Three-Dimensional Low Symmetry Mesoporous Silica Structures Templated from Tetra-Headgroup Rigid Bolaform Quaternary Ammonium Surfactant

2005 ◽  
Vol 127 (18) ◽  
pp. 6780-6787 ◽  
Author(s):  
Shaodian Shen ◽  
Alfonso E. Garcia-Bennett ◽  
Zheng Liu ◽  
Qingyi Lu ◽  
Yifeng Shi ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Quaternary Ammonium ◽  
Three Dimensional ◽  
Quaternary Ammonium Surfactant ◽  
Low Symmetry

Synthesis and Aggregation Behavior of a Hexameric Quaternary Ammonium Surfactant

Langmuir ◽  
2011 ◽  
Vol 27 (17) ◽  
pp. 10570-10579 ◽  
Author(s):  
Yaxun Fan ◽  
Yanbo Hou ◽  
Junfeng Xiang ◽  
Defeng Yu ◽  
Chunxian Wu ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Aggregation Behavior ◽  
Quaternary Ammonium Surfactant

scholarly journals The atypical cation-conduction and gating properties of ELIC underscore the marked functional versatility of the pentameric ligand-gated ion-channel fold

2015 ◽  
Vol 146 (1) ◽  
pp. 15-36 ◽  
Author(s):  
Giovanni Gonzalez-Gutierrez ◽  
Claudio Grosman
Keyword(s):  
Quaternary Ammonium ◽  
Time Course ◽  
Three Dimensional ◽  
Mouse Muscle ◽  
Current Decay ◽  
Quaternary Ammonium Cations ◽  
Inward Currents ◽  
Time Courses ◽  
Extracellular Side ◽  
Invariant Functional

The superfamily of pentameric ligand-gated ion channels (pLGICs) is unique among ionotropic receptors in that the same overall structure has evolved to generate multiple members with different combinations of agonist specificities and permeant-ion charge selectivities. However, aside from these differences, pLGICs have been typically regarded as having several invariant functional properties. These include pore blockade by extracellular quaternary-ammonium cations in the micromolar-to-millimolar concentration range (in the case of the cation-selective members), and a gain-of-function phenotype, which manifests as a slower deactivation time course, as a result of mutations that reduce the hydrophobicity of the transmembrane pore lining. Here, we tested this notion on three distantly related cation-selective members of the pLGIC superfamily: the mouse muscle nicotinic acetylcholine receptor (nAChR), and the bacterial GLIC and ELIC channels. Remarkably, we found that, whereas low millimolar concentrations of TMA+ and TEA+ block the nAChR and GLIC, neither of these two quaternary-ammonium cations blocks ELIC at such concentrations; instead, both carry measurable inward currents when present as the only cations on the extracellular side. Also, we found that, whereas lidocaine binding speeds up the current-decay time courses of the nAChR and GLIC in the presence of saturating concentrations of agonists, the binding of lidocaine to ELIC slows this time course down. Furthermore, whereas mutations that reduce the hydrophobicity of the side chains at position 9′ of the M2 α-helices greatly slowed the deactivation time course of the nAChR and GLIC, these mutations had little effect—or even sped up deactivation—when engineered in ELIC. Our data indicate that caution should be exercised when generalizing results obtained with ELIC to the rest of the pLGICs, but more intriguingly, they hint at the possibility that ELIC is a representative of a novel branch of the superfamily with markedly divergent pore properties despite a well-conserved three-dimensional architecture.

scholarly journals High-throughput in-focus differential interference contrast imaging of three-dimensional orientations of single gold nanorods coated with a mesoporous silica shell

RSC Advances ◽  
2020 ◽  
Vol 10 (50) ◽  
pp. 29868-29872
Author(s):  
Geun Wan Kim ◽  
Seokyoung Yoon ◽  
Jung Heon Lee ◽  
Ji Won Ha
Keyword(s):  
Mesoporous Silica ◽  
High Throughput ◽  
Gold Nanorods ◽  
Focal Plane ◽  
Three Dimensional ◽  
Silica Shell ◽  
Differential Interference Contrast ◽  
Contrast Imaging ◽  
3D Space ◽  
Dic Microscopy

Spherical AuNRs@mSiO2 have randomly oriented AuNR cores in 3D space, which could be resolved on the same focal plane by interference-based DIC microscopy.

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