IMAGING, CHARACTERISATION AND ADDITIVE MANUFACTURE OF CARDIOVASCULAR PHANTOMS.

Lead Research Organisation: University of Birmingham
Department Name: Mechanical Engineering

Abstract

My previous research in biomedical engineering has concerned the mechanical properties of cartilage, and the pathology of osteoarthritis. Better understanding the mechanical properties of biological materials is paramount for accurate diagnosis of the severity of a disease, and the implications it may pose to the function or deterioration of relevant tissue or organ, as well as better estimating the chances of a total failure of the organ. Analysing and accurately modelling a tissue or organ can also aid the design of biological implants, for example the production of valve replacements which mimic the function and strength of a natural valve. The ability to combine these disciplines of mechanical testing and implant design, along with relatively new manufacturing techniques (such as additive manufacture) poses a fantastic opportunity to design patient specific implants or phantoms, both geometrically and mechanically - a possibility that I find fascinating. My aim for future research is to further current knowledge and understanding of the mechanical properties of biological materials, with the overall aim of contributing valuable research towards improving pre-clinical testing and implant design.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509590/1 01/10/2016 30/09/2021
2007667 Studentship EP/N509590/1 01/10/2017 30/09/2020 Joseph Crolla
 
Description Arterial tissue, as well as most other biological connective tissues are viscoelastic, meaning their mechanical response changes depending upon the rate at which a load is applied. Poly(vinyl alcohol) cryogel (PVAC) is a hydrogel has been extensively used to mimic arterial tissue, and has the potential to have a wide variation in mechanical properties. This study has been the first to successfully characterize the viscoelastic mechanical properties of PVAC using dynamic mechanical analysis (DMA) in order to further understand the potential of PVAC as a tissue mimicking material. Magnetic Resonance Imaging (MRI) is a technique that is widely used in both pre-clinical and clinical applications for both testing arterial phantoms (arterial mimics used in a wide variety of pre-clinical testing), as well as diagnosing and assessing atherosclerosis (the build up of a lipid plaque on the arterial wall). It is therefore important to understand how changes in composition of PVAC effect MRI properties. This study has also successfully analysed how the T2 relaxation time changes with different PVAC compositions, allowing the future characterisation of the composition of PVAC in phantoms and implants using a non-invasive method.
The purpose of this work on the characterisation of PVAC is to allow the potential to produce more complex heterogenous structures which will allow for a more accurate physical model of the coronary artery. This project has looked towards furthering the potential to use additive manufacturing processes for the production of complex structures. This project has successfully used a new technique to cryogenically additively manufacture that has previously been shown to work for PVAC (where the hydrogel freezes on contact with the print bed in order to hold its shape). This process has been used to create flat sheets of PVAC with anisotropic mechanical properties by varying the printing orientation. This should allow the additive manufacture of multiple layers each which mimic the mechanical properties of the different layers in the artery. This would produce a three-dimensionally anisotropic model, which would be a vast improvement over casting methods of manufacturing, which is only capable of reproducing the bulk properties of arterial tissue.
Exploitation Route PVAC is a commonly used material for the manufacture of arterial phantoms, as well as being a material used to model many other connective tissues. This work will allow others to make a more informed decision as to which composition of PVAC they need to use , based on how the viscoelastic properties of various compositions of PVAC compare to the tissue they are studying. This work also allows for the ability to produce more adaptable isotropic materials through additive manufacturing which will allow for more accurate models of connective tissue.
As PVAC is also biocompatible, and can therefore be used for implants, this work allows both the future ability to manufacture implants with accurate mechanical properties on a patient specific level. The work done in this project on MRI characterisation will also help towards the future potential for a patient's implant to be monitored non-invasively.
Sectors Education,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology