Why do bones break? The nanomechanics of osteoporotic bone fragility fracture
An opportunity has arisen for a 3-year PhD studentship within the Musculoskeletal Laboratory at Imperial College London. The studentship is funded by the Department of Surgery and Cancer at Imperial College London.
The proposed project will apply state if the art synchrotron imaging to investigate whether age related osteoporotic fracture risk might be better understood with an analysis of bone mechanics at the nanoscale.
Osteoporosis causes older people to break their bones leaving them unable to feed and dress themselves or take part in family life. It is well known that bone loss accompanies aging in both men and women and contributes to bone fragility. Our research suggests that changes in the mechanics of the bone matrix also contribute to fragility by making the material more brittle, and less able to deform before fracturing. Therefore, the aim of the PhD is to investigate whether and how alterations in bone nanoscale structure and mechanics associated with osteoporosis influence the whole bone scale.
The two key objectives are to characterise the nano-structure and mechanics of bone. At the most basic level bone matrix is made up of nanoscopic elastic collagen fibrils coated and embedded with mineral plates. Using Synchrotron imaging techniques in the particle accelerator at the Diamond Light Source (Didcot, UK) we have found that the mineral and collagen debond at a lower load in osteoporotic bone tissue – when compared to healthy controls. Hence the collagen-mineral bond appears to be the weakest link in bone structure. However, the type and strength of the bond has not been described. Hence a key step in the PhD will be to study the collagen mineral interaction.
The successful candidate will learn how will fracture bone samples from healthy aging and osteoporotic people in a synchrotron micro-CT scanner to capture mechanical properties. Then image the fracture surfaces using a range of microscopy techniques (including and not limited to SEM, TEM, XRD, FTIR or Raman) to characterise the collagen and mineral organisation. Finally, the spatial interaction between collagen and mineral phases will be characterised using thermogravimetric analysis.
The findings of the study will be important for helping clinicians to overcome the treatment gap for osteoporosis. Over half of patients are only diagnosed after suffering a fracture because the diagnostic tests (FRAX and DXA) do not identify everyone with fragile bone. Instead nanoscopic bone biopsies or in vivo spectroscopic techniques could be used to assess bone health in primary care.
The position is funded by the Department of Surgery and Cancer, Faculty of Medicine, Imperial College London. The successful candidate will be required to undertake anatomy teaching for MBBS undergraduate and postgraduate students.
Skills and Experience
The successful candidate will be enthusiastic to learn and develop research skills and use a range of imaging techniques to visualise bone structure and mechanics. Previous experience with any of the imaging techniques highlighted above would be an advantage.
Applicants must be EU nationals or have permanent leave to remain in the UK and should hold or expect to obtain a first or upper-second class honours degree or equivalent in imaging, biology, chemistry or engineering. A Master’s degree in one of the above fields would be advantageous.
The annual stipend will be £17,500.
Applicants should submit their CV and a covering letter, including full contact details of two referees, to Dr Richard L . Abel ([Email Address Removed]).
Imperial College PhD entry requirements must be met and the successful applicant will subsequently need to apply online.
For further information please contact Dr Richard L . Abel ([Email Address Removed]).
Closing date: 30th June 2019
Scientific Reports: https://www.nature.com/articles/srep43399