Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner.
The standard model for the structure of collagen in tendon is an ascending hierarchy of bundling. Collagen triple helices bundle into microfibrils, microfibrils bundle into subfibrils, and subfibrils bundle into fibrils, the basic structural unit of tendon. This model, developed primarily on the basis of x-ray diffraction results, is necessarily vague about the cross-sectional organization of fibrils and has led to the widespread assumption of laterally homogeneous closepacking. This assumption is inconsistent with data presented here. Using atomic force microscopy and micromanipulation, we observe how collagen fibrils from tendons behave mechanically as tubes. We conclude that the collagen fibril is an inhomogeneous structure composed of a relatively hard shell and a softer, less dense core.
Gutsmann
Thomas
T
Department of Physics, University of California, Santa Barbara, California 93106, USA. tguts@physics.ucsb.edu.
Fantner
Georg E
GE
Venturoni
Manuela
M
Ekani-Nkodo
Axel
A
Thompson
James B
JB
Kindt
Johannes H
JH
Morse
Daniel E
DE
Fygenson
Deborah Kuchnir
DK
Hansma
Paul K
PK
D000818:Animals; D016880:Anisotropy; D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure*; D046911:Macromolecular Substances; D008846:Micromanipulation / Q000379:methods*; D018625:Microscopy, Atomic Force; D011487:Protein Conformation; D051381:Rats; D013710:Tendons / Q000737:chemistry* / Q000648:ultrastructure*; D016474:Weight-Bearing
D046911:Macromolecular Substances; D003094:Collagen