Molecular basis of load carriage in articular cartilage

Overview

Topic status: We're looking for students to study this topic.

Articular cartilage (AC) is a connective tissue that protects the ends of long bones (e.g., femur or tibia). It plays a crucial role in the biomechanical mobility of humans. Understanding of the fundamental biophysical mechanisms of load carriage in cartilage is important for the design of tissue-engineered cartilage and the development of novel therapies for osteoarthritis. AC consists mostly of water (65%), but its unique properties are determined by a cross-linked scaffold of two biological polymers, collagen and proteoglycans. This biopolymeric scaffold provides rigidity and elasticity to the tissue and enables cartilage to reduce the stress on the bones it covers by distributing mechanical load over a large area.

Hypotheses/Aims

The principal aim of this project is to gain insights into the role of the three-dimensional architecture of the collagen/proteoglycan scaffold in determining the ability of cartilage to carry mechanical load. To achieve this aim, you will conduct magnetic resonance microimaging (micro-MRI) experiments probing molecular organisation of AC under compression in vitro.

Approach

The focus will be primarily on two micro-MRI techniques, spin-relaxation mapping and diffusion-tensor imaging, both of which probe the anisotropy of collagen alignment within the AC scaffold. The idea is to use these imaging techniques to obtain a 3D, spatially-resolved map of the changes in collagen alignment that occur under compression. By performing the imaging for different samples and different compression regimes, you will be able to obtain a comprehensive picture of how the 3D organisation of the macromolecular scaffold determines the functional behaviour of cartilage.

There are many sub-projects available within this project, including (but not limited to):

  1. Development of methodology for interpretation of spin-relaxation maps of the joint as a whole in order to evaluate the 3D organisation of the collagen fibre network throughout the entire joint;
  2. Development of the MRI cartilage consolidometer - a purpose-built, world-first instrument built in collaboration with the Engineering Faculty and used for mechanical testing of cartilage;
  3. Development of efficient algorithms for processing and visualisation of spin-relaxation and diffusion-tensor measurements;
  4. Simulations of the molecular hydrodynamics of water in AC and their use for quantitative interpretation of MRI measurements (see the next project description);
  5. Ultrasound imaging of compressed AC (with Prof Chris Langton);
  6. Development of trial methodology for identifying cartilage degradation, including models of osteoarthritis.

References

  1. SK de Visser, RW Crawford, JM Pope. Osteoarthr. Cartilage 16, 83-89 (2008)
  2. SK de Visser, JC Bowden, E Wentrup-Byrne, L Rintoul, T Bostrom, JM Pope, KI Momot. Osteoarthr. Cartilage 16, 689-697 (2008)
  3. K.I. Momot, J.M. Pope and R.M. Wellard. Digital processing of diffusion-tensor images of avascular tissues. In: Medical Image Processing: Techniques and Applications; G. Dougherty, Editor. ISBN 978-1-4419-9769-2. Springer (2011)
Study level
Honours
Supervisors
QUT
Organisational unit

Science and Engineering Faculty

Research area

Chemistry

Contact
Please contact the supervisor.