«Biotribology of the Natural Ankle Joint Nivedah Kuganenderan; Claire Brockett; Joanne Tipper; John Fisher Institute of Medical and Biological ...»
Biotribology of the Natural Ankle Joint
Nivedah Kuganenderan; Claire Brockett; Joanne Tipper; John Fisher
Institute of Medical and Biological Engineering, The University of Leeds,
Leeds LS2 9JT UK
Ankle osteoarthritis (OA) is the most common form of arthritis and is a
major cause of morbidity and disability (Buckwalter, et al., 2004), of
which 4% of adult population in the UK are suffering from (Valderrabano
& Horisberger, 2011). It is characterised by the progressive destruction of articular cartilage, leading to joint space narrowing, subchondral sclerosis, subchondral cyst, synovial inflammation and osteophyte formation (Buckwalter & Mankin, 1998).
The aim of the project is to investigate tribology, contact mechanics and geometry of the natural ankle joint.
A novel functional biomechanical and biotribological model for the function of tibio-talar aspect will be developed. Comparison with hip and knee biotribological studies will be made.
Geometric measurements of ankles will be made prior to carrying out any testing procedures. Dimensional indentation testing and pin-on-plate device will be used to study mechanical characterisation and tribological quantities respectively.
Currently existing clinical interventions on ankle arthritis are considered to be unsuccessful due to limited research. Hence, further research into the biotribological aspect of the natural ankle joint needs to be established in order to develop treatment options for ankle arthritis.
References Buckwalter, J. & Mankin, H., 1998. Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation. Instr Course Lect, Volume 47, pp. 487-504.
Buckwalter, J., Saltzman, C. & Brown, T., 2004. The impact of osteoarthritis: implications for Research. Clin Orthop Relat Res, Volume 427, pp. 6-15.
Valderrabano, V. & Horisberger, M., 2011. Ankle Osteoarthritis – A Review of the Current State of Knowledge. European Musculoskeletal Review, 6(2), pp. 114-118.
Name: David Smith Email: firstname.lastname@example.org DTC Year: 3 Institution: Loughborough
Non-invasive Image Analysis as a Process Title: Analytical Tool (PAT) for Cell Based Therapy Manufacturing Author(s): David Smith, Rob Thomas Abstract: Conventional pharmaceutical and biologics production has begun to embrace the concept of Quality by Design (QbD) to reduce the risk associated with poorly developed processes. A major limitation on process development using QBD is the lack of non-invasive and label free measurements of process performance.
Therefore the aim of this work is to develop quantitative metrics derived from non-invasive image analysis that can be used to make process decisions that control quality within therapeutically relevant cell cultures.
Abstract Exploring the improvement of human cell Title: cryopreservation- benchmarking the gold standard Author(s): Tim Morris, Chris Hewitt, Karen Coopman
Future work is focused on the derivation of hMSCs from fresh bone marrow, defining a baseline thereof and repeating the previous work with this more therapeutically relevant cell line. Further, a design of experiments style procedure will be applied to cryopreservation to define more parameters for the development of a new process.
Coopman, K., 2011. Large-scale compatible
methods for the preservation of human embryonic stem cells: current perspectives. Biotechnology Progress, 27(6), p.1511-1521.
Keros, V. et al., 2005. Optimizing cryopreservation of human testicular tissue: comparison of protocols with glycerol, propanediol and dimethylsulphoxide as cryoprotectants. Human Reproduction, 20(6), p.1676-1687.
Zampolla, T. et al., 2009. Effect of methanol and Me2SO exposure on mitochondrial activity and distribution in stage III ovarian follicles of zebrafish (Danio rerio). Cryobiology, 59(2), p.188-194.
