Nanostructured Polymer Duplexes via the Covalent Casting of 1-Dimensional H-Bonding Motifs:  A New Strategy for the Self-Assembly of Macromolecular Precursors

2000 ◽  
Vol 122 (20) ◽  
pp. 5006-5007 ◽  
Author(s):  
Eric A. Archer ◽  
Noah T. Goldberg ◽  
Vincent Lynch ◽  
Michael J. Krische
2018 ◽  
Vol 42 (23) ◽  
pp. 19000-19007 ◽  
Author(s):  
Junqiang Xu ◽  
Qiang Zhang ◽  
Fang Guo ◽  
Yaoqiong Wang ◽  
Jiaqing Xie

We demonstrated a new strategy for the preparation of highly stable mesoporous molecular sieves (TZM) by the desilication of ZSM-5 zeolite and self-assembly of the zeolite subunits in a Na2O·(3.3–3.4) SiO2 aqueous solution.


2019 ◽  
Author(s):  
Huan Cao ◽  
Gary R. Abel ◽  
Qufei Gu ◽  
Gloria-Alexandra V. Gueorguieva ◽  
Yehan Zhang ◽  
...  

<b>Unlike supramolecular self-assembly methods that can organize many unique components into designer shapes in a homogeneous solution (<i>e.g</i>., DNA origami), only relatively simple, symmetric structures consisting of a few unique components have been self-assembled at solid surfaces. As the self-assembly process is confined to the surface/interface by mostly nonspecific attractive interactions, an open question is how these interfacial interactions affect multicomponent self-assembly. To gain a mechanistic understanding of the roles of surface environment in DNA origami self-assembly, here we studied the oligonucleotide-assisted folding of a long single-stranded DNA (ssDNA scaffold) that was end-tethered to a dynamic surface, which could actively regulate the DNA-surface interactions. The results showed that even weak surface attractions can lead to defective structures by inhibiting the merging of multiple domains into complete structures. A combination of surface anchoring and deliberate regulation of DNA-surface interactions allowed us to depart from the existing paradigm of surface confinement via nonspecific interactions and enabled DNA origami folding to proceed in a solution-like environment. Importantly, our new strategy retains the key advantages of surface-mediated self-assembly. Moreover, surface-anchored oligonucleotides could sequence-specifically initiate the growth of DNA origamis of specific sizes and shapes. Our work opens up new opportunities for encoding information into a surface and expressing the information into complex DNA surface architectures for potential nanoelectronics and nanophotonics applications. In addition, our new approach to surface confinement may facilitate the 2D self-assembly of other molecular components, such as proteins, as maintaining conformational freedom may be a general challenge in the self-assembly of complex structures at surfaces.</b><br><br>


2021 ◽  
Author(s):  
Dongming Liu ◽  
Bo Song ◽  
JIa Wang ◽  
Baoxi Li ◽  
Bingnan Wang ◽  
...  

CO<sub>2</sub> utilization has been a hot research topic in academic and industrial respects. Besides converting CO<sub>2</sub> into chemicals and fuels, incorporating it into the polymers to construct functional materials is another promising strategy. However, the CO<sub>2</sub>-involved polymerization techniques should be further developed. In this work, a facile and efficient CO<sub>2</sub>-involved multicomponent polymerization is successfully developed. The reaction of monomers of CO<sub>2</sub>, isocyanides and 2-iodoanilines readily produces soluble and thermally stable <a>poly(</a><a>benzoyleneurea</a>)s with well-defined structures under mild conditions. Thanks to the formed amide groups in the heterocyclic units in the main-chains, the resultant polymers <a>could self-assemble into </a>spheres with sizes between 200 and 1000 nm. <a>The polymers containing tetraphenylethylene (TPE) unit show the unique aggregation-enhanced emission (AEE) features, which could be used to visualize the self-assembly process and morphologies under UV irradiation</a><a>, and serve as fluorescence probe to selectively and sensitively detect Au<sup>3+</sup> ions. </a>Notably, the polymers<i> </i>containing<i> cis</i>- and <i>trans</i>-TPE units exhibit different behaviors in self-assembly and limit of detection for <a>Au<sup>3+</sup> ions</a> due to the different intermolecular interactions. Thus, this work not only provides a new strategy for CO<sub>2</sub> utilization but also furnishes a series of functional heterocyclic polymers for diverse applications.


