Year of Award

2020

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Materials Science

Department or School/College

Department of Chemistry and Biochemistry

Committee Chair

Andrij Holian

Commitee Members

Armando McDonald, Nicholas R. Natale, Christopher Palmer, Aaron Thomas, Rob Walker

Keywords

drug delivery, coaxial electrospinning, nanoparticles, stimuli-responsive hydrogels, microgel particles, subcutaneous implantation

Subject Categories

Biology and Biomimetic Materials

Abstract

Electrospinning is the most widely studied technique of producing fibers. Delivery of nanoparticles and therapeutic agents from electrospun fibers have potential uses in various fields including drug delivery, filtration, and cosmetics. However, controlling the delivery rate remains the main challenge. In the current study, core-shell structure fibers were developed with zinc oxide nanoparticles applied in the shell composition to improve the pore structure (release pathway) and mechanical stability. Fine-tuned delivery rates were achieved via loading different sizes of silver nanoparticles (Ag NP) inside the fiber core. In vitro drug release assays showed fast, slow, and intermediate delivery rates of 20 nm Ag NP, 110 nm Ag NP, and a mix of the two Ag NP, respectively. In the next step, temperature-controlled delivery rates were achieved via loading thermoresponsive microgel particles of poly(n-isopropylacrylamide) in addition to Ag NP inside the fiber core. In vitro drug release assays showed a fast release of Ag NP above the transition temperature and a slow release below the transition temperature. Ball-milling of the hydrogel was developed as a versatile, simple, and high yield technique of producing microgel particles (microgels). In vitro antibacterial tests confirmed the efficacy of the fiber meshes for anti-infection applications. Subcutaneous implantation of fiber meshes in a mouse model confirmed the in vivo drug release performance of the fibers. Fiber meshes were had appropriate biocompatibility and mechanical stability. The thorough characterization, in vitro and in vivo analyses of the fiber meshes confirmed their potential for prolonged drug delivery applications.

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© Copyright 2020 Zahra Mahdieh