypothesis is defended that brains expressing phenomenal awareness are capable of generating metarepresentations of their cognitive processes, these metarepresentations resulting from an iteration of self–similar cortical operations. Search for the neuronal substrate of awareness therefore converges with the search for the nature of neuronal representations. It is proposed that evolved brains use two complementary representational strategies. One consists of the generation of neurons responding selectively to a particular constellation of features and is based on selective recombination of inputs in hierarchically structured feedforward architectures. The other relies on the dynamic association of feature–specific cells into functionally coherent cell assemblies that, as a whole, represent the constellation of features defining a particular perceptual object. Arguments are presented that favour the notion that the metarepresentations supporting awareness are established in accordance with the second strategy. Experimental data are reviewed that are compatible with the hypothesis that evolved brains use assembly codes for the representation of contents and that these assemblies become organized through transient synchronization of the discharges of associated neurons. It is argued that central states favouring the formation of assembly–based representations are similar to those favouring awareness.

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Lewis, Sean C., Stephen L. W. McMillan, Mordecai-Mark Mac Low, Claude Cournoyer-Cloutier, Brooke Polak, Martijn J. C. Wilhelm, Aaron Tran et al. „Early-forming Massive Stars Suppress Star Formation and Hierarchical Cluster Assembly“. Astrophysical Journal 944, Nr. 2 (01.02.2023): 211. http://dx.doi.org/10.3847/1538-4357/acb0c5.

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Abstract Feedback from massive stars plays an important role in the formation of star clusters. Whether a very massive star is born early or late in the cluster formation timeline has profound implications for the star cluster formation and assembly processes. We carry out a controlled experiment to characterize the effects of early-forming massive stars on star cluster formation. We use the star formation software suite Torch, combining self-gravitating magnetohydrodynamics, ray-tracing radiative transfer, N-body dynamics, and stellar feedback, to model four initially identical 104 M ⊙ giant molecular clouds with a Gaussian density profile peaking at 521.5 cm−3. Using the Torch software suite through the AMUSE framework, we modify three of the models, to ensure that the first star that forms is very massive (50, 70, and 100 M ⊙). Early-forming massive stars disrupt the natal gas structure, resulting in fast evacuation of the gas from the star-forming region. The star formation rate is suppressed, reducing the total mass of the stars formed. Our fiducial control model, without an early massive star, has a larger star formation rate and total efficiency by up to a factor of 3, and a higher average star formation efficiency per freefall time by up to a factor of 7. Early-forming massive stars promote the buildup of spatially separate and gravitationally unbound subclusters, while the control model forms a single massive cluster.

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Doudin, Nassar, Greg Collinge, Pradeep Kumar Gurunathan, Mal-Soon Lee, Vassiliki-Alexandra Glezakou, Roger Rousseau und Zdenek Dohnálek. „Creating self-assembled arrays of mono-oxo (MoO3)1 species on TiO2(101) via deposition and decomposition of (MoO3)n oligomers“. Proceedings of the National Academy of Sciences 118, Nr. 4 (20.01.2021): e2017703118. http://dx.doi.org/10.1073/pnas.2017703118.

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Hierarchically ordered oxides are of critical importance in material science and catalysis. Unfortunately, the design and synthesis of such systems remains a key challenge to realizing their potential. In this study, we demonstrate how the deposition of small oligomeric (MoO3)1–6 clusters—formed by the facile sublimation of MoO3 powders—leads to the self-assembly of locally ordered arrays of immobilized mono-oxo (MoO3)1 species on anatase TiO2(101). Using both high-resolution imaging and theoretical calculations, we reveal the dynamic behavior of the oligomers as they spontaneously decompose at room temperature, with the TiO2 surface acting as a template for the growth of this hierarchically structured oxide. Transient mobility of the oligomers on both bare and (MoO3)1-covered TiO2(101) areas is identified as key to the formation of a complete (MoO3)1 overlayer with a saturation coverage of one (MoO3)1 per two undercoordinated surface Ti sites. Simulations reveal a dynamic coupling of the reaction steps to the TiO2 lattice fluctuations, the absence of which kinetically prevents decomposition. Further experimental and theoretical characterizations demonstrate that (MoO3)1 within this material are thermally stable up to 500 K and remain chemically identical with a single empty gap state produced within the TiO2 band structure. Finally, we see that the constituent (MoO3)1 of this material show no proclivity for step and defect sites, suggesting they can reliably be grown on the (101) facet of TiO2 nanoparticles without compromising their chemistry.

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Miyao, Toshihiro, Hanako Nishino, Hiroko Yamazaki, Satoko Sato, Kayoko Tamoto, Makoto Uchida, Akihiro Iiyama et al. „The Formation Mechanism of Ordered Mesoporous Carbon with Network-Structure: A Novel Support Material for Pt-Based Catalysts in PEFC Cathodes“. ECS Meeting Abstracts MA2023-02, Nr. 40 (22.12.2023): 1998. http://dx.doi.org/10.1149/ma2023-02401998mtgabs.