2021 ◽  
Author(s):  
Dongming Liu ◽  
Bo Song ◽  
JIa Wang ◽  
Baoxi Li ◽  
Bingnan Wang ◽  
...  

CO<sub>2</sub> utilization has been a hot research topic in academic and industrial respects. Besides converting CO<sub>2</sub> into chemicals and fuels, incorporating it into the polymers to construct functional materials is another promising strategy. However, the CO<sub>2</sub>-involved polymerization techniques should be further developed. In this work, a facile and efficient CO<sub>2</sub>-involved multicomponent polymerization is successfully developed. The reaction of monomers of CO<sub>2</sub>, isocyanides and 2-iodoanilines readily produces soluble and thermally stable <a>poly(</a><a>benzoyleneurea</a>)s with well-defined structures under mild conditions. Thanks to the formed amide groups in the heterocyclic units in the main-chains, the resultant polymers <a>could self-assemble into </a>spheres with sizes between 200 and 1000 nm. <a>The polymers containing tetraphenylethylene (TPE) unit show the unique aggregation-enhanced emission (AEE) features, which could be used to visualize the self-assembly process and morphologies under UV irradiation</a><a>, and serve as fluorescence probe to selectively and sensitively detect Au<sup>3+</sup> ions. </a>Notably, the polymers<i> </i>containing<i> cis</i>- and <i>trans</i>-TPE units exhibit different behaviors in self-assembly and limit of detection for <a>Au<sup>3+</sup> ions</a> due to the different intermolecular interactions. Thus, this work not only provides a new strategy for CO<sub>2</sub> utilization but also furnishes a series of functional heterocyclic polymers for diverse applications.


2019 ◽  
Author(s):  
Huan Cao ◽  
Gary R. Abel ◽  
Qufei Gu ◽  
Gloria-Alexandra V. Gueorguieva ◽  
Yehan Zhang ◽  
...  

<b>Unlike supramolecular self-assembly methods that can organize many unique components into designer shapes in a homogeneous solution (<i>e.g</i>., DNA origami), only relatively simple, symmetric structures consisting of a few unique components have been self-assembled at solid surfaces. As the self-assembly process is confined to the surface/interface by mostly nonspecific attractive interactions, an open question is how these interfacial interactions affect multicomponent self-assembly. To gain a mechanistic understanding of the roles of surface environment in DNA origami self-assembly, here we studied the oligonucleotide-assisted folding of a long single-stranded DNA (ssDNA scaffold) that was end-tethered to a dynamic surface, which could actively regulate the DNA-surface interactions. The results showed that even weak surface attractions can lead to defective structures by inhibiting the merging of multiple domains into complete structures. A combination of surface anchoring and deliberate regulation of DNA-surface interactions allowed us to depart from the existing paradigm of surface confinement via nonspecific interactions and enabled DNA origami folding to proceed in a solution-like environment. Importantly, our new strategy retains the key advantages of surface-mediated self-assembly. Moreover, surface-anchored oligonucleotides could sequence-specifically initiate the growth of DNA origamis of specific sizes and shapes. Our work opens up new opportunities for encoding information into a surface and expressing the information into complex DNA surface architectures for potential nanoelectronics and nanophotonics applications. In addition, our new approach to surface confinement may facilitate the 2D self-assembly of other molecular components, such as proteins, as maintaining conformational freedom may be a general challenge in the self-assembly of complex structures at surfaces.</b><br><br>


Author(s):  
M. Kessel ◽  
R. MacColl

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.


Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.


MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.


2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>


2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>


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