A clinically-relevant musculoskeletal humanoid shoulder for studying joint instabilities and diseases

project overview

Shoulder dislocations are events which most typically affect younger adults, although can occur in people of all ages. Dislocations occur in those with predispositions due to joint hypermobility ('born loose") and in those who sustain a significant traumatic event ("torn loose"). When a dislocation occurs there is usually damage sustained to the glenoid cartilage, labro-capusular structures, and humeral bone. They can predispose to future instability and osteoarthritis (OA). Treatments currently aim to repair torn labro-capsular structures, but no treatments currently exist to address the cartilage or bone damage on the glenoid or humerus.

Tissue engineering is a promising repair strategy that involves the development of bioreactors that generate tendon tissue in vitro using the patient's cells, scaffolds and mechanical stimulation. Current bioreactors mostly provide uniaxial cyclic loadings, while evidence suggests that they should provide multiaxial stresses, similar to those found physiologically. In this context, we have recently developed a unique bioreactor system that uses a musculoskeletal (MSK) humanoid robotic arm to mimic the motion and forces observed at the human shoulder joint and actuate cell-materials samples (EPSRC-funded Humanoid Bioreactor project, EP/S003509/1; see references below).

MSK humanoids aim to replicate the inner structures and the biomechanics of the human body using string actuators. They have seen major developments in recent years but have not been originally designed for biomedical applications and therefore need improvement. For instance, MSK humanoid shoulders offer a limited range of motion, in part due to the poor design of the joint capsule and the fact that the scapula has not been replicated. Mimicking more closely the human shoulder's biomechanics and anatomy would be greatly beneficial to our investigation of the potential of these robotic systems for biomedical applications. Besides its use for tissue engineering application, the novel joint bioreactor could lead to an improved in vitro tissue culture platform for studing joint disease such as OA and for testing implants.

This PhD project will focus on the development of a clinically relevant shoulder model combine with a bioreactor chamber suitable for the study of shoulder joint disease. The main goals of the project are as follow:
1) Designing a suitable joint capsule that also acts as a bioreactor chamber by taking into account the anatomy and biomechanics of the human shoulder.
2) Evaluate the performances (range of motions and forces) of the novel biomimetic robotic shoulder through a motion study and compare them to the human shoulder and the original (unmodified) robotic shoulder.
3) Identify and characterise an existing biphasic biomaterial for bone and cartilage growth (osteochondral scaffold) that can be positioned in the glenoid cavity
4) Demonstrate the potential of the novel robotic bioreactor shoulder for studying shoulder instability and OA in the presence of healthy or diseased human cells and under clinically relevant mechanical stimulation
5) Characterise the cell-scaffold contructs through viability assays, mechanical testing, histology, gene expression analysis, confocal microscopy, scanning electron microscopy, etc.

This is a highly multidisciplinary project that involves various aspects of tissue engineering and biomechanics. Although a clear end medical application is proposed here, a much wider range of biomedical applications might benefit from this work, including implant testing and mechanotransduction studies.

keywords

humanoid robots, motion studies, bioreactors, shoulder joint disease, biomaterials

training opportunities

The student will be able to learn about the hardware and software involved in the MSK robotic platform developed by Devanthro.They will be able to participate to relevant workshops such as biomechanics (3D motion capture techniques and motion analysis), CAD design and 3D printing. They will be trained for basic biological and physical assays for tissue construct and material characterisation.

The student will be encouraged to take skill training modules offered by the Medical Science Division (www.medsci.ox.ac.uk/study/skillstraining) and the university. These include topics such as how to meet the standards of excellent research, how to safely use research equipment and how to work effectively in their research environment. As part of their continuous learning and training, the student will contribute to regular group meetings and departmental seminars through presentations and research discussions. They will also participate in other events typically attended by the host groups such as conferences and outreach events (e.g. open days).

Further expertise in biomechanics, tissue engineering and solid-fluid mechanics will be accessible through the network of experts collaborating on the Humanoid Bioreactor project (across NDORMS, Engineering Science and the Mathematical Institute).   The student will have access to all NDORMS’s facilities, which include wet laboratories for material and tissue culture work as well as laboratories mechanical characterisation and motion studies. The student will have access to a shared engineering workshop and various 3D printers.

The supervisory team will include:

• Prof Pierre-Alexis Mouthuy, with expertise in bioengineering, biomaterials and bioreactors. His multidisciplinary team includes bioengineers, computational engineers, medical doctors, textile scientists and biotechnicians.
• Dr Julie Stebbins, expertise in motion capture in the field of clinical biomechanics, including gait and upper limb. (See: https://www.ndorms.ox.ac.uk/research/research-groups/roam)
• Prof Steve Gwilym: is an expert shoulder surgeon and clinician scientist with a research interest in shoulder trauma, pain and osteoarthritis

External support and supervision will also be available at Devanthro through Mr Rafael Hostettler, CEO, with expertise in musculoskeletal humanoid robots and leading the Roboy musculoskeletal robot project.

key publications

1. P.-A. Mouthuy, S. Snelling, R. Hostettler, A. Kharchenko, S. Salmon, A. Wainman, J. Mimpen, C. Paul, A. Carr, Humanoid robots to mechanically stress human cells grown in soft bioreactors, Communications Engineering 1(1) (2022) 2.
2. I.L. Sander, N. Dvorak, J.A. Stebbins, A.J. Carr, P.-A. Mouthuy, Advanced Robotics to Address the Translational Gap in Tendon Engineering, Cyborg and Bionic Systems 2022 (2022) 9842169.
3. P.-A. Mouthuy, A. Carr, Growing tissue grafts on humanoid robots: A future strategy in regenerative medicine?, Science Robotics 2(4) (2017).

contact information of all supervisors

Email

Pierre-Alexis Mouthuy Email – pierre-alexis.mouthuy@ndorms.ox.ac.uk

Julie Stebbins Email – Julie.stebbins@ndorms.ox.ac.uk

Steve Gwilym Email – steve.gwilym@ndorms.ox.ac.uk