Abstract

The thesis develops a rational framework for designing biopolymer-based matrices for hemostasis and active packaging by systematically linking mold geometry, polymer composition, and crosslinking chemistry to physicochemical and biological performance. In the first study, glutaraldehyde‑crosslinked gelatin hydrogels were cast as cubes, columns, and discs at fixed formulation and freeze‑drying conditions, with mold geometry scaled to maintain a constant volume-to-surface-area ratio across 25, 50, and 75 mL volumes. Despite identical composition and processing, the hydrogels exhibited markedly different behaviours: cubeshaped constructs showed the highest porosity, swelling capacity, and weight loss together with the lowest yield strength, while columnar constructs displayed the lowest swelling and highest compressive strength, with discs providing an intermediate response. These results demonstrate that mold geometry alone can be used to tune the balance between fluid uptake and mechanical robustness, identifying the cube as optimal for maximal swelling and the disc as a compact format with controlled deformation. Guided by these insights, the second study focused on disc-shaped chitosan/polyvinyl alcohol (Cs/PVA) hydrogels crosslinked with glycerol and citric acid and loaded with hydroxyapatite (HA) and ciprofloxacin (Cipro) as a multifunctional hemostatic system. The Cs/PVA‑HA‑Cipro discs exhibited high elasticity, low yield strength, and a swelling capacity of approximately 600%, together with significantly enhanced platelet aggregation compared with Cs/PVA discs without HA and Cipro, indicating more rapid clot formation. In addition, the Cs/PVA‑HA‑Cipro formulation provided strong antibacterial activity against representative Gram‑negative and Gram‑positive bacteria, confirming its potential as a passive hemostatic plug with integrated infection control. A key conclusion from this work is that PVA is essential to provide mechanical coherence to the hydrogel, while appropriate crosslinking is required to resist premature degradation. The final study translated these design principles to a non‑porous, thin geometry for active food packaging. Poly(vinyl alcohol) was converted to polyvinyl acetal (PVAcetal) and used as a film‑forming matrix incorporating Cs NPs loaded with tannic acid (TA). The resulting PVAcetal–CsNP–TA films exhibited enhanced tensile properties relative to neat PVAcetal, controlled TA release profiles, and pronounced antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), while effectively delaying spoilage in cherry tomato packing trials. Collectively, the three studies establish a coherent progression from geometry‑driven modulation of a model gelatin hydrogel, through the engineering of a disc‑shaped Cs/PVA hemostat, to the realization of a PVAcetal‑based active packaging film, offering a unified strategy for programming swelling, mechanics, and antimicrobial function in biopolymer matrices.

School

School of Sciences and Engineering

Department

Chemistry Department

Degree Name

MS in Chemistry

Graduation Date

Spring 6-14-2026

Submission Date

2-12-2026

First Advisor

Hassan M. E. Azzazy

Committee Member 1

Wael Mamdouh

Committee Member 2

Faten Farouk

Extent

138 p.

Document Type

Master's Thesis

Institutional Review Board (IRB) Approval

Not necessary for this item

Disclosure of AI Use

Thesis editing and/or reviewing

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Available for download on Friday, February 12, 2027

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