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Design Growth of Nanophosphors and Their Applications
Published in Ru-Shi Liu, Xiao-Jun Wang, Phosphor Handbook, 2022
Ming-Hsien Chan, Wen-Tse Huang, Michael Hsiao, Ru-Shi Liu
When the protein is folded, some pores are formed inside, and nanoparticles or structures can be made with this characteristic [23–25]. Take a protein that exists on the surface of bacteria (S-layer) as an example. S-layer protein has many biological functions, such as forming protective coats, providing bacteria attachment and identification, and maintaining cell shape [26–28]. Because S-layer protein has the same characteristics, it can be combined with many substances, including some materials like “Silicon Wafer Metal and Polymer”, and biological substances like antibodies. If S-layer protein is separated, it can be found that it can self-assemble into different types under various interfaces, such as lipid film or liposome, and these structures are the templates we need, and these templates can be used to create nanostructures (Figure 10.3). The following takes the preparation of Pt clusters as an example. First, the S-layer sheet on the suspension-ureae cell is separated, and then the Pt in K2PtC4 is reduced and settled on the S-layer by the molecular deposition method to form Pt clusters [29]. Similar reactions can also be used to prepare Ag, CdS nanoparticles.
Engineering Living Materials: Designing Biological Cells as Nanomaterials Factories
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Peter Q. Nguyen, Pichet Praveschotinunt, Avinash Manjula-Basavanna, Ilia Gelfat, Neel S. Joshi
Researchers focus on manipulating proteins as structural and functional components of ELMs for multiple reasons. Protein engineering offers precise control of peptide sequences based on genetic codes introduced into the organisms, enabling intricate features, such as programmed self-assembly, specific binding to different materials, and the display of modular functional proteinaceous domains. Early efforts of engineering programmable ELM-based scaffolds from bacteria involve bacterial cell surface display, which enables bacterial cells to interact with specified targets (Daugherty 2007). Along a similar trajectory, scientists have also engineered S-layer proteins, which are parts of cell envelopes found in archaea and many bacteria and play roles in self-defense, adhesion, and barrier functions by adopting two-dimensional crystalline patterns (Figure 8.1f). S-layer proteins can be fused to heterologous, functional domains such as enzymes, ligands, antibodies, or antigens to create novel nanobiomaterials beneficial for creating biocompatible surfaces, mucosal vaccines, bioremediation and biomineralization platforms, affinity matrices, and microcarriers (Ilk, Egelseer, and Sleytr 2011; Schuster and Sleytr 2014).
Microbial Biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
In many bacteria, an S-layer of rigidly arrayed protein molecules covers the outside of the cell. This layer provides chemical and physical protection for the cell surface and can act as a macromolecular diffusion barrier. S-layers have diverse but mostly poorly understood functions, although they are known to act as virulence factors in Campylobacter and contain surface enzymes in Bacillus stearothermophilus. Flagella are rigid protein structures, approximately 20 nm in diameter and up to 20 μm in length, that are used for motility. Flagella are driven by the energy released by the transfer of ions down an electrochemical gradient across the cell membrane. Fimbriae are fine filaments of protein, just 2–10 nm in diameter and up to several micrometers in length. They are distributed over the surface of the cell and resemble fine hairs when seen under the electron microscope. Fimbriae are believed to be involved in attachment to solid surfaces or to other cells and are essential for the virulence of some bacterial pathogens. Pili (pilus in the singular) are cellular appendages slightly larger than fimbriae, which can transfer genetic material between bacterial cells in a process called conjugation.
Formation of planar hybrid lipid/polymer membranes anchored to an S-layer protein lattice by vesicle binding and rupture
Published in Soft Materials, 2020
Christian Czernohlavek, Bernhard Schuster
There are significant efforts to design synthetic membranes as mimics of biomembranes.[1] The building blocks of bio-inspired systems constitute unique, predictable and tunable properties, diversity, and the possibility to fabricate ultrathin two-dimensional structures in the square-micrometer range with an astonishing variety of functionalities at the nanoscale.[2–7] Moreover, these natural building blocks like, e.g., lipids, proteins, and polymers self-assemble spontaneously into supramolecular structures.[8–10] One of the most important template for bio-inspired architectures is the cell envelope structure of prokaryotes, which is a complex layered structure comprising of a cell membrane and in many cases of a monomolecular array of protein subunits forming the outermost surface layer (S-layer).[4,9,11,12] The importance of cell membranes in biological systems as a barrier, preserver of the physical integrity of the cell and host for integral membrane proteins has prompted the development of membrane platforms that recapitulate fundamental aspects of membrane biology, especially the lipid bilayer environment.[7,13,14] This environment is of utmost importance for integral membrane proteins like channels, proton pumps, and (G protein-coupled) receptors, which are responsible for carrying out important specific membrane functions.[15–19]
Current research and perspectives on microalgae-derived biodiesel
Published in Biofuels, 2020
Kartik Singh, Deeksha Kaloni, Sakshi Gaur, Shipra Kushwaha, Garima Mathur
To assist harvesting and avoid expensive biomass recovery processes currently required in algal biofuel systems, a fatty acid secretion strategy was employed in cyanobacterium Synechocysti spp. PCC 6803 species. Fatty acid secretion yields were amplified by weakening the S layer and peptidoglycan wall of the cell. In addition, acyl-acyl carrier protein thioesterase (TE) from the California bay plant Umbellularia californica were heterogeneously expressed in the given species of cyanobacterium. The resultant mutant Synechocysti spp. PCC 6803 strains were able to overproduce fatty acids (C10–C18) and secrete them into the medium, which could then be easily retrieved off the surface of the culture. Hence, fatty acid-secreting cyanobacteria are a promising technology for renewable biodiesel production [154].
Electronic structure, optical properties, and phonon transport in Janus monolayer PtSSe via first-principles study
Published in Philosophical Magazine, 2019
Wang-Li Tao, Yi Mu, Cui-E Hu, Yan Cheng, Guang-Fu Ji
Following the discovery of graphene [1–3], low dimensional materials have attracted increasing attention due to their many extraordinary physical properties originating from the bulk to monolayer transition in condensed matter physics and material science fields. Soon afterwards, among the wider family of two-dimensional materials, a series of interesting findings in transitional metal dichalcogenide (TMD) [4], group-V [5,6], group IV-VI and group-IV monolayers [7] underpin the great potential applications in electronic, thermoelectric, quantum and optoelectronic devices. As is well-known, the electronic structure of two-dimensional materials is affected by structural symmetry-breaking. Compared with graphene and other two-dimensional materials, TMDs have an in-plane asymmetry, which gives them extraordinary electro-optical properties with great applications in the field of optoelectronics [8,9]. Lu et al. [10] successfully synthesised Janus monolayer MoSSe by fully replacing the top S layer with Se, leading to an out-of-plane structural asymmetry. They confirmed the existence of vertical dipoles from second harmonic generation and piezoresponse force microscopy measurements. The large Rashba spin splitting and strong piezoelectric effects were previously predicted in polar and multilayer Janus TMDs of the form MXY (M = Mo and W, and X/Y = S, Se and Te) based on first-principles, which may provide special contributions to energy harvesters, sensors, semiconductor spintronics, and valleytronics [11,12]. In addition, the mechanical and electronic properties of MXY (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W; X/Y = S, Se, Te) TMDs have also been investigated using density functional theory (DFT), showing that breaking the out-of-plane structural symmetry can be used to tune their electronic and mechanical behaviours [13].