In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging

2016 ◽  
Vol 18 (24) ◽  
pp. 16353-16360 ◽  
Author(s):  
Congheng Chen ◽  
Ting Yao ◽  
Sidong Tu ◽  
Weijie Xu ◽  
Yi Han ◽  
...  
Keyword(s):  
Phase Separation ◽  
Solid State Nmr ◽  
Random Coil ◽  
Rich Domain ◽  
Microscopic Studies ◽  
Helix Conformation ◽  
Phase Behaviors ◽  
Protein Rich ◽  
Β Sheet

SF was incompatible with PEG in some extent, and the phase separation took place in their blend film. The conformation of SF in the interface between SF and PEG was changed to the β-sheet, while that in the protein-rich domain remained in the random coil and/or helix conformation.

Conformational Preferences of Aβ25-35 and Aβ35-25 in Membrane Mimicking Environments

2019 ◽  
Vol 26 (5) ◽  
pp. 386-390
Author(s):  
Dhandayuthapani Sambasivam ◽  
Senthilkumar Sivanesan ◽  
Sayeeda Sultana ◽  
Jayakumar Rajadas
Keyword(s):  
Structural Transition ◽  
Conformational Transition ◽  
The Other ◽  
Random Coil ◽  
Structural Modifications ◽  
Sds Micelles ◽  
Conformational Preferences ◽  
Helix Conformation ◽  
Α Helix ◽  
Β Sheet

Background: The structural transition of aggregating Abeta peptides is the key event in the progression of Alzheimer’s Disease (AD). Objective: In the present work, the structural modifications of toxic Aβ25-35 and the scrambled Aβ35-25 were studied in Trifluoroethanol (TFE) and in aqueous SDS micelles. Methods: Using CD spectroscopic investigations, the conformational transition of Aβ25-35 and Aβ35-25 peptides were determined in different membrane mimicking environments such as TFE and SDS. An interval scan CD of the peptides on evaporation of TFE was performed. TFE titrations were carried out to investigate the intrinsic ability of the structural conformations of peptides. Results: We show by spectroscopic evidence that Aβ25-35 prefers beta sheet structures upon increasing TFE concentrations. On the other hand, the non-toxic scrambled Aβ35-25 peptide only undergoes a transition from random coil to α-helix conformation with increasing TFE. In the interval scan studies, Aβ25-35 did not show any structural transitions, whereas Aβ35-25 showed transition from α-helix to β-sheet conformation. In membrane simulating aqueous SDS micelles, Aβ25-35 showed a transition from random coil to α-helix while Aβ35-25 underwent transition from random coil to β-sheet conformation. Conclusion: Overall, the current results seek new insights into the structural properties of amyloidogenic and the truncated sequence in membrane mimicking solvents.

Spider prey-wrapping silk is an α-helical coiled-coil/β-sheet hybrid nanofiber

2018 ◽  
Vol 54 (76) ◽  
pp. 10746-10749 ◽  
Author(s):  
B. Addison ◽  
D. Onofrei ◽  
D. Stengel ◽  
B. Blass ◽  
B. Brenneman ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Coiled Coil ◽  
Secondary Structures ◽  
Random Coil ◽  
Hybrid Nanofiber ◽  
Β Sheet ◽  
Total P

Solid-State NMR results on 13C-Ala/Ser and 13C-Val enriched Argiope argentata prey-wrapping silk show that native, freshly spun aciniform silk nanofibers are dominated by α-helical (∼50% total) and random-coil (∼35% total) secondary structures, with minor β-sheet nanocrystalline domains (∼15% total).

Solid‐State NMR and MRI Spectroscopy for Li/Na Batteries: Materials, Interface, and In Situ Characterization

2021 ◽  
pp. 2005878
Author(s):  
Xiangsi Liu ◽  
Ziteng Liang ◽  
Yuxuan Xiang ◽  
Min Lin ◽  
Qi Li ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
In Situ Characterization

scholarly journals 13C Solid-State NMR Analysis of the Chemical Structure in Petroleum Coke during Idealized In Situ Combustion Conditions

ACS Omega ◽  
2021 ◽  
Author(s):  
Jingjun Pan ◽  
Guangzhi Liao ◽  
Rigu Su ◽  
Sen Chen ◽  
Zhengmao Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Petroleum Coke ◽  
Solid State Nmr ◽  
Chemical Structure ◽  
Nmr Analysis ◽  
In Situ Combustion

