Chronic wounds are a rapidly growing burden to patients and healthcare systems globally. The rising incidence of both obesity and diabetes worldwide, coupled with an aging population, are contributors to predictions that a greater number of patients will exhibit chronic wounds in the future. It has been shown that bacteria in wounds form persistent biofilms. Successful wound management calls for rapid, accurate diagnosis to control infections, as well as minimizing disruption to the wound site. Historically, clinical identification of infection at a wound site has relied on swabbing and culturing methods, and in recent years progress has been made in using electrochemical biosensors for the rapid detection of microorganisms. This study explores the detection of infections using impedance spectroscopy to monitor bacteria. Initial electrochemical impedance spectroscopy experiments using label-less carbon screen printed electrodes were conducted to characterise the impedance signatures of Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis. These bacteria, which are commonly found in chronic wound infections, were cultured in both rich laboratory media and simulated wound fluid. In the final part of the study a wound bed model was produced that simulated the environment representative of a wound infection including two dressing types, one honey-based and one silicone. Experiments were performed to assess the effectiveness of the impedance detection technique for chronic wound infections using this model. Differences in impedance characteristics were seen across bacterial strains in laboratory media and simulated wound fluid. The greatest changes were seen in P. aeruginosa, with smaller impedance signatures identified for S. aurues. Signatures were also observed for E. faecalis with significant differences seen in some regions of the impedance spectrum. Additionally, it was found that a honey-based dressing resulted in lower cell density of P. aeruginosa colonies after 72 hours and that prominent features in the phase component of impedance were present. Findings from this study support the possibility that impedance spectroscopy could be used for the identification of chronic wound bacteria in a future point of care device.

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The synthesis of amphiphilic hyperbranched glycopolydendrons bearing multivalent surface functionalities has yielded materials with potential nanomedical drug-delivery applications that may also be capable of actively targeting disease sites. The development of the hydrophilic surface functionalities (based on PEG, galactose and mannose moieties) and hydrophobic core functionalities (based on poly(n-butyl methacrylate)) are presented. Despite methanol (MeOH) being widely regarded as an antisolvent for p(nBuMA), Cu-catalysed ATRP of nBuMA has been performed utilising anhydrous MeOH as the reaction solvent. Successful polymerisation was achieved at 60 °C and 25 °C using ethyl 2-bromoisobutyrate as the initiator, yielding well-defined polymers with high molecular weights (up to Mn = 75 880 g mol-1) and low dispersities (as low as D = 1.02). The effect of monomer co-solvency was investigated by determining the cloud point behaviour (upper critical solution temperature) of p(nBuMA) within the methanolic environment, and the effect of the ligand on the control of the polymerisation was also investigated. Successful polymerisation was also extended to RAFT, yielding low dispersity polymers that were analogous to those obtained by ATRP. The methanolic polymerisation by Cu-catalysed ATRP was utilised to exploit the hydrophobic nature of p(nBuMA) as the core functionality of amphiphilic branched copolymer nanoparticles bearing PEG surface functionalities. The nanoparticles were prepared via a rapid nanoprecipitation approach, however, their small hydrodynamic diameters (Dn = 17 nm-27 nm) suggested nanoparticle formation by a solvent-switch rather than a nucleation/growth mechanism that is normally associated with this technique. Dendritic ATRP initiators bearing multivalent protected galactose functionalities, also varying in generation number, were obtained by aza-Michael-type additions and used within the branched methanolic ATRP of nBuMA. Deprotection of the isopropylidene protecting groups was achieved under acidic reaction conditions using para-toluene sulfonic acid monohydrate; nanoprecipitation of the resulting galactosylated hypglycopolydendrons yielded charge-stabilised nanoparticles with Dz = 43-46 nm and highly negative zeta potentials. Comparisons to their protected equivalents were made.

Research findings that have global impact need to be disseminated fast worldwide. A systematic review of dissemination methods found a small number of studies whose study quality was poor and which did not provide strong evidence. On-line videos have become one of the major information sharing methods. In a cross-sectional study of on-line videos, emotional content appeared to be associated with high view counts. However, the confidence interval was broad and there was a chance of confounding. Therefore, I examined the effectiveness of emotional content in an on-line video on the extent to which the video was shared. Methods I conducted a two arm randomised controlled trial. I created two videos one of which was more emotional. Outcome was video sharing. Participants were researchers and health care professionals in midwifery, obstetrics and gynaecology. An independent statistician generated a random allocation sequence using a computer programme (1:1 allocation). I sent an invitation e-mail with a link to the video to participants and asked them to watch the video and share it if they found it helpful. The data were collected for 14 days after the e-mail was sent. The person who assessed the outcome and analysed data was masked to intervention allocation. Results 8353 participants, 4178 in the intervention group and 4175 in the control group, were included. 221 participants (5.3%) watched the intervention video and 215 participants (5.2%) watched the control video. Of those who were randomised to the intervention video, 44 (1.1%) participants shared it and 37 (0.9%) of the participants randomised to the control video shared it (RR 1.2 [95%CI 0.8 to 1.8], p=0.44). Conclusion The results were imprecise as the number of outcome events was low. The results, albeit imprecise, showed that there was no strong evidence for the effectiveness of emotional content on on-line video sharing.

