| Dr C K Chong |
| 3 |
A QUANTITATIVE ANALYSIS OF HEMODYNAMIC FORCES ON CELLULAR RESPONSE
Supervisor: Dr C K Chong |
| Haemodynamic (or biomechanical) forces have been suggested to play important roles in. arteriosclerosis, intimal thickening (IT), and restenosis related to stented arteries or surgical anastomosis. Certain flow features e.g. low mean shear stress, oscillating shear stress, abnormal temporal and spatial shear stress gradients, and high particle residence times, are found in the locations where early IT is greatest, suggesting a possible correlation between blood flow features and cellular responses, and failure of the endovascular device or surgical bypasses. This project aims to better understand this correlation through a quantitative analysis. The proposed project involves (i) the design, development, and characterization of an in-vitro cell culture-perfusion system capable for exposing viable cells cultured/co-cultured in well-defined geometries to precisely-controlled flow and pressure parameters, (ii) designing and performing parametric studies to understand the correlations and hence propose the mechanisms involved. Wherever appropriate, computational models may be employed to aid analysis. |
| 4 |
AN ANALYSIS CONTROLLED-DIFFERENTIATION AND PROTEINS SECRETION OF MSC IN BIOREACTOR
Supervisor: Dr C K Chong |
| Controlled-differentiation of mesenchymal stem cells (MSC) offers the prospect of regenerating living tissues/organs. This presents an area with exciting adventures and potential. To achieve this goal, there is a need to create the right environment appropriate for the studies of MSC activities and more importantly conducive to the controlled-differentiation of MSC. This project aims to develop a bioreactor to induce controlled-differentiation of, and proteins secretion by MSC, targeting the cardiovascular tissues. It involves (i) identification of the biomechanical factors and selection of appropriate matrix, (ii) design, set up and characterization of a bioreactor system capable of incorporating/reproducing these factors, (iii) perform MSC culture on selected matrices and execute parametric studies to understand the differentiation of, and proteins secretion by MSC and hence propose the mechanisms involved. Wherever appropriate, computational models may be employed to aid analysis. |
| 5 |
EFFECTS OF SCAFFOLD STRUCTURES ON MASS TRANSPORT AND REGERNERATIVE PROCESSES
Supervisor: Dr C K Chong |
| Scaffold plays an important role in tissue regenerative process which may take place either in vivo (with or without cell seeding) or in vitro (with cell seeding). This regenerative process involves cell attachment, proliferation, migration and extracellular matrix (ECM) deposition. To ensure that these events are taking place effectively, it is important that the cells are in their metabolically-active state and this requires efficient mass transfer. Studies have shown that the structural properties of scaffold could influence cellular events. However, their exact correlation and the mechanism involved are yet to be established. The proposed project aims to gain more insights on the effects of scaffold structure on mass transport and regenerative process and how tissue regeneration can be optimized. It involves (i) the design, development, and characterisation of scaffold perfusion/construct culture system, (ii) fabrication and characterization (e.g. pore size, porosity, interconnectivity) of stabilized porous scaffolds, (iii) measurement of mass transfer parameters (e.g. diffusivity, flow rate), (iv) culture of cell-seeded scaffold and assessment. |
| Professor J Harding |
| 6 |
SIMULATING THE GROWTH OF BIOMATERIALS
Supervisor: Professor J Harding |
| Minerals in biological systems (such as shells, teeth and bones) grow into complex shapes, often nothing like the shapes expected from conventional crystal chemistry. Somehow, organic molecules in the environment where the mineral grows are controlling this. It is likely that the mineral begins as a soft, hydrated, amorphous material and only later becomes a hard, crystalline materials. This project will use a range of simulation techniques to investigate how a variety of organic molecules can control the growth of carbonates and phosphates. This project is linked to collaborations with experimental groups both in the UK and elsewhere. Most of the codes required to do this have already been written, but there will be possibilities for people to develop programming skills if they so wish. |