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INTRODUCTION To achieve carbon neutrality in the upcoming sustainable society, it is crucial to utilize hydrogen as a fuel in the transportation sector. Fuel cell vehicles are expected to play an important role in the future hydrogen society, but there are still challenges to be overcome before their widespread adoption. For example, Pt/C-based catalysts used in PEFC cathodes have an issue with poisoning of the Pt due to direct contact with the ionomer, especially during low-load operation. Recently, a new approach using accessible-pore carbons has been proposed, where Pt is placed at an appropriate position within the nanopores of a carbon support to suppress ionomer poisoning of Pt [1]. In order to realize this concept, it is essential to design a mesoporous carbon support that possesses nanopores with appropriate size and proper ordering. We have developed an ordered mesoporous carbon with a hierarchical network structure (Net-OMC) consisting of small OMC particles of several tens of nm in size, which are connected to form a network structure with well-developed primary pores. The Net-OMC exhibited highly ordered nanopores on the surface of the OMC primary particles, with a pore size ca. 5 nm and an interpore distance of ca. 8 nm. Pt nanoparticles were loaded selectively within the Net-OMC nanopores by the selective Pt-deposition technique developed by our research group. Pt/Net-OMC catalyst exhibited higher mass activity and durability for the ORR in comparison with those for a commercial Pt/CB catalyst [2]. In this study, the formation mechanism of Net-OMC and the relationship between the catalytic properties of Pt/Net-OMC and its pore structure was investigated in detail. EXPERIMENTAL Net-OMC powder was synthesized with resol-nonionic surfactant micelles as a carbon source and structure-directing agent. Resol-F127 (nonionic surfactant) micelles were synthesized by mixing phenol, formaldehyde, water and F127 with sodium hydroxide. After hydrothermal treatment of the mixture, the resulting solid was filtered and washed thoroughly and dried under vacuum. The obtained powder was carbonized at 700 ºC followed by annealing at 1000 ºC. Pt was deposited on the Net-OMC powder by selective deposition techniques. Cyclic voltammetry and linear sweep voltammetry were carried out in N2-saturated and O2-saturated 0.1 M HClO4 solution at 25 ºC using the conventional rotating disk electrode (RDE) technique. Potential step cycling measurements simulating load cycling between 0.6 V and 1.0 V vs. RHE were carried out according to the FCCJ protocol. Coating of the catalyst on a glassy carbon disk substrate was carried out by an electrospray (ES) coating technique developed by our group [3]. N2 adsorption measurements at liquid nitrogen temperature were carried out. The morphology of the Pt/ns-OMC was observed by scanning transmission electron microscopy (STEM). RESULTS AND DISCUSSION STEM images for the ordered mesoporous carbon particles with network structure (Net-OMC) with varying concentration during hydrothermal synthesis are shown in Figure 1. In Fig. 1(a), the network structure formed by connection of OMC primary nanoparticles with developed macropores is clearly observed. The OMC nanoparticles were tightly connected via a thick necking structure. From the high magnification image (Fig. 1(a), inset), highly ordered nanopores were observed on the surface of the OMC particles. The OMC primary particle size and the connecting neck diameter changed with the resol micelle concentration during the hydrothermal treatment. When the concentration of the micelle solution was decreased, both the primary particle size and necking length decreased. At a concentration of 1.8 mmol l-1, the formation of monodisperse particles with roughly the same size from the resol-F127 micelle particles was observed, as estimated by dynamic light scattering analysis. Thus, it is believed that the Net-OMC structure is formed through the self-assembly of micelle particles during the hydrothermal synthesis. The controllable network structure of Net-OMC is expected to provide a favorable porous structure of the catalyst layer for the MEA measurement even during high-load operation. References: [1] V. Yarlagadda, M. Carpenter, T. Moylan, R Kukreja, R. Koestner, W. Gu, L. Thompson, A. Kongkanand, ACS Energy Lett., 3, 618 (2018). [2] T. Miyao, H. Nishino, H. Yamazaki, S. Sato, K. Tamoto, M. Uchida, A. Iiyama, K. Shibanuma and N. Koizumi, 242nd ECS Abstract, #I01D-1578(2022). [3] S. Cho, K. Tamoto and M. Uchida, Energy Fuels, 34, 14853 (2020). Acknowledgement: This work was partially supported by the ECCEED’30-FC project from NEDO. Figure 1

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IVANCEVIC, VLADIMIR, und SANJEEV SHARMA. „COMPLEXITY IN HUMAN AND HUMANOID BIOMECHANICS“. International Journal of Humanoid Robotics 05, Nr. 04 (Dezember 2008): 679–98. http://dx.doi.org/10.1142/s0219843608001571.