This thesis presents research on a novel method of microfabrication of titanium (Ti) biomedical devices. The aim of the work was to develop a commercial process to fabricate Ti in a more environmentally friendly manner than current chemical etching techniques. The emphasis was placed on electrolytic etching, which enables the replacement of hazardous hydrofluoric acid-based etchants that are used by necessity when using Photochemical Machining (PCM) to produce intricate features in sheet Ti on a mass scale. Titanium is inherently difficult to etch (it is designed for its corrosion-resistant attributes) and as a result, Hydrofluoric acid (HF) is used in combination with a strong and durable mask to achieve selective etching. The use of HF introduces serious health and safety implications for those working with the process. The new technique introduces the use of a “sandwich structure”, comprising anode/insulator/cathode, directly in contact with each other and placed in an electrolytic etching cell. In this technique the same photolithography process is utilised to achieve selective etching on a metal substrate as in the PCM process. However, for the electrolytic etching stage, the inter- electrode gap (IEG) is reduced significantly from a few centimetres, as usually applied in electrochemical processes, to 4 μm. The intention behind this was to improve the current distribution experienced at the anode (Ti) during subsequent electrolytic etching. The sandwich structure was developed by deposition of a photoresist S1818 and Copper (Cu) on top of Ti. Firstly, a manual sanding of the substrate was applied in order to eliminate the oxide layers which could strongly affect a final electrolytic etching. The soft- and hard-bake stages involved in the processing of the S1818 resist were optimised to produce a stress-free Ti/S1818/Cu/S1818 structure. Ultimately a pattern would be imparted onto the S1818/Cu/S1818 that would ultimately be imparted through to the Ti layer during the last stage, electrolytic etching. In order to achieve this, a Cu electroless deposition was developed as a technique to obtain a conductive film which would act as a cathode during the electrolytic etching of the target, Ti layer. The results of the electrolytic etching of the Ti sandwich structure revealed flat-base profiles of half-etched (“half-etch” is the term used to signify an etch that does not penetrate completely through the thickness of the metal sheet) micro-holes in the Ti layer. The problem of delamination of the electroless Cu, in 10 % w/v HCl electrolyte used as an etchant, was solved by electroplating a 12 μm layer of Cu on top of the 60 nm Cu electroless deposited film. Using this technique, micro-features were achieved in Ti. The half-etched micro-holes were characterised to have an overall spherical shape corresponding to the imaged pattern and a preferred flat-base profiles (typically a raised land of material arises in conventional electrolytic etching). A series of parameters were tested in order to control the process of electrolytic etching through the Ti sandwich structure by measuring etch rate, surface roughness of the etched pattern and the etch factor. The applied current densities (CD) of 10, 15, 20, and 25 A/cm2 showed proportional dissolution to the applied current. Electrolytic etching with a CD of 20 A/cm2 demonstrated a high etch rate of 40 μm/min. and a relatively low Ra of 2.8 μm, therefore, it was utilised in further experimental work. The highest etch rate of 50 μm/min. and an improved distribution of half-etched micro-holes was achieved by the introduction of 4 crocodile connectors (2 per electrode) and mechanically stirring of the electrolyte (800 rpm) while performing the electrolytic etching. The maximum etch depth of 143.9 μm was produced in Ti when the electrolytic etching was performed at the same conditions for 3 minutes. The incorporation of ultrasonic agitation to the electrolytic etching and an electrolyte temperature of 130 C resulted in a decrease of the surface roughness of the etched micro-holes to 0.5 μm. The results of the Ti sandwich structure electrolytic etching proved the concept of minimising the IEG in order to obtain a uniform Ti dissolution on a feature scale, improved control of the electrolytic dissolution over the whole area of the sample with utilisation of the lower hazard etchant at the same time.

