Matching Items (2)
Description
Mesoporous materials that possess large surface area, tunable pore size, and ordered structures are attractive features for many applications such as adsorption, protein separation, enzyme encapsulation and drug delivery as these materials can be tailored to host different guest molecules. Films provide a model system to understand how the pore orientation impacts the potential for loading and release of selectively sized molecules. This research work aims to develop structure-property relationships to understand how pore size, geometry, and surface hydrophobicity influence the loading and release of drug molecules. In this study, the pore size is systematically varied by incorporating pore-swelling agent of polystyrene oligomers (hPS) to soft templated mesoporous carbon films fabricated by cooperative assembly of poly(styrene-block-ethylene oxide) (SEO) with phenolic resin. To examine the impact of morphology, different compositions of amphiphilic triblock copolymer templates, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO), are used to form two-dimensional hexagonal and cubic mesostructures. Lastly, the carbonization temperature provides a handle to tune the hydrophobicity of the film. These mesoporous films are then utilized to understand the uptake and release of a model drug Mitoxantrone dihydrochloride from nanostructured materials. The largest pore size (6nm) mesoporous carbon based on SEO exhibits the largest uptake (3.5μg/cm2); this is attributed to presence of larger internal volume compared to the other two films. In terms of release, a controlled response is observed for all films with the highest release for the 2nm cubic film (1.45 μg/cm2) after 15 days, but this is only 56 % of the drug loaded. Additionally, the surface hydrophobicity impacts the fraction of drug release with a decrease from 78% to 43%, as the films become more hydrophobic when carbonized at higher temperatures. This work provides a model system to understand how pore morphology, size and chemistry influence the drug loading and release for potential implant applications.
ContributorsLabiano, Alpha (Author) / Vogt, Bryan (Thesis advisor) / Rege, Kaushal (Committee member) / Dai, Lenore (Committee member) / Potta, Thrimoorthy (Committee member) / Arizona State University (Publisher)
Created2011
Description
Ionizing radiation, such as gamma rays and X-rays, are becoming more widely used. These high-energy forms of electromagnetic radiation are present in nuclear energy, astrophysics, and the medical field. As more and more people have the opportunity to be exposed to ionizing radiation, the necessity for coming up with simple and quick methods of radiation detection is increasing. In this work, two systems were explored for their ability to simply detect ionizing radiation. Gold nanoparticles were formed via radiolysis of water in the presence of Elastin-like polypeptides (ELPs) and also in the presence of cationic polymers. Gold nanoparticle formation is an indicator of the presence of radiation. The system with ELP was split into two subsystems: those samples including isopropyl alcohol (IPA) and acetone, and those without IPA and acetone. The samples were exposed to certain radiation doses and gold nanoparticles were formed. Gold nanoparticle formation was deemed to have occurred when the sample changed color from light yellow to a red or purple color. Nanoparticle formation was also checked by absorbance measurements. In the cationic polymer system, gold nanoparticles were also formed after exposing the experimental system to certain radiation doses. Unique to the polymer system was the ability of some of the cationic polymers to form gold nanoparticles without the samples being irradiated. Future work to be done on this project is further characterization of the gold nanoparticles formed by both systems.
ContributorsWalker, Candace (Author) / Rege, Kaushal (Thesis advisor) / Chang, John (Committee member) / Kodibagkar, Vikram (Committee member) / Potta, Thrimoorthy (Committee member) / Arizona State University (Publisher)
Created2012