Degree Type

Dissertation

Date of Award

2008

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Victor Lin

Abstract

The research presented and discussed within this dissertation involves the development of mesoporous silica nanomaterials and magnetic nanoparticles based stimuli-responsive controlled-release delivery systems.;A superparamagnetic iron oxide nanoparticle-capped, MCM-41 type mesoporous silica nanorod-based controlled-release delivery system (Magnet-MSN) was synthesized. The stimuli-responsive release profiles of fluorescein-loaded Magnet-MSN delivery systems in the presence of external magnetic field was studied by using cell-produced antioxidants as triggers for releasing fluorescein molecules. The intracellular delivery efficiency of the Magnet-MSN system with human cervical cancer cells (HeLa) in vitro was demonstrated involving fluorescein molecules as model drug.;To take the advantage of the intracellular delivery capability of Magnet-MSN systems, a series of in vitro experiments demonstrating the loading and release of a DNA intercalating drug 9-aminoacridine was performed using Magnet-MSN by the action of reductant triggers. The in vivo application of Magnet-MSN with HeLa cells led to the enhanced cell growth inhibition effect. The cell growth inhibition was found to be unaffected by a strong external magnetic field.;A poly(N-isopropylacrylamide) coated mesoporous silica nanomaterials (PNiPAm-MSN) was demonstrated to load and release drug molecules using thermal stimuli as a trigger. Iron oxide (Fe3O4) nanoparticles were then attached to the surface of drug loaded PNiPAm-MSN to render the system magnetic (Mag-PNiPAm-MSN). Successful release of the loaded drug molecules was shown by placing Mag-PNiPAm-MSN under an alternating current based magnetic field. The mechanism of drug release was explained by the action of hyperthermia effect originating from the attached magnetic nanoparticles under the high frequency alternating magnetic field. The rate of drug release was also shown to be precisely controllable by controlling the parameters of the external magnetic field.

DOI

https://doi.org/10.31274/rtd-180813-16973

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Supratim Giri

Language

en

Proquest ID

AAI3337380

OCLC Number

313368512

ISBN

9780549923947

File Format

application/pdf

File Size

78 pages

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