Date of Award

5-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

School of Materials Science and Engineering

Committee Member

Dr. Stephen H. Foulger, Committee Chair

Committee Member

Dr. Konstantin Kornev

Committee Member

Dr. Igor Luzinov

Committee Member

Dr. Thompson Mefford

Abstract

Nanoparticle based drug delivery offers an advantage over free drug deliv-ery as it allows the manufacturer to introduce various control mechanisms either for targeted delivery or for the controlled release profile of the drug. Systems ca-pable to encapsulate different active molecules, ranging from dyes to drugs, gained a lot of attention in recent years. It was shown that it is possible to create a pro-grammable device that can serve multiple functions ranging from enhanced imag-ing techniques to cancer treatment along with extended drug delivery applications. Therefore methods for fabrication and characterization of the devices that can be used in the medical field is in high demand. Proposed is a device build around propargyl acrylate nanoparticle along with a set of methods to fully characterize the final nanocomposite composition. The release rate of the active molecules from the proposed nanocomposite is compared to the composition of the device. The ability to program the release rate and set a burst release temperature for the de-vice is essential for future advances in drug delivery application. Förster Resonance Energy Transfer (FRET) was used to investigate the changes in the surface configuration. To do this, pair of dyes with good spectral overlap was attached to the propargyl acrylate core. The donor dye was immobilized on the surface of the core, while the acceptor dye was attached to the free end of the poloxamer chain. This setup allowed the acceptor dye to have a certain degree of mobility. Based on the changes in the photo-luminescence spectra and applying the FRET theory distance between the dyes was correlated to the temperature of the environment. A possible mechanism of the surface configuration changes with temperature was suggested based on the obtained results. The ability of propargyl acrylate - poloxamer complex to capture, retain and release when triggered small molecules is investigated. Often there is a need to protect or deactivate an active molecule before it reaches its target organ or tissue to prevent development of side-effects during treatment. Additionally, such a sys-tem can be used for waste water treatment applications to remove toxic organic contamination. The ability of the particles to trap and then release upon heating is advantageous compared to the systems that are capable of only trapping because it can be reused and serve the purpose of waste concentration to promote recycling of otherwise wasted materials. Proposed is a scheme of synthesis and characterization of the carrier based on the propargyl acrylate nanoparticles coated with poloxamer copolymer. Carrier stability is greatly enhanced, compared to similar systems found in the literature. Advantage comes from the formation of a covalent bond between the core and the shell, ensuring that no changes of the nano-carrier composition can happen during its lifespan. This study shows the importance of the precise control over the graft-ing density of the poloxamer on the surface of propargyl acrylate nanoparticle. The ability to select various sizes of the nanoparticles and the selection of commercially available poloxamer copolymers provide the possibility to fine tune properties of the final carrier for the required task. The retention and release effectiveness was correlated to the nano-carriers composition and was shown on the example of Rho-damine B dye. The discovered principle of surface configuration changes during FRET section of this study helped with determination of the release mechanism.

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