| Dr J Haycock |
| 7 |
ENGINEERING OF PERIPHERAL NERVE
Supervisor: Dr J W Haycock |
| The human body has the potential to repair nerve tissue following trauma or injury. However repair is frequently not achieved or is incomplete because of lack of physical and chemical guidance between proximal and distal nerve terminals. The use of conduits offers a crude method for redirecting growth and early clinical trials show some promise. This project aims to advance conduit design by designing unaxial micro-channels that ultimately degrade. Channels will contain Schwann cells that are needed for the optimal provision of growth factors for aiding axon growth and myelin production. This project is highly multidisciplinary and encompasses bioreactor design, cell culture, biochemical detection, confocal microscopy imaging and biomaterials science. |
| 8 |
DRUG DELIVERY BY BIOACTIVE SURFACE ADHESION
Supervisor: Dr J W Haycock |
| This project is based on the use of potent synthetic calixarene-peptide compounds that can be used to treat biomaterial surfaces (or tissue engineered scaffolds) where inflammation is a major problem. An integrated one-stage method for reducing local tissue inflammation is expected to benefit patient health care and have socio-economic benefits. It will involve the design and use of novel analytical techniques in biochemistry / cell and molecular biology for the evaluation, design and synthesis of bioactive materials. Achieving this will therefore require an interdisciplinary approach spanning cell biology and synthetic chemistry / biomaterial science. An understanding on the use of calixarene-peptide chemistry will be expected to have commercial potential, as the proposed generic approach will be applicable to designing other biologically active peptides for many medical device / tissue engineering applications. This project will therefore be suitable for graduates with backgrounds in pharmacy, materials science, biology/biochemistry or chemistry. |
| 9 |
TISSUE ENGINEERED MODELS FOR DRUG AND COSMETIC SCREENING
Supervisor: Dr J W Haycock |
| Existing approaches that test compounds for irritation, toxicity or inflammation consist largely of very simple cellular tests or inappropriate animal models. There is therefore an increasing need to develop more relevant and accurate reporter systems of cellular stress for developing 3D tissue engineered models for toxicity testing. A European Council Directive (76/768/EEC) will enforce developing alternative tests for irritants and prohibit the use of animals for toxicological testing from 2009. This highlights that alternative methods must replace animals traditionally used for irritation, corrosivity and phototoxicity tests. Such alternative approaches include the use of reconstructed skin equivalents that match the properties of human skin as closely as possible. Using our engineered model of this tissue we will use genetically transfected reported constructs to detect the response of toxic agents in 3D. This will be an interdisciplinary project encompassing biomaterials, cell culture, molecular biology, biochemistry and confocal microscopy. |
| Professor S MacNeil |
| 10 |
ENDOTHELIAL CELL CULTURE ON ELECTROSPUN FIBRES
Supervisor: Professor S MacNeil |
| Very often in biomaterials one wants to produce a surface where endothelial cells will attach and grow well. This is quite challenging. Current data suggests that endothelial cells prefer nanofibrous scaffolds to microfibre scaffolds but this is far from clear. In this project the behaviour of freshly isolated endothelial cells (isolated from human skin) on a range of electrospun scaffolds of various fibre diameters will be examined to try to determine some real parameters of what it takes to make an endothelial cell happy. This project will involve cell culture and interaction of cells with electrospun fibres. |
| 11 |
INVESTIGATION OF THE USE OF BIODEGRADABLE SCAFFOLDS AS AN ALTERNATIVE TO THE HUMAN AMNION IN TREATMENT OF DISEASES OF THE CORNEA
Supervisor: Professor S MacNeil |
Currently when patients suffer diseases of the cornea they often end up receiving cultured epithelial cells transplanted to the cornea on human amniotic membrane. While this can work well, there are problems in the supply of the human amnion, in making sure that it is from screened donors via accredited tissue banks and therefore poses little or no risk to the patient and also problems in the processing of the amnion so that the results obtained are variable.