Name: Nicholas Wragg
Abstract Characterisation of human mesenchymal stem cells via Title: extracellular markers and cytokine factors Author(s): Alexander Chan, Karen Coopman, Chris Hewitt
Stuart I. Jenkins1, Divya M. Chari1 Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST5 5BG, UK email@example.com firstname.lastname@example.org Stuart Jenkins is an EPSRC Landscape Research Fellow affiliated with the DTC Both rate and extent of magnetic nanoparticle (MNP) uptake are celltype-dependent. For example, dramatic intercellular differences are observed between central nervous system (CNS) glial subclasses, with implications for MNP-based tissue engineering applications where mixed neural cell populations exist, such as in vivo. Here, a rat glial co-culture model has been developed to test whether the rapid, extensive uptake of MNPs by microglia (CNS immune cells) serves as an ‘extracellular barrier’ to nanoparticle uptake by other neural cell types.
The model offers unique advantages: (i) parallel derivation of all cells from a single primary source; (ii) a single cell culture medium (tested and developed for this system) for isolated- and co-cultures; (iii) stoichiometrically-defined cellular ratios, facilitating modelling of different CNS regions/disease states. Astrocytes and oligodendrocyte precursor cells (OPCs) show drastically reduced MNP uptake when co-cultured with microglia. This confirmation of the 'barrier hypothesis' highlights the need to consider the relative abundance of each cell type when using MNPs in vivo. This system can be used to test the effectiveness of MNPs designed to target/evade specific cell types, with ongoing studies assessing: (i) whether polyethylene glycol (PEG) coated ‘stealth’ MNPs evade microglia (with enhanced uptake by other neural cells); (ii) if MNP uptake is altered in the immunosuppressed CNS, where microglial activity may be inhibited.
Mechanotransduction in Multipotential Mesenchymal Stromal cells Lindsey Parker DTC program (year 2), Institute of Mechanical and Biological Engineering (iMBE), University of Leeds Supervisors: John Fisher MBE (iMBE), Daniel Thomas (iMBE) & Eileen Ingham (iMBE)
Mechanical stimuli have been shown to affect gene expression in a range of differentiated cell types. There have, however been limited studies of mechanotransduction in multipotential mesenchymal stromal cells (MSC), in particular in three dimensional culture.
1. To determine the optimal strain regimen for differentiation of hMSC towards a smooth muscle lineage
2. To establish the role of the cytoskeleton, ion channels and focal adhesions (FAs) in the strain-induced differentiation of hMSC
3. To dissect the roles of downstream signalling pathways in the strain-induced differentiation of hMSC
4. To determine the local strain experienced by cells during the strain-induced differentiation of hMSC
An acellular porcine pericardium scaffold will be used to support 3D culture of MSCs and the cells will be subject to cyclic tensile and biaxial strain (2-12%) in the Tencell and Biaxcell bioreactors. Optimal strain regimens for the differentiation of MSC towards a smooth muscle lineage will be selected for use in studies examining the mechanism of mechanotransduction in MSC.
To date studies have focussed on the preparation of the acellular pericardial scaffold. Pericardia (35) were subjected to an established decellularisation process in batches of 9 – 12, and validated using histology, DNA assays and cytotoxicity and sterility testing.
Characterisation of wear and wear debris within cervical TDR utilising Silicon Nitride Coatings under standard and adverse loading conditions.
Kinga Pasko, Dr. Joanne Tipper, Prof. Richard Hall, Prof. Anne Neville Institute of Medical and Biological Engineering, School of Mechanical Engineering University of Leeds, UK Cervical total disc replacement (CTDR) has been increasingly used as an alternative to fusion surgery in patients with pain or neurological symptoms in the cervical spine who do not respond to non-surgical treatment. However, current CTDRs are often associated with issues similar to those affecting other joint replacement devices, including excessive wear and wear particle-related inflammation. Currently, there is little known about the characteristics of wear debris produced by CTRD devices, and any potential adverse effects of the particles on tissues surrounding the spinal cord. Additionally, current materials and material combinations do not offer the required implant longevity and reliability. Recently a novel silicon nitride (SiN) coating has been shown to have favourable wear characteristics and to produce debris that resorb over time, thus reducing the risk of adverse biological responses to these particles. The project will investigate the characteristics of wear and debris produced by CTDR devices coated with SiN deposited utilising PVD-HIPIMS technology. Additionally, solubility and biological responses (cytotoxicity, inflammatory response) to the SiN particles will be studied. The novel SiN coating may offer more reliable CTDRs, and thereby improve the quality of life of patients, by reducing risk of failures and providing a longer lasting solution.
