Self-inflating hydrogel tissue expanders have drawn great interest for generating new soft tissue in plastic and reconstructive surgeries. However, their over-rapid expansion rate can lead to tissue necrosis. Additional coatings or membranes can provide controlled swelling, but will be damaged upon crafting. This study is concerned with developing a novel inter-penetrating polymer network (IPN) tissue expander with controlled expansion and the ability to be crafted by surgeons as well. Firstly, VP/MMA-PLGA IPN has been prepared by crosslinking a secondary PLGA network in the presence of a primary VP/MMA network. The incorporation of PLGA effectively decreases the initial swelling rate and extends the swelling period. It is the only self-inflating tissue expander at present with controlled swelling and the ability to be crafted by surgeons. However, the equilibrium swelling ratio is sacrificed with increased PLGA weight fraction, which will limit the application of this IPN expander to surgeries that only need small tissue expansions, such as anophthalmia, eyelid, lip or nose reconstructions. Secondly, PLGA has been replaced with alternative secondary polymer networks, PLA and PCL to prepare IPN hydrogels. The swelling behaviour of VP/MMA-PLA IPN and VP/MMA-PCL semi-IPN is closely linked with the hydrophobicity and weight fraction of the secondary network, regardless of its glass transition temperature or crosslinking condition. At a similar weight fraction, the more hydrophobic the secondary network, the lower the initial swelling rate and the equilibrium swelling ratio, and the longer the swelling period. Thirdly, HEMA, VP/HEMA, and HEMA/SA bulk hydrogels have been prepared as alternative primary networks. Hydrogels show an increased swelling capacity with increased content of VP or SA, but at the expense of mechanical properties at the swollen state. Both HEMA and VP/HEMA show a low swelling, which might not be enough to induce tissue expansion. HEMA/SA shows superior swelling in distilled water but minimal swelling in non-polar solvents. Finally, the in vivo study of VP/MMA-PLGA IPN has been performed in a sheep model. The IPN hydrogels successfully generate tissue growth with the same quality as natural skin tissue and without any signs of serious inflammation or tissue necrosis. The rapid degradation of PLGA in vivo can cause the loss in mechanical integrity, leading to hydrogel collapsing under the restorative force of the skin. But this could be solved by tuning the ratio of lactide to glycolide in PLGA.

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Large burns necessitate skin cover. Skin grafts provide a simple solution but are limited in availability. Cultured keratinocytes provide epidermal cover but invariably fail unless grafted on dermis. Synthetic Dermal Equivalents (SDEs) are mostly collagen based and are dogged by poor take. This thesis concentrates on enhancing the angiogenic capability of SDEs to increase take. Aims To develop components for a "smart" pro-angiogenic matrix for reliable take. To explore and investigate clinical adjuncts, to increase graft angiogenesis. To evaluate angiogenic factors and extracellular matrix components for endothelial cell migration promotion to include in a potential skin equivalent. To explore the in-vitro angiogenic properties of SDEs and the role/effective regimes of Ultrasound and Topical Negative Pressure (TNP). Greatest growth factor stimulation was from TGFB. Influence of migration by angiogenic factors was minimal compared to fibrin. Basal invasion into collagen was low. Fibrin stimulated migration seven fold over that of collagen (pO.OT ANOVA). Fibrin subunits had equal effect to fibrin. Glycosaminoglycans, Fibronectin and Vitronectin addition increased migration over that of collagen. The addition of collagen to fibrin inhibited invasion. Ultrasound at an optimum energy of 0.8W/cm gave a 3 fold increase in migration over control conditions. This was equal to the addition of fibrin. Angiogenesis induced by TNP was optimum in Integra using an intermittent regime. This thesis has shown that collagen, the principal component of all SDEs fails to provide an optimal matrix for invasion of endothelial cells. We have found that the most favourable matrix constituents for endothelial cell migration are fibrin and fibrinogen with fibrin exerting a sevenfold increase in endothelial cell migration over collagen. It has also shown that TNP provides equal endothelial cell ingress to both US and fibrin, only when used intermittently with Integra.

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The use of live donors in renal transplantation is an area of rapidly expanding interest. This interest has been driven by the continuing fall in available cadaveric organs for transplantation. Live donor renal transplants accounting for twenty six percent of renal transplants in 2003, contrasting with an eight percent rate some ten years previously. Traditionally kidneys have been harvested from donors via a loin incision with partial resection of the tip of the twelfth rib, which placed a considerable burden on the donors in terms of post-operative pain, absence from work, and morbidity. A new minimally invasive laparoscopic technique was developed in 1995, which promised to lessen this burden placed upon the donor. Several non-randomised comparative studies have shown this new technique to hold promise in terms of less pain, and faster inpatient and outpatient recovery, with no apparent loss in quality of the graft harvested. Both pure laparoscopic and hand-assisted laparoscopic techniques are described, and two randomised trials have been published comparing a hand-assisted technique to the more traditional open technique. No study to date has compared a pure laparoscopic technique versus an open technique without resection of the twelfth rib. Our study showed a significantly shorter hospitalisation following the laparoscopic technique, associated with less pain on day one after the procedure. There were other favourable trends demonstrated with the laparoscopic technique, but larger trial numbers would be required to render these significant. No increase in donor morbidity, or difference in graft morphology, and graft function in the recipient was demonstrated. In conclusion, we have demonstrated that in the correct hands, laparoscopic live donor nephrectomy is a potentially superior donor procedure, with provision of equivalent quality allograft when compared to the traditional open procedure.