The conventional colonoscopy is a common procedure used to access the colon. Despite it being considered the Gold Standard procedure for colorectal cancer diagnosis and treatment, it has a number of major drawbacks, including high patient discomfort, infrequent but serious complications and high skill required to perform the procedure. There are a number of potential alternatives to the conventional colonoscopy, from augmenting the colonoscope to using Computed Tomography Colonography (CTC) - a completely non-invasive method. However, a truly effective, all-round alternative has yet to be found. This thesis explores the design and development of a novel solution: a fully mobile colonoscopy robot called “RollerBall”. Unlike current passive diagnostic capsules, such as PillCam, this device uses wheels at the end of adjustable arms to provide locomotion through the colon, while providing a stable platform for the use of diagnostic and therapeutic tools. The work begins by reviewing relevant literature to better understand the problem and potential solutions. RollerBall is then introduced and its design described in detail. A robust prototype was then successfully fabricated using a 3D printing technique and its performance assessed in a series of benchtop experiments. These showed that the mechanisms functioned as intended and encouraged the further development of the concept. Next, the fundamental requirement of gaining traction on the colon was shown to be possible using hexagonal shaped, macro-scale tread patterns. A friction coefficient ranging between 0.29 and 0.55 was achieved with little trauma to the tissue substrate. The electronics hardware and control were then developed and evaluated in a series of tests in silicone tubes. An open-loop strategy was first used to establish the control algorithm to map the user inputs to motor outputs (wheel speeds). These tests showed the efficacy of the locomotion technique and the control algorithm used, but they highlighted the need for autonomy. To address this, feedback was included to automate the adjusting of the arm angle and amount of force applied by the device; a forward facing camera was also used to automate the orientation control by tracking a user-defined target. Force and orientation control were then combined to show that semi-autonomous control was possible and as a result, it was concluded that clinical use may be feasible in future developments.

For patients with end-stage bladder disease for which other treatment options have failed, the patient is treated surgically with either urinary diversion or bladder augmentation. Enterocystoplasty is the most common of these options, and it involves augmenting the bladder using a section of the patient's own intestine. However, there are several problems associated with the use of intestine for augmenting the bladder, and therefore an alternative augmentation material may be of benefit to patients. Numerous approaches have been used to develop tissue-engineered scaffolds capable of successfully augmenting bladders. Some of these approaches have involved the use of acellular tissue-derived materials, whereby the tissues are decellularised in order to remove immunogenic material and therefore prevent an immune reaction when transplanted allogeneically or xenogeneically. Decellularisation protocols typically involve a variety of chemical and physical processes which remove cells and other immunogenic material from the tissues. A protocol was previously developed to decellularise full-thickness porcine bladders. This material may have utility in bladder augmentation. The process involved distending the bladders with, and placing them in, a series of solutions. It was demonstrated that distending the whole organs was a necessary step in the decellularisation process. It was thought that this procedure applied biaxial strain to the wall of the tissue and reduced its thickness sufficiently for the solutions to penetrate the entire wall of the tissue. However, the method of distending whole bladders was not compatible with a scalable manufacturing process, and therefore the biomaterial was not able to be developed further. The overall aim of this project was to develop a novel method of manipulating bladder tissue which would enable bladder tissue to be decellularised in a way which would be compatible with a commercial manufacturing process. The original bladder decellularisation process used 500 ml of solutions to distend bladders. Preliminary experiments demonstrated that this volume was not always adequate to decellularise larger bladders. Filling experiments were performed to find relationships between bladder size and bladder capacity. A relationship between bladder capacity and bladder width*length was found to have a high correlation. Bladders were decellularised when filled to capacities calculated using the relationship. No signs of cellular material were observed in histological sections of these bladders, and DNA quantification indicated a removal of more than 99% of the DNA relative to native tissue. In order to determine the state of mechanical deformation of bladders during decellularisation, markers were placed on the surface of twelve bladders which were immersed in isotonic solution and slowly filled. Images taken of the bladders and markers during filling were used to calculate the strain of the tissues during the tests. The previously found relationships for bladder capacity were used to calculate the capacity of these bladders. The stress, strain and thickness of the bladders were calculated at the point the bladders were filled to their respective capacities. These strains were invariant with bladder capacity, and were equal to 2.0 and 1.4 in the circumferential and longitudinal directions respectively. Applying these strains to three bladders during decellularisation appeared to result in a complete removal of cellular material. It was thought that applying the required strains to bladder tissue deformed in a flat sheet configuration would be compatible with a manufacturing process. In order to apply biaxial strain to this highly