Remodeling of the annulus fibrosus : orientational ordering in 2D polymeric networks on curved substrates

Abstract

The annulus fibrosus is an anisotropic tissue which is located at the outer side of the intervertebral disc. The annulus fibrosus is a highly oriented multi layered tissue made of organic fibers like collagen. Each layer consists of well ordered, parallelly oriented, collagen fibers, which are oriented at a specific angle in relation to the axis of the disc and spine. The ordered network of collagen fibers is created in the embryonic phase, where the fibers reorientate on a swelling cylindrical structure known as the notochord. We study the origin of the oriented order in the network and give special attention to the role of the macroscopic shape of the annulus fibrosus. We consider the annulus fibrosus as a single layered cylindrical network of discrete persistent chains, which is a discretized description of the worm-like chain. The energy of the discrete persistent chain consist of spring- and bending energy. To study the development of the annulus fibrosus we developed a code which simulates polymeric networks on the surface of a cylinder. The simulation starts with a network of randomly placed fibers. The results of the simulations show tilted alignment of the chains as a consequence of the bending due to the cylindrical shape. The influence of the cylindrical shape is confirmed by the effect of increasing the bending modulus. This resulted in higher order and steeper alignment.

Date of Award	31 Jan 2014
Original language	English
Supervisor	C. (Kees) Storm (Supervisor 1)