Rubber-modified epoxies: In situ detection of the phase separation by differential scanning calorimetry

Polymer ◽  
1993 ◽  
Vol 34 (18) ◽  
pp. 3960-3961 ◽  
Author(s):  
Dong Pu Fang ◽  
C.C. Riccardi ◽  
R.J.J. Williams
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Separation ◽  
Scanning Calorimetry ◽  
In Situ Detection

Structure of Microphase-Separated Silica/Siloxane Molecular Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Dale W. Schaefer ◽  
James E. Mark ◽  
David Mccarthy ◽  
Li Jian ◽  
C. -C. Sun ◽  
...  
Keyword(s):  
Phase Separation ◽  
Kinetic Studies ◽  
Organic Content ◽  
Small Particles ◽  
X Ray ◽  
Filled Elastomers ◽  
Polymeric Networks ◽  
Large Particles ◽  
Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

Influence of Post-Treatment with Methanol Vapor on the Properties of SF/P(LLA-CL) Nanofibrous Scaffolds

2011 ◽  
Vol 236-238 ◽  
pp. 2221-2224
Author(s):  
Kui Hua Zhang ◽  
Xiu Mei Mo
Keyword(s):  
Electrospun Nanofibers ◽  
Random Coil ◽  
Methanol Vapor ◽  
Nanofibrous Scaffolds ◽  
Nanofibrous Structure ◽  
Α Helix ◽  
Β Sheet ◽  
Ideal Method ◽  
C Nmr

In order to improve water-resistant ability silk fibroin (SF) and SF/P(LLA-CL) blended nanofibrous scaffolds for tissue engineering applications, methanol vapor were used to treat electrospun nanofibers. SEM indicated SF and SF/ P(LLA-CL) scaffolds maintained nanofibrous structure after treated with methanol vapor and possessed good water-resistant ability. Characterization of 13C NMR clarified methanol vapor induced SF conformation from random coil or α- helix to β-sheet. Moreover, treated SF/ P (LLA-CL) nanofibrous scaffolds still kept good mechanical properties. Methanol vapor could be ideal method to treat SF and SF/ P(LLA-CL) nanofibrous scaffolds for biomedical applications.

Fabrication and Characterization of Vitamin E TPGS Loaded Silk Fibroin/Hyaluronic Acid Nanofibrous Scaffolds

2013 ◽  
Vol 721 ◽  
pp. 274-277
Author(s):  
Li Li Ji ◽  
Qiao Ling Li ◽  
Zeng Hu Yang ◽  
Wei Jing Hu ◽  
Kui Hua Zhang
Keyword(s):  
Hyaluronic Acid ◽  
Vitamin E ◽  
Silk Fibroin ◽  
Ethanol Vapor ◽  
Random Coil ◽  
Burst Release ◽  
Nanofibrous Scaffolds ◽  
Vitamin E Tpgs ◽  
Polyethylene Glycol 1000 ◽  
Β Sheet

Vitamin E d-alpha-tocopheryl polyethylene glycol 1000 succinate (VE TPGS) loaded silk fibroin (SF)/ hyaluronic acid (HA) nanofibrous scaffolds were fabricated by means of electrospinning to biomimic the natural extracellular matrix. Scanning electronic microscopy (SEM) results indicated that electrospun VE TPGS loaded SF/HA nanofibers were ribbon-shaped, the width of nanofibers decreased slightly with the addition of VE TPGS to SF/HA blended solutions. Fourier transform infrared (FTIR) spectroscopy and Wide-angle X-ray diffraction (WAXD) curves revealed that VE TPGS did not induce SF conformation from random coil to β-sheet. SF conformation converted from random coil to β-sheet after being treated with 75% ethanol vapor. In vitro release studies confirmed VE TPGS had no obvious burst release and present good release behavior.

In situ Solid-State NMR Studies of Photocatalytic Oxidation Reactions

ChemInform ◽  
2006 ◽  
Vol 37 (26) ◽  
Author(s):  
Sarah Pilkenton ◽  
Daniel Raftery
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Photocatalytic Oxidation ◽  
Oxidation Reactions ◽  
Nmr Studies
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