Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

CMPO Seminar - Collagen fibrils: liquid-crystals, paracrystals, and more

Andrew Rutenberg,
AC Fales Professor of Theoretical Physics
Dept. Physics;  Dalhousie Univ

Date: Thursday April 11th, 2019
Time: 1:30 p.m. 
Location: 
Stirling 201

Abstract:

Collagen fibrils are versatile self-assembled structures that provide mechanical integrity to mammalian tissues. Fibrils are much more interesting than cartoon-structures would indicate: the radius of collagen fibrils vary widely depending on experimental conditions or anatomical location; the tilt of individual molecules with respect to the fibril axis varies with radial distance in a “double-twist” configuration; and fibrils exhibit a robust periodic modulation of density along the axial direction -- the “D-band”.  With a liquid-crystalline Franck free energy we have described how the double-twist stabilizes the fibril phase and determines the fibril radius. By adding phase-field crystal terms we recover the D-band, and show how it distorts the double-twist field and vice-versa.  Significant open questions remain about how cross-linking stabilizes fibrils, and how mechanical damage localizes to the surfaces of fibrils.