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Title: Development of new silicone-based biomaterials
Author: Robert-Nicoud, Ghislaine
ISNI:       0000 0004 2723 9310
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2012
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In the present thesis, we propose a modification of silicone surfaces using the controlled deposition of amphiphilic block copolymers from aqueous colloidal dispersions. The surface modifiers are based on poly(dimethylsiloxane) (PDMS) as the hydrophobic part, in order to allow a good compatibility with PDMS artefacts, and poly(glycerol monomethacrylate) (PGMMA) as the hydrophilic block, since this polymer has demonstrated good biocompatibility and low cell attachment. The hydroxyl groups present on PGMMA offer the possibility of further surface functionalization. We have demonstrated the convenience of preparing well-defined amphiphilic block copolymers of PDMS and PGMMA (which we refer to as Sil-GMMA polymers) via atom transfer radical polymerization using a protection/deprotection route (i.e. the silylation of GMMA alcohols groups). Depending on the ratio between hydrophobic and hydrophilic blocks, Sil-GMMA copolymers can self-assemble into micellar and other colloidal structures. Diffusion ordered nuclear magnetic resonance experiments have shown that those micelles did not interact with albumin, suggesting a “stealth” behaviour. Once a library of Sil-GMMA polymers with various block ratio was prepared, the adsorption of Sil-GMMA colloidal dispersions in water/ethanol on PDMS surfaces by simple physisorption was studied. As expected, high PDMS content favoured Sil-GMMA adsorption on silicone surfaces. The presence of our surface modifiers on silicone surfaces was confirmed by a decrease in water contact angle and spectroscopy techniques. We have shown that the surface coatings were stable upon storage in water. Additionally, fibrinogen adsorption was decreased by Sil-GMMA adsorption while albumin adsorption appeared to increase. The preparation of surfaces repellent to fibrinogen and interacting with a “passivating” protein such as albumin is promising. At the same time, this thesis also reports preliminary investigations on the use of enzymes in order to incorporate new functionality to GMMA containing polymers. Although enzymatic activity was observed when using PGMMA instead of glycerol with two different enzymes (glycerol kinase and glycerol dehydrogenase), PGMMA conversions were always low (< 2%).
Supervisor: Tirelli, Nicola. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Atom transfer radical polymerization ; Self-assembly ; Silicone surface modification ; Protein adsorption