scholarly journals Observing Effects of Calcium/Magnesium Ions and pH Value on the Self-Assembly of Extracted Swine Tendon Collagen by Atomic Force Microscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xuan Song ◽  
Zhiwei Wang ◽  
Shiyu Tao ◽  
Guixia Li ◽  
Jie Zhu
Keyword(s):  
Atomic Force Microscopy ◽  
Metal Ions ◽  
Self Assembly ◽  
Food Packaging ◽  
Ph Value ◽  
The Self ◽  
Solution Ph ◽  
Collagen Concentration ◽  
Force Microscopy ◽  
Atomic Force

Self-assembly of extracted collagen from swine trotter tendon under different conditions was firstly observed using atomic force microscopy; then the effects of collagen concentration, pH value, and metal ions to the topography of the collagen assembly were analyzed with the height images and section analysis data. Collagen assembly under 0.1 M, 0.2 M, 0.3 M CaCl2, and MgCl2 solutions in different pH values showed significant differences (P < 0.05) in the topographical properties including height, width, and roughness. With the concentration being increased, the width of collagen decreased significantly (P < 0.05). The width of collagen fibers was first increased significantly (P < 0.05) and then decreased with the increasing of pH. The collagen was assembled with network structure on the mica in solution with Ca2+ ions. However, it had shown uniformed fibrous structure with Mg2+ ions on the new cleaved mica sheet. In addition, the width of collagen fibrous was 31~58 nm in solution with Mg2+ but 21~50 nm in Ca2+ solution. The self-assembly collagen displayed various potential abilities to construct fibers or membrane on mica surfaces with Ca2+ ions and Mg2+ irons. Besides, the result of collagen self-assembly had shown more relations among solution pH value, metal ions, and collagen molecular concentration, which will provide useful information on the control of collagen self-assembly in tissue engineering and food packaging engineering.

scholarly journals Effects of metal ions on the self-assembly of chitosan molecules investigated with atomic force microscopy

2018 ◽  
Vol 21 (1) ◽  
pp. 1986-1994
Author(s):  
Zhiwei Wang ◽  
Shengying Fei ◽  
Weisha Kong ◽  
Qi Xiao ◽  
Jie Zhu
Keyword(s):  
Atomic Force Microscopy ◽  
Metal Ions ◽  
Self Assembly ◽  
The Self ◽  
Force Microscopy ◽  
Atomic Force

NANOSTRUCTURES FROM DESIGNER PEPTIDES

COSMOS ◽  
2008 ◽  
Vol 04 (02) ◽  
pp. 173-183
Author(s):  
BOON TEE ONG ◽  
PARAYIL KUMARAN AJIKUMAR ◽  
SURESH VALIYAVEETTIL
Keyword(s):  
Atomic Force Microscopy ◽  
Solid State ◽  
Self Assembly ◽  
Size Range ◽  
The Self ◽  
Mica Surface ◽  
Force Microscopy ◽  
Solution Structures ◽  
Atomic Force

The present article reviews the self-assembly of oligopeptides to form nanostructures, both in solution and in solid state. The solution structures of the peptides were examined using circular dichroism and dynamic light scattering. The solid state assembly was examined by adsorbing the peptides onto a mica surface and analyzing it using atomic force microscopy. The role of pH and salt concentration on the peptide self-assembly was also examined. Nanostructures within a size range of 3–10 nm were obtained under different conditions.

scholarly journals Cation-Specific Effects on the Self-Assembly of Collagen Molecules Mediated by Acetate on Mica Surface Observed with Atomic Force Microscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Zhiwei Wang ◽  
Qi Xiao ◽  
Xuan Song ◽  
Yunfei Wan ◽  
Jie Zhu
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Ionic Concentration ◽  
Collagen Fibrils ◽  
The Self ◽  
Mica Surface ◽  
Force Microscopy ◽  
Specific Effects ◽  
Atomic Force ◽  
Base Method

The well-organized collagen layers on mica surface have drawn extensive attention for its essential applications and studies on the process of self-assembly as a model system. In this work, collagen extracted from fish scales by acid-base method was used to explore the self-assembly characters, and atomic force microscopy was applied to observe the collagen assembled on mica surface mediated by acetate with four different cations, including K+, Na+, Mg2+, and Ca2+. It showed that cations might influence the interaction between collagen fibrils and mica surface at high ionic concentration. And a similar network structure was acquired with uniform pore size for four kinds of acetates; nearly ranged collagen fibrils in the same direction were collected in Mg2+ solutions, while flat films with some fibrils were achieved in K+ solutions. The Hofmeister series and Collins’ model were adapted to explain the effects of cations and acetate on the self-assembly of collagen. These results and analysis would be helpful for directing the pattern of collagen assembly on a solid surface with a potential application in food science and engineering.