In this project, we propose to use biodegradable electrospun scaffolds composed of a 50:50 mix of PLLA to PGA as an alternative to the human amnion. Rabbit corneal epithelial cells and stromal cells will be cultured and placed on the biodegradable membrane. After a couple of days of culture the cells on the membrane will be transplanted to a rabbit organ culture model from which the cornea will have been removed and then these will be sutured in place . The survival of the cells and scaffold will then be investigated over the next 10 days. This project will involve working with electrospun materials produced by colleagues in Chemistry (Professor Tony Ryan and Dr Rob McKean), extensive cell culture of rabbit corneal cells and working with a 3D model of the cornea established using ex vivo rabbit corneas. This is a highly clinically relevant project in which the student will gain a great deal of experience of looking at the interface between cell biology and biomaterials and 3D models. |
| Dr S J Matcher |
| 12 |
OPTICAL MONITORING OF BONE REGENERATION
Supervisors: Dr S J Matcher and Dr G Reilly |
| The ability to regenerate bone tissue is a major goal of tissue engineering. Bone tissue is a complex biomaterial consisting of a collagen scaffold on which calcium phosphate crystals are deposited via the process of biomineralization. Current approaches to artificially recreating this material involve seeding polymer scaffolds with mesenchymal stem cells and then stimulating these cells to generate collagen matrix and deposit mineral. This process occurs in a specialised environmental chamber: the 'bioreactor'. Great interest currently surrounds the use of mechanical stimulation to promote collagen and hydroxyapatite formation and there is a recognised need for a tool that can monitor the biomineralization process in real-time and in a bioreactor. In previous work we have demonstrated that the degree to which bone tissue scatters light correlates with bone mineralization. We have also demonstrated that a novel technique, optical coherence tomography (OCT) can measure the light scattering of bone samples in a bioreactor and have related the OCT measurements to a "gold-standard" technique, quantitative x-ray computed tomography (qCT). Interestingly, we have found preliminary evidence that the changes in light scattering measured by OCT might be a more sensitive measurement of the mechanical strength of the bone than the qCT measurements. This raises the important questions a) how do the light scattering properties of bone relate to its microstructure and b) how does the microstructure influence the mechanical strength? This project will investigate the relationship between optical scattering, qCT densitometry, mechanical strength and tissue microstructure in a systematic way. Techniques to be employed include OCT, qCT, SEM and confocal Raman spectroscopy. |
| 13 |
OPTICAL MEASUREMENT OF CELLULAR RESPIRATION IN BIOENGINEERED TISSUES
Supervisors: Dr S Matcher and Professor S MacNeil |
| Tissue engineering currently lacks reliable, non-destructive and non-invasive tools to monitor the growth and viability of artificial tissues. Optical imaging and spectroscopy offer one technology that is ideally suited to fulfilling this requirement. This project will aim to use optical spectroscopy to monitor the viability of cells cultured in an artificial matrix via bioenergetic signals from respiratory chain enzymes. At the cellular level, fluorescence spectroscopy will be used to determine mitochrondrial redox potential from the nadh/fad fluorescencne ratio. On larger tissue volumes, optical reflectance spectroscopy will be used to determine the redox state of cytochrome-oxidase. The utility of these measurements in improving the quality of artificial skin, oral mucosa, cornea etc will be fully intvstigated using established tissue models. |
| 14 |
NANOPARTICLE CONTRAST AGENTS FOR OCT IMAGING OF EPITHELIAL CANCER
Supervisors: Dr G Reilly and Dr S Matcher |
| Optical coherence tomography (OCT) is a powerful new biomedical optical imaging modality. Within the last 10 years it has become established as the method of choice for imaging the retina of the eye but it also has great potential for the non-invasive detection of epithelial cancers. Although OCT an only probe the surface 1 mm of tissue, this is potentially enough to detect over 90 of new tumours at an early stage, if endoscopic techniques are used. The biggest problem at the moment however is that tumours do not display a strong enough contrast relative to normal tissues to allow reliable detection. This project aims to address this situation by combining state-of-the-art OCT imaging techniques such as molecular pump-probe spectroscopic OCT with recent innovations in polymeric nanovectors for the intracellular delivery of optical contrast agents. By combining expertise in both these fields we have the potential to realise a significant improvement in the diagnostic capabilities of OCT imaging. |
| Dr G Reilly |
| 15 |
COLLAGEN ORIENTATION IN TISSUE ENGINEERED SCAFFOLDS
Supervisors: Dr G Reilly and Dr S Matcher |
| In tissue engineering cells are grown in a scaffold in which they produce extracellular matrix. The hope is that these cell-seeded scaffolds could be implanted into the body to replace defective or damaged tissues. Many tissues, e.g. skin, tendon, bone and cartilage, contain highly orientated extracellular matrices in the body, but it is very difficult to create such organised structures in tissues formed outside the body. In this project we will compare different scaffold structures, made from synthetic and natural polymers to see which ones allow the best collagen alignment. The project will compare foam-like porous structures with fibrous structures created by electrospinning. We will also use mechanical stimulation to investigate how collagen aligns in relation to the direction of the applied load. Alignment will be investigated by Optical Coherence Tomography (OCT) and compared to results from confocal microscopy and small angle x-ray analysis. Fluorescent microscopy will be used to see which extracellular molecules help to guide the orientation. The project will be performed in collaboration with Professor Tony Ryan of the Chemistry Department and Sheila Mac Neil from Engineering Materials. This is a highly interdisciplinary project, involving materials science, chemistry, engineering and biological techniques. Students with a range of scientific backgrounds will be considered. |
| 16 |
USING TISSUE ENGINEERED BONE TO EXAMINE COLLAGEN AND MINERAL GROWTH AROUND METAL IMPLANTS
Supervisor: Dr G Reilly |
| There has recently been much interest in the use of tissue engineered structures to test procedures in vitro (outside the body) that are currently tested in vivo. For instance, tissue engineered bone, grown in scaffolds in a bioreactor environment, could be used to test how bone grows around an implant before using this type of implant clinically. This project will use cubes of tissue engineered bone, made by growing cells in 3D polymer scaffolds as a test site for implanting implants made from metals and other clinically utilised materials. The bone/implant construct will be mechanically loaded to simulate the in vivo environment. Bone growth around the implants will be imaged by microCT, confocal microscopy and histology. The results from the project will be compared with finite element simulations being performed at the University of Hull with our collaborator Michael Fagan. This project would best suit someone with a materials/ biomaterials/ engineering background but a student with a good biology background and an interest in bioengineering could also undertake this project. |
| Dr F Claeyssens |
| 120 |
DIRECT LASER WRITING OF VASCULATURE
Supervisor: Dr Frederik Claeyssens |
One of the most important issues problems that need to be solved for successfully tissue engineering of large and complex organs is the inclusion of vasculature in the scaffold to provide oxygen and nutrients to the growing tissue and carry away waste products.
