Dr Daniel Espino BSc, PhD, SFHEA, CBiol, CSci, MRSB, CEng, MIPEM

• PhD in Biomedical Physics & Bio-Engineering, University of Aberdeen
• BSc, University of Aberdeen
• Senior Fellow of the Higher Education Academy SFHEA
• Member of the Institute of Physics and Engineering in Medicine C.Eng, MIPEM
• Member of the Royal Society of Biology C.Biol, C.Sci, MRSB
• Postgraduate Certificate in Academic Practice, University of Birmingham Distinction

Daniel's current research focus as an Associate Professor is shaped by his career path. This includes holding a Marie Curie Intra-European Fellowship at the University of Birmingham, Marie Curie Experienced Researcher post on the 3D Anatomical Human project at the Rizzoli Orthopedic Institute (Bologna, Italy), and Maurice & Phyllis Paykel Research Fellowship at the University of Auckland (New Zealand).

Daniel first became interested in the application of mechanics to physiology during his undergraduate studies at the University of Aberdeen. He held a Wellcome Trust Vacation scholarship, focusing his interests on the mechanics of the intervertebral disc through numerical modelling. Subsequently, he evaluated the mechanics of the mitral heart valve during his postgraduate studies. As an undergraduate he was awarded the Robertson prize for Physics (University of Aberdeen) and as a post-graduate the Best Poster prize at the 9th Annual Scientific Meeting of the Institute of Physics and Engineering in Medicine.

Following his PhD in Biomedical Physics & Bio-Engineering at the University of Aberdeen, Daniel was awarded a British Heart Foundation Junior Fellowship which he held at the University of Birmingham – marking the start of his affiliation with Mechanical Engineering; an affiliation which he resumed following posts in New Zealand and Italy.

Daniel is passionate about education, and was part of the Swift Feedback Team awarded a Teaching Innovation Award (2020) for the development of feedback software.

Teaching Programmes

• Year-1 School of Engineering
• Mechanical Engineering

In addition to his core teaching, Daniel has been active as regards outreach, for example delivering engineering sessions via In2Science, The Engineering Development Trust, and Birmingham’s own Popular Maths lectures.

Daniel is always keen to discuss research opportunities for potential researchers who are highly motivated and seeking opportunities in the field of tissue mechanics (refer to ‘Research Themes’ for more details).

Sample outputs produced by Daniel’s researchers, such as theses, videos, code and some of the awards which they have received are included below:

Sample PhD theses

• Multiphase cardiovascular haemodynamics: impact of surface roughness and platelet activation
• Combined numerical and morphological study of the heart: development of a scalable mitral valve morphometric model and assessment of modelling criteria for the right atrium
• Characterisation of coronary arteries: mechanical testing and three-dimensional imaging
• Bio-mechanical behaviour of articular cartilage: characterisation of surface damage, friction and replacement
• Biostability of an orthopaedic device and its long-term implantable biomaterials
• Combined numerical and morphological study of the lumbar spine: parametric finite element model and evaluation of dynamic implants

Prizes awarded to Daniel’s researchers

• The three-minute thesis people’s choice award to Diana Cruz de Oliveira (2020) for her work on mitral valve modelling
• The Michael K. O'Rourke prize (College of Engineering and Physical Sciences) for best PhD publication to Carolina Lavecchia for her paper on modelling of the lumbar spine: Lavecchia et al., 2018
• CVET Most Downloaded Article Award, a Prize jointly awarded by the Biomedical Engineering Society (BMES) and Springer-Nature (2018 BMES Conference, Atlanta, GA, USA). For work on coronary artery mechanics and surface imaging: Burton et al., 2017
• Best Poster Award at the 23rd Congress of the European Society of Biomechanics, Sevilla, Spain, July 2nd –5th, 2017. This work on the correlation between bone histomorphology and the dynamics of articular cartilage formed a section of the work subsequently published here: Fell et al., 2019

Featured issue covers

• Journal of the Royal Society Interface, August 2020, Volume 17, Issue 169. For modelling of blood flow over coronary artery surfaces: Owen et al., 2020
• Computer Methods in Biomechanics and Biomedical Engineering, 2015, Volume 18, Issue 12. For modelling of the bicuspid aortic valve: Kuan & Espino, 2015
  

Release of code for modelling

• Lumbar model generator (Lavecchia et al., 2018).
  The links provide matlab code for generating models suitable for FEA of the lumbar spine:
  https://github.com/CELavecchia/LMG and https://doi.org/10.5281/zenodo.835879
• Mitral valve toolbox (de Oliveira, Espino et al., 2021)
  The link provides matlab code for generating models suitable for FEA of the mitral heart valve.
• FEA model for Trigger Finger (Relf et al., 2020)
  The supplementary file included with the publication is an Abaqus file for FEA of Trigger Finger: stenosing tenosynovitis.

