Crystal tectonics: Novel routes to the ordered aggregation and self assembly of inorganic solids

Author(s):  
Brigid R. Heywood

Oriented materials attract considerable attention since thay have the potential to exhibit collective properties which exceed those of the isotropic species by several orders of magnitude. Much success has already been achieved with organic materials, e.g. liquid crystals, conducting polymers, but reliable protocols for the construction of organised crystal micro-architectures from inorganic solids have yet to be established. Given the potential advantages of translating molecular properties (optical, piezoelectric, catalytic) to the macroscopic scale strategies for the construction of hierarchical crystal assemblies, crystal tectonics, merit particular consideration.This crystal tectonics route to the synthesis of anisotropic inorganic materials remains entirely untested, but draws much of its inspiration from the study of deterministic self-organisation in biological systems. Such self-organisation relies on a series of highly specific “host-guest”, ligandreceptor type interactions (more typically cited examples of such include, enzyme-substrate-cofactor binding, antibody-antigen complexation, and triplet/base matching during polypeptide synthesis). The biogenic formation of hierarchical inorganic arrays, biomineralization, is remarkable not only for its control of crystallisation to yield solids of uniform size and unusual habit, but equally for the construction of elaborate functional micro-architectures from these biosolids.

Author(s):  
Brigid R. Hey wood ◽  
Caroline German

Anisotropic inorganic materials are desirable as they possess unique physical and chemical properties resulting from the manner in which the particulate components assemble. The facility to control the ordering of colloidal inorganic particles could presage dramatic improvements in the fabrication of ceramics, catalysts or paints. Biological systems have already harnessed the manifold advantages of such materials, consider shells, teeth, bones etc.(Figures 1 & 2). Synthetic strategies for the formation of nanodimensional inorganic solids abound but there are few reliable methods currently available for directing their subsequent aggregation. Some degree of ordering can be achieved by the application of external forces (magnetic, electrical) but the aggregates readily dissemble once the stimulus is removed. The requirement is, therefore, for an effective molecular route to the ordered assembly and construction of hierarchical inorganic microstructures.The present work forms part of an extended programme of research investigating crystal tectonics, the ordering of nanodimensional inorganic solids. Here, the controlled morphological tailoring of inorganic crystals to yield a form which favours self-assembly has been investigated.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 584
Author(s):  
Shalendra Kumar ◽  
Faheem Ahmed ◽  
Nagih M. Shaalan ◽  
Osama Saber

Bio-inspired synthesis is a novel and attractive environmentally friendly route to generating inorganic materials. In this work, the preparation of CeO2 NPs using egg white and investigation of their antibacterial properties both in liquid and solid growth medium against Escherichia coli and Staphylococcus aureus bacteria were reported. The CeO2 nanoparticles were characterized using X-ray diffraction (XRD), Field emission transmission electron microscope (FETEM), UV-Vis, Raman, and antibacterial measurements. The results from XRD and TEM analysis showed that the prepared nanoparticles were a single phase in the nano regime (5–7 nm) with spherical shape and uniform size distribution. Optical properties reflected the characteristics peaks of CeO2 in the UV-Vis range with a bandgap ~2.80 eV. The antibacterial activity of the synthesized NPs was achieved under ambient conditions with different bacteria and the results showed that the properties were different for both the bacteria. The highest activity with an inhibition zone of about 22 mm against S. aureus was obtained as compared with the 19 mm zone of inhibition obtained with E.coli. This finding will be of major significance that indicates a possibility to develop CeO2 NPs as antibacterial agents against extensive microorganisms to control and prevent the spread and persistence of bacterial infections.


2012 ◽  
Vol 30 (1) ◽  
pp. 269-279 ◽  
Author(s):  
Kai Shi ◽  
Fude Cui ◽  
Hongshu Bi ◽  
Yanbo Jiang ◽  
Hang Shi ◽  
...  

2020 ◽  
Author(s):  
Szabolcs Horvát ◽  
Adeeba Fathima ◽  
Stefan Görlich ◽  
Carl Modes ◽  
Michael Schlierf ◽  
...  

Abstract Morphogenesis of the silica based cell walls of diatoms, a large group of microalgae, is a paradigm for the self-assembly of complex 3D nano- and microscale patterned inorganic materials. In recent years, loss-of-function studies using genetic manipulation were successfully applied for the identification of genes that guide silica morphogenesis in diatoms. These studies revealed that the loss of one gene can affect multiple morphological parameters, and the morphological changes can be rather subtle being blurred by natural variations in morphology even within the same clone. Both factors severely hamper the identification of morphological mutants using subjective by-eye inspection of electron micrographs. Here we have developed automated image analysis for objectively quantifying the morphology of ridge networks and pore densities from numerous electron micrographs of diatom biosilica. This study demonstrated differences in ridge network morphology and pore density in diatoms growing on ammonium rather than nitrate as sole nitrogen source. Furthermore, it revealed shortcomings in previous by-eye evaluation of the biosilica phenotype of the silicanin-1 knockout mutant. We anticipate that the computational methods established in the present work, will be invaluable for unraveling genotype-phenotype correlations in diatom biosilica morphogenesis.


Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3905 ◽  
Author(s):  
Jong-Min Lim ◽  
Sehee Jeong

Spherical PS/HEMA opal structure and spherical titania inverse opal structure were fabricated by self-assembly of colloidal nanoparticles in uniform aerosol droplets generated with electro-hydrodynamic atomization method. When a solution of PS/HEMA nanoparticles with uniform size distribution was used, PS/HEMA nanoparticles self-assembled into a face-centered cubic (FCC) structure by capillary force with the evaporation of the solvent in aerosol droplet, resulting in a spherical opal structure. When PS/HEMA nanoparticles and anatase titania nanoparticles were dispersed simultaneously into the solution, titania nanoparticles with relatively smaller size were assembled at the interstitial site of PS/HEMA nanoparticles packed in the FCC structure, resulting in a spherical opal composite structure. Spherical titania inverse opal structure was fabricated after removing PS/HEMA nanoparticles from the spherical opal composite structure by calcination.


Author(s):  
Curtis Taylor ◽  
Eric Stach ◽  
Gregory Salamo ◽  
Ajay Malshe

The ability to pattern quantum dots with high spatial positioning and uniform size is critical for the realization of future electronic devices with novel properties and performance that surpass present technology. This work discusses the exploration of an innovative nanopatterning technique to direct the self-assembly of nanostructures. The technique focuses on perturbing surface strain energy by nanoindentation in order to mechanically bias quantum dot nucleation. Growth of InAs quantum dots on nanoindent templates is performed using molecular beam epitaxy (MBE). The effect of indent spacing and size on the patterned growth is investigated. The structural analysis of the quantum dots including spatial ordering, size, and shape are characterized by ex-situ atomic force microscopy (AFM). Results reveal that the indent patterns clearly bias nucleation with dot structures selectively growing on top of each indent. It is speculated that the biased nucleation is due to a combination of favorable surface strain attributed to subsurface dislocation strain fields and/or multi-atomic step formation at the indent sites, which leads to increased adatom diffusion on the patterned area.


2016 ◽  
Vol 7 ◽  
pp. 613-629 ◽  
Author(s):  
Claudia Koch ◽  
Fabian J Eber ◽  
Carlos Azucena ◽  
Alexander Förste ◽  
Stefan Walheim ◽  
...  

The rod-shaped nanoparticles of the widespread plant pathogentobacco mosaic virus(TMV) have been a matter of intense debates and cutting-edge research for more than a hundred years. During the late 19th century, their behavior in filtration tests applied to the agent causing the 'plant mosaic disease' eventually led to the discrimination of viruses from bacteria. Thereafter, they promoted the development of biophysical cornerstone techniques such as electron microscopy and ultracentrifugation. Since the 1950s, the robust, helically arranged nucleoprotein complexes consisting of a single RNA and more than 2100 identical coat protein subunits have enabled molecular studies which have pioneered the understanding of viral replication and self-assembly, and elucidated major aspects of virus–host interplay, which can lead to agronomically relevant diseases. However, during the last decades, TMV has acquired a new reputation as a well-defined high-yield nanotemplate with multivalent protein surfaces, allowing for an ordered high-density presentation of multiple active molecules or synthetic compounds. Amino acid side chains exposed on the viral coat may be tailored genetically or biochemically to meet the demands for selective conjugation reactions, or to directly engineer novel functionality on TMV-derived nanosticks. The natural TMV size (length: 300 nm) in combination with functional ligands such as peptides, enzymes, dyes, drugs or inorganic materials is advantageous for applications ranging from biomedical imaging and therapy approaches over surface enlargement of battery electrodes to the immobilization of enzymes. TMV building blocks are also amenable to external control of in vitro assembly and re-organization into technically expedient new shapes or arrays, which bears a unique potential for the development of 'smart' functional 3D structures. Among those, materials designed for enzyme-based biodetection layouts, which are routinely applied, e.g., for monitoring blood sugar concentrations, might profit particularly from the presence of TMV rods: Their surfaces were recently shown to stabilize enzymatic activities upon repeated consecutive uses and over several weeks. This review gives the reader a ride through strikingly diverse achievements obtained with TMV-based particles, compares them to the progress with related viruses, and focuses on latest results revealing special advantages for enzyme-based biosensing formats, which might be of high interest for diagnostics employing 'systems-on-a-chip'.


Author(s):  
Kajal Arora ◽  
Ruchir Rastogi ◽  
Nupur Mehrotra Arora ◽  
Deepak Parashar ◽  
Jeny Paliwal ◽  
...  

AbstractSpike, Envelope and Membrane proteins from the SARS CoV-2 virus surface coat are important vaccine targets. We hereby report recombinant co-expression of the three proteins (Spike, Envelope and Membrane) in a engineered Saccharomyces cerevisiae platform (D-Crypt™) and their self-assembly as Virus-like particle (VLP). This design as a multi-antigenic VLP for SARS CoV-2 has the potential to be a scalable vaccine candidate. The VLP is confirmed by transmission electron microscopy (TEM) images of the SARS CoV-2, along with supportive HPLC, Dynamic Light Scattering (DLS) and allied analytical data. The images clearly outline the presence of a “Corona” like morphology, and uniform size distribution.


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