Funded PhD Fellowships in Computational Modelling of Polymer- and Metal-based Bioresorbable Vascular Scaffold Implants

The Biomechanics Research Centre at the National University of Ireland, Galway are seeking expressions of interest for several funded-PhD positions in computational modelling of polymer- and metal-based bioresorbable vascular scaffolds, as part of a larger EU Horizon-2020 consortium project.

Compared to permanent bare-metal stents, the design of the next-generation of drug-eluting bioresorbable vascular scaffold implants is complicated by the range of interacting physiochemical parameters that control material degradation in both polymer- and metal-based devices. Capturing the effects of the in vivo environment on bulk- or surface-based degradation mechanisms of polymer and metal-based bioresorbable materials through computational simulation presents significant challenges. While current phenomenological-based approaches to polymer- and metal-based degradation have provided reasonable predictions of mechanical performance, they heavily rely upon calibration of suitable material parameters to macroscopic experimental material degradation data. The overarching aim of this project develop physically-based modelling framework for polymer- and metal-based bioresorbable vascular scaffold implants and use it to predict long-term in vivo performance of drug-eluting BVS. Expressions of interest are sought for two funded PhD candidates in the following areas:

 (i)    Degradation Modelling of Polymer-Based Bioresorbable Vascular Scaffolds

This project will predict the long-term mechanical performance of an implanted polymer-based bioresorbable vascular scaffold, through the development of a multiphysics finite element modelling framework. This model will be implemented by the utilisation of several user-defined subroutines (USDFLD, UMAT), whereby chemical degradation mechanisms (described mathematically) will be coupled to the material constitutive law, resulting in progressive deterioration of mechanical properties. Model parameters will be determined through in vitro accelerated degradation testing, which will characterise temporal changes in material properties of a medical grade polymer through a range mechanical and physiochemical characterisation techniques.

 (ii)  Degradation Modelling of Metal-Based Bioresorbable Vascular Scaffolds

This project will predict the long-term mechanical performance of an implanted metal-based bioresorbable vascular scaffold, through the development of a multiphysics finite element modelling framework. This model will capture surface-based corrosion of magnesium-based bioresorbable devices and will be implemented through a combination of user-defined subroutines (USDFLD, UMAT) and an Arbitrary-Lagrangian-Eularian adaptive meshing technique to enable material loss on the corroding surface. Model parameters will be determined through in vitro accelerated degradation testing to characterise spatial and temporal effects of corrosion in metallic specimens using mechanical and physiochemical characterisation techniques.

Candidates interested at the Ph.D. level should have a degree in Biomedical Engineering or Mechanical Engineering, or closely-related discipline. Prospective candidates should be highly-motivated to participate in computational and/or experimental research related to the material degradation and medical device design. Experience in the following areas would be beneficial:

·         Finite Element Analysis (Abaqus/Comsol experience desirable)

·         Experimental Characterisation (mechanical and/or physiochemical techniques)

·         Programming languages (e.g. Matlab, Python or FORTRAN)

Please send expressions of interest to Dr. Ted Vaughan (ted.vaughan(at)nuigalway.ie), in a single PDF document that includes a one-page cover letter discussing research interest/experiences, suitability to the fellowship and a two-page CV.

Final applications will be submitted at a later date. The expected start dates for both projects is early 2018