Contact and non-contact atomic-force microscopy of type I collagen

1993 ◽  
Vol 51 ◽  
pp. 518-519
Author(s):  
Ellen A.G. Chernoff ◽  
Donald A. Chernoff ◽  
Kevin Kjoller
Keyword(s):  
Type I Collagen ◽  
Matrix Material ◽  
Practical Method ◽  
Type I ◽  
Collagen Gels ◽  
Santa Barbara ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Skin Collagen

Introduction. Type I collagen was examined using two types of atomic force microscopes (AFM) in a continuing effort to refine the process of obtaining molecular information from biological materials using scanning probe microscopy. Operating in air, a contact mode (Nanoscope II) and a non-contact mode AFM (Nanoscope III) were used to image collagen fibrils polymerized from pepsin-extracted type I bovine skin collagen adsorbed onto mica substrates. AFM is a practical method for high resolution examination of extracellular matrix material without the time consuming preparative techniques required for electron microscopy.Methods. For fibrillar collagen samples, Vitrogen 100 (Collagen Corporation, Palo Alto, CA) was prepared according to a modification of the procedure provided by Collagen Corp. for neutralized isotonic collagen gels. Monomeric collagen samples were prepared by diluting the vitrogen in 0.012M HCl.Images captured with the Nanoscope II AFM (Digital Instruments, Santa Barbara, CA) used a “J” scanner (horizontal range of 120 um).

The Dynamics of Mgo Surface Faceting

1997 ◽  
Vol 3 (S2) ◽  
pp. 741-742
Author(s):  
Svetlana V. Yanina ◽  
Matthew T. Johnson ◽  
C. Barry Carter
Keyword(s):  
Elevated Temperatures ◽  
Film Growth ◽  
Heat Treatments ◽  
Santa Barbara ◽  
Contact Mode ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The {001} surface of magnesium oxide (MgO) has been the focus of numerous studies, which were prompted by the importance of MgO for its use as a substrate for thin film growth and also as a chemical catalyst. In the present work, atomic force microscopy (AFM) was used for studying the dynamics of surface processes of MgO which occur at elevated temperatures. AFM was chosen, in part, because it allows for imaging of topographical details at the atomic level with minimal sample preparation. Additionally, because the surface morphology of the same area was traced through a series of heat treatments, scanning electron microscopy analysis would be difficult because no conductive coating could be used (such a coating may have altered the surface between subsequent heat treatments).AFM images were recorded in contact mode, in air, on a Nanoscope III (Digital instruments, Santa Barbara, CA) using Si3N4 cantilevers (Ultralevers, Park Inst., Sunnyvale, CA) with a nominal applied force of 10-15 nN.

Effects of Hydration on Nanoscale Structural Morphology and Mechanics of Individual Type I Collagen Fibrils

2012 ◽  
Vol 1465 ◽  
Author(s):  
Joseph M. Wallace ◽  
Chad Harding ◽  
Arika Kemp
Keyword(s):  
Type I Collagen ◽  
Type I ◽  
Mechanical Function ◽  
Structural Morphology ◽  
Force Microscopy ◽  
Atomic Force ◽  
Individual Type ◽  
Nanoscale Structure ◽  
Tail Tendon ◽  
Morphology And Mechanical Properties

ABSTRACTType I collagen is one of the most vital proteins in our bodies and serves a number of structural roles. Despite collagen’s importance, little is known about its nanoscale morphology in tissues and how morphology relates to mechanical function. This study directly probes nanoscale structure and mechanics in collagen as a function of hydration utilizing atomic force microscopy investigations of the mouse tail tendon. We demonstrate that collagen morphology and mechanical properties at the nanoscale change with dehydration, indicating that hydration is a factor which must be considered when performing studies at any length scale in collagen-based tissues. Studies are underway to further investigate this phenomenon and to determine how these properties change with disease in tendon and other Type I collagen-based tissues.

scholarly journals Influence of Matrix Metalloprotease on the Flexibility of Type I Collagen Fibrils Studied By Atomic Force Microscopy

2010 ◽  
Vol 98 (3) ◽  
pp. 29a
Author(s):  
Arkady Bitler ◽  
Emanuel Perugia ◽  
Inna Solomonov ◽  
Robert Visse ◽  
Joseph Orgel ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Type I Collagen ◽  
Collagen Fibrils ◽  
Type I ◽  
Matrix Metalloprotease ◽  
Force Microscopy ◽  
Atomic Force

Electric Field-Assisted Assembly of Type-I Collagen for Applications in Biomedical Micro-Systems

2005 ◽  
Author(s):  
Tiffany E. Miller ◽  
Eniko T. Enikov
Keyword(s):  
Electric Field ◽  
Type I Collagen ◽  
Negative Electrode ◽  
Positive Electrode ◽  
Type I ◽  
Solution Ph ◽  
Force Microscopy ◽  
Atomic Force ◽  
Micro Systems ◽  
Positively Charged

In the field of nanotechnology and applied engineering, an area that has received a great deal of attention is that of nanoassembly. The objective of this study was to demonstrate nanoassembly of type-I collagen on specified surfaces in response to an electric field. Two, otherwise identical, collagen solutions were prepared and adjusted to pHs of 5.5 and 8. The isoelectric fosusing point of collagen occurs at pH=6.7 which implies that the suspended collagen fibers in the aforementioned solutions possessed a net positive or negative charge, respectively. In each collagen solution, one volt was applied through a set of submerged electrodes for one minute. Atomic force microscopy was used to detect if and where assembly had occurred on the electrodes. The positively charged fibrils (pH=5.5) assembled on the negative electrode, but not on the positive electrode. The negatively charged fibrils (pH=8) assembled only on the positive electrode, but not on the negative electrode. In both cases, assembly occurred on the electrode of opposite charge of the suspended collagen fibrils, which was anticipated. The assembly of the positively charged fibrils (pH=5.5) on the cathode produced larger fibers than the fibers that were produced by the negatively charged fibrils (pH=8) on the anode. This indicated the more favorable environment for nanoassembly was the positively charged fibril solution (pH=5.5).

MORPHOLOGY OF ADSORBED COLLAGEN LAYERS OBSERVED BY ATOMIC FORCE MICROSCOPY

2009 ◽  
Vol 21 (05) ◽  
pp. 311-316
Author(s):  
Yih-Pey Yang ◽  
Chia-Chi Lin
Keyword(s):  
Atomic Force Microscopy ◽  
Type I Collagen ◽  
Fibrillar Structure ◽  
Collagen Molecule ◽  
Nanometer Scale ◽  
Type I ◽  
Force Microscopy ◽  
Atomic Force

The interaction between cells and biomaterials strongly depends on the assembled structure of collagen adsorption upon the solid surface. Due to its self-assembling property, Type I collagen may aggregate and form fibrils in vivo and in vitro. This study utilizes an atomic force microscope to investigate nanometer-scale organization of adsorbed Type I collagen layers on mica and on poly(methyl methacrylate) (PMMA). We have observed various film morphologies, depending on substrate hydrophobicity and the state of collagen solution used. On mica, the atomic force microscopy (AFM) study obtains dense felt-like structures of randomly distributed assemblies. Images of network-like assemblies composed of interwoven fibrils appear on PMMA. According to the above results, we believe that these assemblies are associated at the interface rather than aggregated in the solution. This work also investigates the adsorbed collagen structure on PMMA after collagen aggregation in solution, to realize the relation between adsorption and aggregation. Consequently, the result exhibits a dendritic fibrillar structure adsorbed on PMMA, following collagen molecule aggregation, to form a fibrillar structure in the solution. This result suggests that the adsorption of aggregates preformed in the solution is preferable to collagen molecules adsorption. This research created all assembled structures of adsorbed collagen layers in nanometer-scale thickness.

scholarly journals Extracellular matrix structure and nano-mechanics determine megakaryocyte function

Blood ◽  
2011 ◽  
Vol 118 (16) ◽  
pp. 4449-4453 ◽  
Author(s):  
Alessandro Malara ◽  
Cristian Gruppi ◽  
Isabella Pallotta ◽  
Elise Spedden ◽  
Ruggero Tenni ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Type I ◽  
Membrane Elasticity ◽  
Force Microscopy ◽  
Atomic Force ◽  
Biophysical Processes ◽  
Microscopy Analysis ◽  
Specific Receptors ◽  
Fibronectin Assembly ◽  
Platelet Formation

Abstract Cell interactions with matrices via specific receptors control many functions, with chemistry, physics, and membrane elasticity as fundamental elements of the processes involved. Little is known about how biochemical and biophysical processes integrate to generate force and, ultimately, to regulate hemopoiesis into the bone marrow-matrix environment. To address this hypothesis, in this work we focus on the regulation of MK development by type I collagen. By atomic force microscopy analysis, we demonstrate that the tensile strength of fibrils in type I collagen structure is a fundamental requirement to regulate cytoskeleton contractility of human MKs through the activation of integrin-α2β1–dependent Rho-ROCK pathway and MLC-2 phosphorylation. Most importantly, this mechanism seemed to mediate MK migration, fibronectin assembly, and platelet formation. On the contrary, a decrease in mechanical tension caused by N-acetylation of lysine side chains in type I collagen completely reverted these processes by preventing fibrillogenesis.

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