Hydrogen Bonded Multilayered Coatings for Biomedical Applications

Bizley, S. (2015) Hydrogen Bonded Multilayered Coatings for Biomedical Applications. PhD thesis, University of Reading.

Abstract/Summary

This thesis describes the formation and analysis of inter-polymer complexes formed from thelayer-by-layer deposition of polymers. The primary application of the complex was for the enteric release of antibiotics to the small intestine for eradication of local bacterial infections. The thesis initially reviews the formation of layered polymer complexes including different building strategies, relating this to potential applications. All the different polymers and related small molecules that can be utilised by this technique are discussed with specific reference to examples in drug delivery. This review is followed by the functionalization and characterisation of solid surfaces with a range of silane molecules, probing the deposition of poly(acrylic acid) and methyl cellulose. Freestanding multilayered polymer films are produced, optimising deposition conditions in relation to improved mechanical properties. The orientation of the polymer chains within the polymer film was manipulated via flowing of the polymer solutions across a detachable vinyl surface offering some changes in properties including strength, thickness and refractive index. Extensive analysis of poly(acrylic acid)-methyl cellulose complexes was carried out using Biacore recording the effect of solution pH and polymer molecular weight. This was followed by analysis of a range of polymer combinations showing the versatility and validity of the Biacore technique, this was supplemented by isothermal titration calorimetry analysis determining the rate and strength of polymer complexation. Gelatin matrixes loaded with suitable antibiotics were coated with the poly(acrylic acid)-methyl cellulose complex, an in vitro model analysed the release profile and showed a pH responsive release of drug in a simulated intestinal fluid after the coating provided protection from acid over a 30 minute period.