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oai:figshare.com:article/32805236 2026-10-01T16:17:14Z portal_1172 item_type_8 month_year_10_2026

Study of photoresponsive polymeric materials for antimicrobial nitric oxide delivery Tianchao Xie (24292574) PUREID: 669245206 Nitric oxide delivery Photoresponsive materials N-nitrosamines Polymer-based NO donors Silica-based NO donors Hydrogel coatings Hydrogel-based NO donors Light-triggered NO release Nitric oxide (NO), a reactive gaseous radical, plays key roles in therapeutics through vasodilation, neurotransmission, and immune regulation. However, its short half-life and high reactivity hinder stable storage and controlled delivery. Existing methods, such as gaseous inhalation or low-molecular-weight donors (e.g., nitroglycerin, NONOates, N-nitrosamines), suffer from non-specific release and toxicity risks. This thesis develops photoresponsive polymeric materials incorporating N-nitrosamine functionalities for stable NO storage and light-triggered release, optimising loading and kinetics by varying structural parameters.<br><br>Amine-functionalised divinylbenzene-vinylbenzyl chloride (DVB-VBC) copolymers, synthesised with adjustable DVB:VBC ratios and modified with ethylenediamine (EDA), diethylenetriamine (DETA), or p-phenylenediamine (PPD), achieved tunable NO loading (1.37 - 2.25 mmol g-1). Higher VBC content enhanced reactive sites, while straight-chain amines (EDA, DETA) outperformed aromatic PPD due to reduced steric hindrance. UV-triggered release (365 - 405 nm; 15 - 35 mW cm-2) followed pseudo-first-order kinetics, with straight-chain amines enabling sustained profiles and PPD yielding rapid bursts. Release rates scaled linearly with irradiance, peaking at 385 nm aligned with the n→π* transition.<br><br>Polyethyleneimine (PEI)-functionalised N-nitrosamine donors on MCM-41, clinoptilolite, and kaolinite exhibited NO loading (θmax = 0.184 - 0.642 mmol g-1) correlated with surface area (13.6 - 320 m2 g-1) and porosity. MCM-41 supported diffusion-limited, controlled release, whereas lower-porosity supports favoured faster surface-mediated kinetics. Optimal efficiency occurred at 385 nm, with half-lives of 1.83 - 362.90 min.<br><br>Calcium alginate hydrogels (CAH-1-3), functionalised with EDA and N-nitrosamine via oxidation, amination, and nitrosation, showed NO loading (θmax ≈ 0.03 - 0.13 mmol g-1) influenced by CaCl2 concentration (5 - 25 mg mL-1). DCAH-1-EDA-NO demonstrated superior loading and rapid release (k ≈ 0.987 min-1 at 365 nm), while DCAH-2-EDA-NO and DCAH-3-EDA-NO exhibited slower, surface-constrained profiles. <br><br><i>Thesis is embargoed until 31 July 2029.</i> 2026-10-01T16:17:14Z Text Thesis 10.17034/32805236.v1 https://figshare.com/articles/thesis/Study_of_photoresponsive_polymeric_materials_for_antimicrobial_nitric_oxide_delivery/32805236 All Rights Reserved Open Access after 2029-07-31