Single asperity tribochemical wear of silicon by atomic force microscopy

2009 ◽  
Vol 24 (1) ◽  
pp. 173-178 ◽  
Author(s):  
Futoshi Katsuki
Keyword(s):  
Atomic Force Microscopy ◽  
Frictional Force ◽  
Ph Value ◽  
Ph Dependence ◽  
Bond Rupture ◽  
Solution Ph ◽  
Crystal Silicon ◽  
Force Microscopy ◽  
Single Asperity ◽  
Atomic Force

Measurements of single asperity wear on oxidized silicon surface in aqueous potassium hydroxide (KOH) using atomic force microscopy (AFM), where the single crystal silicon tip was used both to tribologically load and image the surface, is presented. AFM was also operating in the lateral (frictional) force mode to investigate the pH dependence of kinetic friction between the tip and the SiO2 surface. It was shown that the Si tip wear amount strongly depended on the solution pH value and was at a maximum at around pH 10. It was also found that the Si removal volume in mol was approximately equal to that of SiO2 irrespective of the solution pH value. This equality implies that the formation of the Si–O–Si bridge between one Si atom of the tip and one SiO2 molecule of the specimen at the wear interface. The surface of the Si tip is then oxidized. Finally, the bond rupture by the tip movement will occur, the dimeric silica (OH)3Si–O–Si(OH)3, including the Si–O–Si bridge, is dissolved in the KOH solution. The frictional signal is also sensitive to the pH values of the solution and peaked at around pH 10. These results indicate that the removal behavior of the Si tip and SiO2 surface would be affected by the frictional force between the Si and the SiO2, because of an increased liquid temperature and a compressive stress in Si and SiO2 networks. Strong influence is observed by the pH of the ambient solution confirming the important role of the OH− in the wear mechanism. Pressure dependence of the microwear behavior under aqueous electrolyte solutions has also been investigated. A microscopic removal mechanism, which is determined by interplay of the diffusion of water in Si and SiO2, is presented.

Dynamic Self-Assembly Process of a Designed Peptide

2013 ◽  
Vol 750-752 ◽  
pp. 1630-1634
Author(s):  
Li Ping Ruan ◽  
Zhi Hua Xing
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Layer By Layer ◽  
Assembly Process ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sheet Structure ◽  
Β Sheet ◽  
Layer Assembly

In this paper, we reported the dynamic self-assembly process of an half-sequence ionic self-complementarity peptide CH3CO-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-NH2, which could self-assemble into stable nanofibers and formed hydrogel consisting of >99% water. The dynamic self-assembly process was detected by circular dichroism (CD) and atomic force microscopy (AFM). CD spectrum revealed that the mainly contents of the peptide were regular β-sheet structure. The data indicated that though the secondary structure of the peptide formed immediately, the microstructure of the self-assembly process of the designed peptide formed slowly. AFM image illustrated that the self-assembly process was layer-by-layer assembly.

Single Asperity Tribochemical Wear of Silicon by Atomic Force Microscopy

2007 ◽  
Vol 991 ◽  
Author(s):  
Futoshi Katsuki
Keyword(s):  
Atomic Force Microscopy ◽  
Frictional Force ◽  
Ph Value ◽  
Ph Dependence ◽  
Bond Rupture ◽  
Solution Ph ◽  
Crystal Silicon ◽  
Force Microscopy ◽  
Single Asperity ◽  
Atomic Force

ABSTRACTWe report measurements of single asperity wear on oxidized silicon surface in aqueous KOH using atomic force microscopy (AFM), where the single crystal silicon tip was used both to tribologically load and image the surface. AFM was also operating in the lateral (frictional) force mode (LFM) to investigate the pH dependence of kinetic friction between the tip and the SiO2 surface. We found that the Si tip wear amount strongly depended on the solution pH value and was at a maximum at around pH 10. It was also found that the Si removal volume in moles was approximately equal to that of SiO2 irrespective of the solution pH value. This equality implies that the formation of the Si-O-Si bridge between one Si atom of the tip and one SiO2 molecule of the specimen at the wear interface, followed by the oxidation of the Si surface, finally the bond rupture by the tip movement, the dimeric silica (OH) 3Si-O-Si(OH) 3, including the Si-O-Si bridge is dissolved in the KOH solution. It was also found the frictional force is highly sensitive to the pH values of the solution and peaked at around pH 10. These results indicate that the interfacial reaction would be affected by the frictional force between the Si tip and the SiO2 surface, due to an increased liquid temperature and a compressive stress in Si and SiO2 networks. Strong influence is observed by the pH of the ambient solution confirming the important role of the OH- in the wear mechanism. We present a microscopic removal mechanism which is determined by an interplay of the diffusion of water in Si and SiO2.

scholarly journals Immunoactivity of self-assembled antibodies investigated by atomic force microscopy

RSC Advances ◽  
2018 ◽  
Vol 8 (51) ◽  
pp. 29378-29384 ◽  
Author(s):  
Hiroaki Kominami ◽  
Kei Kobayashi ◽  
Shinichiro Ido ◽  
Hirokazu Kimiya ◽  
Hirofumi Yamada
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Two Dimensional ◽  
Igg Antibodies ◽  
Association Rate Constant ◽  
Association Rate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

We investigated self-assembly such as hexamerization and two-dimensional crystallization of immunoglobulin G (IgG) molecules on mica by atomic force microscopy. We also estimated the association rate constant of the self-assembled IgG antibodies.

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