Mechanical Characterisation and Computational Modelling of Spinal Ligaments Ayesha Bint-E-Siddiq1, Ruth Wilcox1, Alison Jones1 Institute of Medical and Biological Engineering, University of Leeds, Leeds LS2 9JT The study will focus on an often overlooked aspect of the spinal motion segment: the spinal ligaments. These ligaments provide passive stability to spine and some studies have suggested that they play a major mechanical role within the physiological range of motion. However, the existing literature on the physical and mechanical properties of spinal ligaments span a large range and depending on these characteristics the resulting mechanical effects varies dramatically. The aim of this study is to characterise the ligamentous spinal structures and identify their importance in functional spinal unit models both experimentally and computationally. The experimental aspect will involve the use of advanced imaging (MRI, microCT) and mechanical testing facilities to characterise the morphology and mechanical properties of spinal ligaments. Furthermore, the computational aspect will involve specimenspecific modelling approach making use of the Finite element analysis packages to evaluate the mechanical role of these ligaments. The work will mark a step change from the current state-of-art where ligament properties and geometry are derived from widely varying data in literature.
The Fabrication and Characterisation of Nonwoven Fibrous Scaffolds with Novel Architectures for Craniofacial Tissue Engineering
Non-union bone defects commonly occur due to trauma and disease;
these defects can be extremely debilitating and when present within the skull can leave patients’ appearances altered. Globally, over 4 million operations are carried out requiring bone grafting each year1.
Autologous bone grafts are the current gold standard but up to 30% fail due to associated problems such as pain, parasthesia and donor site morbidity2. The use of tissue engineered bone substitute materials as scaffolds are gaining in popularity due to their reduced risk of disease transmission and their modifiable properties. This project’s focus is the fabrication of nonwoven fibrous scaffolds that promote full osseointegration within the native bone structure.
Various spinning technologies are being used to produce nonwoven collageneous fibrous meshes. In particular electrospinning and forcespinning, two fibrous manufacturing technologies that can produce biomimetic fibres at the nanoscale level and have the capabilities of being scaled up. A study is ongoing in which collagen is being spun with phosphate buffers and ethanol to improve biocompatibility. This drive to use more biocompatible substances is being continued across the entire fabrication process with novel crosslinking methods that have been proved to be less cytotoxic when compared with more traditional crosslinking methods being employed.
The long term aim of the project is to produce a nonwoven collagen scaffold with improved bone regeneration when compared with the current gold standard treatments for facial bone defects.
Name: Alan Weightman
Background Current clinical bladder augmentation materials have limitations [1,2,3].
Previously an acellular porcine bladder biomaterial was developed .
Inflation of the organ enabled complete decellularisation of the thickwalled tissue, but the process is incompatible with scalable manufacturing processes.
Aims The aim of this project is to develop a process for the decellularisation of porcine bladder which can be translated to commercial manufacture.
Experimental approach Initial studies focussed upon understanding the physical state of the bladder required to achieve successful removal of the cellular components during the wash process.
Bladders from 20-26 week old pigs were transported in transport medium to the laboratory within 2 hours of slaughter. Decellularisation was performed by distending the bladders using 500 ml of sequential buffers . Histological examination of the processed bladders showed the presence of cellular material. It was hypothesised that insufficient distension resulted in inadequate diffusion of the solutions into the bladder wall. Subsequent studies confirmed that the volume capacity of the bladders was substantially greater than 500ml.
Discussion/future work Studies will progress to repeat the decellularisation process at bladder volume capacity. Data on the deformation of bladders will determine the biaxial strain at volume capacity with a view to developing a device to hold bladder patches at the biaxial stress state of fully distended bladders during a manufacturing process.
References  Tanagho, E. & McAninch, J. (2004), Smith's General Urology, McGraw-Hill.