In this project we will investigate building a synthetic analogue to these natural vascular networks via Direct Laser Write (DLW). With this revolutionary production technique, in which we use a short pulse-length (sub-nanosecond) Nd-YAG laser to produce 3D objects via two-photon polymerisation. This technique allows for the formation of tailor-made structures directly from a 3D computer model, via localised photopolymerization of materials. With this technique it is possible to construct micrometer-sized 3D features making this an ideal technique for integrating materials with biology.
We will direct write a proto-vasculature in biodegradable biocompatible polymers and use these tubes to seed a vascular network within a scaffold. This network will incorporate the appropriate growth factors to enhance vascularisation. The tissue engineering scaffold with proto-vascular network will be integrated in a bioreactor which will provide perfusion of the scaffold. The perfusion medium will be seeded with endothelial cells to build up a capillary network. We will specifically concentrate on vascularisation for skin tissue engineering in collaboration with Prof. S. MacNeil.
This interdisciplinary research project will provide the prospective PhD student with experience in polymer/biomaterials synthesis, laser-based production techniques, materials analysis techniques and cell culture. |
| 121 |
CONTROLLED 3D BIOMATERIALS MANUFACTURE
Supervisor: Dr Frederik Claeyssens |
This project has a two-fold aim, (i) production of three-dimensional (3D) objects in biocompatible materials (i.e. materials that do not have toxic or harmful effects to biological systems) and (ii) application of these structures in biology.
The building of biocompatible 3D structures will be achieved via microstereolithography (μSL), a laser based direct-write technique. This technique allows for the formation of tailor-made structures directly from a 3D computer model, via localised photopolymerization of materials. With this technique it is possible to construct micrometer-sized 3D features making this an ideal technique for integrating materials with biology.
Applications of this technology in tissue engineering will be investigated during this project, specifically for tissue engineering. The production of a living 3D tissue of its constituent cells starts with providing a 3D scaffold for cells to attach to and to grow in and this project will investigate the production of these ‘tissue scaffolds’. These scaffolds will be built from a biocompatible material and will give the initial rigidity to the engineered tissue, so that the cells can build up their own connective tissue or Extra Cellular Matrix (ECM). Once the ECM is built the engineered scaffold becomes redundant, so this project will concentrate on biodegradable polymers as scaffold material. We are particular interesting in producing scaffolds for neural tissue engineering.
This interdisciplinary research project will provide the prospective PhD student with experience in polymer/biomaterials synthesis, laser-based production techniques, materials analysis techniques and cell culture. |
| 122 |
LASER BIOPRINTING
Supervisor: Dr Frederik Claeyssens |
This project aims to build up a laser-based printing technique for biology. This printing technique utilises the Laser Induced Forward Transfer (LIFT) process to print biological molecules onto surfaces. This versatile technique is able to print solids, viscous liquid materials and powders. Furthermore, previous work has shown that biomolecules (proteins, DNA) and even entire cells can be printed without significant degradation or denaturation. This technique enables to print complex 2D micrometer patterns of biomolecules and cells, and the project will investigate biomolecule printing on biocompatible and biodegradable materials.
This technique will produce in a first iteration 2D patterned tissue sheets, and these will be at a later stage combined to attempt the layer-by-layer build up of 3D tissues. The sheets will be constructed from biodegradable materials, so these sheets will provide an initial structure for cells to grow in, while they build up their own extracellular matrix (ECM).
This interdisciplinary research project will provide the prospective PhD student with experience in polymer/biomaterials synthesis, laser-based production techniques, materials analysis techniques and cell culture. |