compliant material, it was recognised that it would be appropriate to deform it using discrete points, placed along the edges of the tissue. The stretching of flat sheets of bladder using this method was modelled using finite element modelling to find an optimal stretching regime. The models demonstrated that deforming the tissue using five discrete points along each edge of the material would be adequate to ensure that the required strains would be applied to the tissue for decellularisation to occur. So that flat sheets of bladder could be decellularised, a piece of equipment was designed to hold pieces of bladder in the state of deformation which was previously modelled. The equipment took the form of a 3D-printed frame. A procedure was developed to stretch bladder tissue onto the frame. To test the hypothesis that bladder tissue could be decellularised in a flat sheet configuration, six bladders were stretched onto the frames and subject to the decellularisation process. Histological sections taken from decellularised bladder samples demonstrated a complete removal of cellular material, and a DNA extraction and quantification assay demonstrated that 99% of the DNA had been removed relative to the native controls. Bladders decellularised using the original process were transported in transport medium and processed within 4 h of bladder collection. A manufacturing process would require the tissue to be stored before processing. It was also recognised that it may not be necessary to transport bladders---which are destined for decellularisation---in transport medium, which was developed in order to maintain viable urothelial cells. To test the effects of freezing and transportation without transport medium, bladders were collected from the abattoir, transported without transport medium and subject to either one (six bladders) or two (six bladders) freeze-thaw cycles. Twelve fresh bladders were transported with transport medium. Bladders were immersed in solution and mechanically tested by distension, and their stress--strain curves calculated. There was no statistical difference between the toe region modulus and the transition stress of fresh, once-frozen and twice frozen bladders. There was a small but significant increase in the linear region modulus and transition stress of fresh bladders compared to the once- and twice-frozen bladders. No significant differences were found between once-frozen and twice-frozen bladders. To determine the effect of this revised transportation regime on bladder decellularisation, six bladders were transported without transport medium, subject to two freeze-thaw cycles and subject to the decellularisation process. Samples taken from these bladders for histological analysis and DNA quantification exhibited a complete removal of cellular material. In conclusion, this study demonstrated that applying suitable strains to flat sheets of bladder tissue was a viable method of deforming bladder tissue in order for it to be decellularised. Freezing the tissue up to two times before decellularisation resulted in some small but significant changes to the mechanical properties of the tissue, but did not affect the efficacy of the decellularisation process. It therefore may now be feasible to commercially produce decellularised full-thickness porcine bladder tissue.

Polymeric materials are excellent candidates for use as biomaterials. They are often employed as drug carriers to provide protection to encapsulated therapeutic molecules against premature metabolism, inactivation and clearance, and to reduce drug leakage and burst release, in vivo. Although significant progress in the medical sector has been registered, challenges still abound for the delivery of therapeutics. As such, the development of requisite nanocarriers and improvement of existing ones is crucial. NCA ROP and OCA ROP provide an alternative to solid phase peptide synthesis for the syntheses of polymeric biomaterials that have targeted applicability in drug delivery, in pharmaceuticals and in tissue engineering. This thesis demonstrates the use of controlled NCA ROPs and OCA ROPs to generate a range of novel poly(amino acid)s, poly(ester)s and hybrid materials through novel combinations of both techniques. Innovative routes to contemporary biomaterials that are presented include; employing a model therapeutic molecule, dopamine, to initiate NCA ROP, to yield amphiphilic dopamine-(peptide)-(peptoid) conjugates that self-assembled into biodegradable particles. Steglich esterification being used to graft alkyl groups from the OH-side groups of an oligo(L-serine) to yield a polymer capable of immobilising large quantities of edible vegetable oil, thus forming biodegradable organogels. NCA ROP initiated from a PEG star polymer that resulted in the generation of star-shaped hybrid polymers, which upon modification by thiol-ene click crosslinking, yielded polymers capable of forming disulphide-crosslinked hydrogels. Employing glucosamine to initiate sequential NCA ROP and OCA ROP reactions, to generate amphiphilic polymers that self-aggregated into monodisperse, glucose-presenting NPs. Oligo(L-serine), which was created by NCA ROP, being used to initiate the ROP of Phe OCA, yielding graft copolymers which self-aggregated into NPs that could be used for the controlled release of doxorubicin. The synthesis of diblock homopoly(ester)s, which could be used for the controlled release of hydrophobic chemotherapeutics, by the sequential ROP of Phe OCA and Glu(Bz) OCA, Phe OCA and Lys(Cbz) OCA, and Glu(Bz) OCA and Lys(Cbz) OCA. Collaborative initiatives led to the creation of prospective poly(amino acid)-metal-based anticancer therapeutics. In vitro biological studies and payload release studies were conducted on the materials created, to demonstrate their suitability as biomaterials. Proteolytic enzymes were used to trigger the degradation of poly(amino acid)-based materials, reduced environmental pH conditions were used to trigger the hydrolysis of poly(ester)-based materials and reductive environments were used to trigger the dissociation of disulfide-crosslinked hydrogels.