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We propose the following complexity conjecture: in a combined biomechanical system, where the action of Newtonian laws cannot be neglected, it is the mechanical part that determines the lower limit of complexity of the combined system, commonly defined as the number of mechanical degrees of freedom. The biological part of such a system, being "more intelligent", naturally serves as a "controller" for the "nonintelligent" mechanical "plant". Although, in some special cases, the behavior of the combined system might have a "simple" output, a realistic internal state space analysis shows that the total system complexity represents either the superposition, or a kind of "macroscopic entanglement" of the two partial complexities. Neither "mutual canceling" nor "averaging" of the mechanical degrees of freedom generally occurs in such a biomechanical system. The combined system has both dynamical and control complexities. The "realistic" computational model of such a system also has its own computational complexity. We demonstrate the validity of the above conjecture using the example of the physiologically realistic computer model. We further argue that human motion is the simplest well-defined example of a general human behavior, and discuss issues of simplicity versus predictability/controllability in complex systems. Further, we discuss self-assembly in relation to conditioned training in human/humanoid motion. It is argued that there is a significant difference in the observational resolution of human motion while one is watching "subtle" movements of a human hands playing a piano versus "coarse" movements of a human crowd at a football stadium from an orbital satellite. Techniques such as cellular automata can model the coarse crowd motion, but not the subtle hierarchical neural control of the dynamics of human hands playing a piano. Therefore, we propose the observational resolution as a new measure of biomechanical complexity. Finally, there is a possible route to apparent simplicity in biomechanics, in the form of oscillatory synchronization, both external (kinematical) and internal (control).

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Gong, Xue, Ruomeng Li, Jiajia Zhang, Pu Zhang, Zhongwei Jiang, Lianzhe Hu, Xiaoqing Liu, Yi Wang und Fuan Wang. „Scaling up of a Self‐Confined Catalytic Hybridization Circuit for Robust microRNA Imaging“. Advanced Science, 13.04.2024. http://dx.doi.org/10.1002/advs.202400517.

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AbstractThe precise regulation of cellular behaviors within a confined, crowded intracellular environment is highly amenable in diagnostics and therapeutics. While synthetic circuitry system through a concatenated chemical reaction network has rarely been reported to mimic dynamic self‐assembly system. Herein, a catalytic self‐defined circuit (CSC) for the hierarchically concatenated assembly of DNA domino nanostructures is engineered. By incorporating pre‐sealed symmetrical fragments into the preying hairpin reactants, the CSC system allows the hierarchical DNA self‐assembly via a microRNA (miRNA)‐powered self‐sorting catalytic hybridization reaction. With minimal strand complexity, this self‐sustainable CSC system streamlined the circuit component and achieved localization‐intensified cascaded signal amplification. Profiting from the self‐adaptively concatenated hybridization reaction, a reliable and robust method has been achieved for discriminating carcinoma tissues from the corresponding para‐carcinoma tissues. The CSC‐sustained self‐assembly strategy provides a comprehensive and smart toolbox for organizing various hierarchical DNA nanostructures, which may facilitate more insights for clinical diagnosis and therapeutic assessment.

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Warner, Christopher M., Olexandr Isayev, Aimee R. Poda, Michael F. Cuddy, Wayne D. Hodo, Seung-Wuk Lee und Edward J. Perkins. „Computational modeling of bacteriophage self-assembly during formation of hierarchical structures“. MRS Proceedings 1722 (2015). http://dx.doi.org/10.1557/opl.2015.428.

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ABSTRACTDesigning new materials with well-defined structures and desired functions is a challenge in materials science, especially with nanomaterials. Nature, however, solves design of these materials through a self-assembling, hierarchically ordered process. We have investigated the mechanisms by which the high- aspect ratio and unique surface chemistry of M13 bacteriophage can give rise to increasingly complex, hierarchically ordered, bundled phage structures with a wide range of material applications. A molecular dynamic simulation of the 3-D structure of a 20-nm section of wild type (WT) and mutant phage types were developed based on WT phage crystal structure and ab initio calculations. Simulations of these phage were then used to examine repulsive and attractive forces of the particles in solution. Examination of contact interactions between two WT phage indicated the phage were maximally attracted to each other in a head to tail orientation. A mutant phage (4E) with a higher negative surface charge relative to WT phage also preferentially ordered head to tail in solution. In contrast, a mutant phage (CLP8) with a net positive surface charge had minimal repulsion in a 90° orientation. Understanding the self-assembly process through molecular dynamic simulations and decomposition of fundamental forces driving inter- and intra-strand interactions has provided a qualitative assessment of mechanisms that lead to hierarchical phage bundle structures. Results from simulation agree with experimentally observed patterns from self-assembly. We anticipate using this system to further investigate development of hierarchical structures not only from biological molecules but also from synthetic materials.

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