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Title: Injectable microgel systems : towards an injectable gel for heart tissue repair
Author: Thaiboonrod, Sineenat
ISNI:       0000 0004 5363 9940
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2014
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This thesis presents an investigation of cationic microgels based on poly(N-vinylformamide-co-glycidyl methacrylate) (PNVF-GMA) and poly(N-vinylformamide-co-2-(N-vinylformamido) ethyl ether) (PNVF-NVEE). They arestudied in the context of future heteroaggregated doubly crosslinked (DX) microgelsfor damaged heart tissue repair. The microgel particles were synthesised fromPNVF-GMA, which is also a water swellable microgel. The PNVF-GMA particleshad a core-shell structure in which PNVF provides the core and PGMA creates thecross-linked shell. The morphology of particles is that of a “cane-ball” like shape. There are interconnected ridges, and this unusual morphology can be controlled bythe weight fraction of GMA used during preparation. The hydrolysed PNVF-GMA(H-PNVF-GMA) particles were both positively and negatively charged. Moreover,charge patch aggregation occurred at low ionic strength. However, these microgelswere colloidally unstable after water rinsing due to shell fragmentation. PNVF microgel particles containing (N-Vinylformamido) ethyl ether (NVEE) as acrosslinking agent were also studied to avoid the fragmentation of the particles. Thismicrogel was hydrolysed in alkali conditions to provide poly(vinylamine-co-bis(ethyl vinylamine) ether) (PVAM-BEVAME), which contains primary aminegroups. It is proposed from the data presented that the content of hydrolysis was veryhigh and the particles were stable after hydrolysis owing to the stability of etherlinkage in NVEE. These microgels were able to swell upon decreasing pH. ThePVAM-BEVAME microgel with 9 mol% of BEVAME was then used to formdoubly crosslinked (DX) microgel. To form the inter-particles crosslinking, the vinylgroups were included by functionalisation using glycidyl methacrylate (GMA)monomer. The vinyl groups of neighbouring particles were linked together via freeradical reaction. The DX microgel formed under physiological temperature andshowed extensive porosity. These DX microgels had good mechanical propertiesconfirmed by high storage modulus (G’). Moreover, the precursor gels wereinjectable which is favourable for future biomaterial applications. The study providesa new family of cationic microgel that may be suitable for a future heteroaggregatedDX microgel for heart tissue repair.
Supervisor: Not available Sponsor: Royal Thai Government
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: microgel ; pH-responsive ; injectable gel ; cationic microgel