Respiratory motion a ects a wide range of techniques in the eld of medical image acquisition and analysis. In image-guided interventions it may cause misalignment of static road maps with the patient's anatomy. In imaging such as magnetic resonance (MR) imaging or positron emission tomography (PET) it may cause the images to appear blurred which may impede disease diagnosis and staging. Manifold learning is a powerful tool for the non-linear dimensionality reduction of imaging data, which can be used to uncover the data's dominating sources of motion. By aligning low-dimensional embeddings of multiple datasets, which vary due to the same motion, in a joint low-dimensional space accurate correspondences between the datasets can be established. In the first part of this thesis, manifold alignment is investigated for the robust reconstruction of high-resolution 4D (3D+time) MR imaging sequences of respiratory motion from sequentially acquired coronal 2D MR slices. In particular, a novel groupwise manifold alignment scheme is presented which outperforms two current state-of-the-art reconstruction techniques. From such 4D MR images very accurate motion estimates are derived, which, in turn, are used to correct for motion in simulated PET-MRI data. In the second part of this thesis, a patient-specific respiratory motion model presented based on groupwise manifold alignment. Such a motion model can be used to correct for 3D organ motion during an image-guided intervention where only 2D images are available. It is shown that the aligned low-dimensional representations obtained using manifold alignment may be viewed directly as a surrogate-driven motion model. By updating this low-dimensional manifold with points obtained from new 2D imaging data, the model can automatically adapt to previously unseen breathing patterns. Lastly, in the third part of this thesis, a novel manifold alignment method is outlined which does not require any of the datasets to be comparable in the image space. To this end a novel similarity kernel is proposed which allows comparison of visually distinct datasets by analysing their internal graph structure using a random walk approach. This allows to embed all data simultaneously in one step rather than in groups. It is shown that improved 4D MR reconstruction from multiple sagittal 2D MR slices can be achieved using this approach. Furthermore, the method is demonstrated on the time-resolved compounding of multiple 3D ultrasound views of the same organ.

INTRODUCTION: Extracorporeal Membrane Oxygenation (ECMO) causes coagulation and inflammation. Also pump tubing can rupture. Therefore new tubing is needed. AIMS: To compare mechanical properties and biocompatability of two potential ECMO tubings (LVA and SRT) with Tygon (current tubing). To develop a novel porcine veno-venous ECMO model. To review ECMO results at Glenfield Hospital. METHODS:. I) Mechanical: Durability; roller pump and test rig. Wear; electron microscopy. Spallation; laser diode particle counter. II) In-Vivo Biocompatability: 5 pigs for each material, 48 hours veno-venous perfusion, samples: Blood count, blood gases, Prothrombin, Thrombin and Activated Partial Thromboplastin times, Lactoferrin, C3adesarg and Thromboxane B2. Lung neutrophil immunohistochemistry, histology and lung water. III) In-Vitro Biocompatability: a) 5 circuits of each material recirculated for 6 hours, human blood. Samples as above plus fibrinogen, C5b-9 instead of C3adesarg. b) I125Fibrinogen uptake with and without albumin washing. IV) Clinical Review: Retrospective. RESULTS:;I) Mechanical: Tygon was unpredictable, but better than LVA and SRT. II) In-Vivo Biocompatability: The porcine model was successfully established. The only significant difference between groups was higher haemolysis with Tygon compared to SRT. Animals developed "ARDS" and thrombocytopenia. III) In-Vitro Biocompatability: a) SRT and LVA, increased coagulation. LVA increased haemolysis. b) Untreated Tygon, lower fibrinogen uptake, no differences after albumin. IV) Clinical Review: (n) and % survival: Respiratory; Adult (99) 63%, Paediatric (81) 77%, Neonatal (134) 75%. Cardiac; Adult (8) 38%, and Paediatric (28) 61%. Results for the first 50 adult respiratory patients: mean PaO2/FIO2. 65 36.9 mmHg, mean Murray score 3.4 0.5 and 66% survival. Compared to historical controls (55.6% & 42% survival) p=0.036 & p=0.0006. CONCLUSIONS: Neither SRT nor LVA are mechanically adequate for ECMO. SRT and LVA are less biocompatable than Tygon, causing more coagulation and haemolysis. The porcine model was technically successful but needs larger numbers to discriminate between materials.