Sample presentations

• Presentation by Dr David Owen on blood flow modelling over cardiovascular surfaces
• Presentation by Dr Diana de Oliveira on blood flow modelling through hemodialysis catheters

Daniel’s research is broadly focused on the mechanics of connective tissues – noting that blood itself is a classed as a connective tissue. This has led to a wide range of studies on individual tissues, organs and physiological systems; with experimental and computational platforms being developed to study the mechanics of their function or failure, and potential applications to either surgery or medical devices.

Specific examples of the application of experimental and computational techniques include evaluating:

• the mechanics of the mitral heart valve including its surgical repair;
• the mechanics of the intervertebral disc and a posterior stabilisation device,
• dynamics and failure mechanics of articular cartilage,
• blood-flow using a numerical model, including its application to the design of hemodialysis catheters.

Selected case-studies highlighting current research activities are included below.

Experimental and computational platforms to evaluate connective tissue mechanics

An experimental method to test mitral heart valves in vitro has been developed and used to evaluate surgical repair of the mitral valve, and chordal failure. This has been matched by a fluid-structure interaction model leading to predict flow through the mitral valve, and finite-element analysis modelling of the valve itself.

Figure 1: Experimental and computational modelling of an otherwise healthy mitral valve. A two-dimensional plane of blood flow through the valve has been predicted using Fluid-Structure Interaction during diastole. The stress distribution on the mitral valve has been mapped on to half of the left atrial view of the mitral valve anterior and posterior leaflets, during systole. Tests consisted of a porcine mitral heart valve placed within an experimental simulator to mimic peak systolic pressure exerted on the valve. The central figure has been reproduced from Northeast et al., 2021.

Application of Computational Fluid Dynamics to evaluate blood-flow

Daniel’s team have applied their blood models to develop a numerical platform with which to evaluate the effectiveness of the design of hemodialysis catheter tips, exploiting a multi-phase Eulerian-Eulerian model.

Figure 2: Development of a numerical platform to evaluate transient blood-flow through hemodialysis catheters, using a right atrium model. A multiphase blood model has been used to model blood in this Computational Fluid Dynamics simulation, with the volume fraction of recirculated blood evaluated. Reproduced from de Oliveira, Owen et al., 2021.

While the team have used a Newtonian model for blood for large scale-flow, and for Fluid-Structure Interaction models, these models have limitations when evaluating disease states such as aneurysms or where a medical device might damage a specific blood component, such as causing hemolysis. Instead, multiphase models have been employed to better mimic blood constituents – and their distribution during flow. The figure, below, shows the evaluation of hematocrit distribution predicted using Computational Fluid Dynamics along a micro-scale surface.

Figure 3: Micro-scale reconstruction of the wall of a descending left coronary artery, and evaluation of hematocrit distribution predicted using computational fluid dynamics. The surface reconstruction is of a porcine coronary artery endothelial surface, with the physical data obtained using Atomic Force Microscopy.  Figures reproduced from Burton et al., 2019  & Owen et al., 2020.

More recently a discrete, Lagrangian phase matching the density of platelets has been included in Eulerian-Eulerian blood models. This has allowed the identification of regions in a constricted blood vessel where the tracked particles experiencing high-shear stress and high residence time can be identified, in combination with the red blood cell phase experiencing low-shear strain rates. See the animation of platelet flow showing exposure to sufficiently low aggregatory shear levels (<50 s^-1) in the diseased MKM5 coronary artery bifurcation.

Dynamic mechanical analysis of soft connective tissues

Daniel is interested in the dynamics of soft tissues. An example as applied to orthopaedics, is on how the dynamics of articular cartilage links to its underlying bone; particularly fast-response loading which may be relevant to activities such as walking, and faster-loading still which may relate to trauma.

Figure 4: Experimental workflow for the analysis and experimental testing of human articular cartilage obtained from a femoral head. Reproduced from Mountcastle et al., 2019 .

Findings from these studies have implications for the energy transfer from articular cartilage to its subchondral bone, which may subsequently affect the mechanisms of failure observed. Water content, in particular, appears to have a key role in osteochondral dynamics, affecting not only how energy is dissipated but also how it is stored during recoil following loading. A key point is that the mechanics of articular cartilage differ when loaded under non-equilibrium conditions as associated with fast-response loading... for instance, when you go for a walk!

Figure 5: Experimental data obtained from the articular cartilage workflow. Including: [1] sample data obtained from micro-CT when comparing articular-cartilage-on-bone cores from across the tibial plateau; [2] sample hysteresis data obtained for articular cartilage when tested at physiological loading rates and above/below this range; [3] sample data evidencing that water content in articular cartilage alters its mechanical behaviour in terms of measures characterising its ability to store (k’) and dissipate (k’’) energy during dynamic mechanical analysis.
Reproduced from Fell et al., 2019, Lawless et al., 2017 & Crolla et al., 2022.

Daniel currently serves on the following editorial boards:

• BMC Musculoskeletal Disorders;
• Journal of Healthcare Engineering;
• Nonlinear Engineering. Modeling and Application.

Daniel is currently serving on both the Course Accreditation Committee and Engineering Course Accreditation Panel for the Institute of Physics and Engineering in Medicine.