Matching Items (6)
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- All Subjects: Nanoparticles
- Creators: Mu, Bin
- Creators: Vernon, Brent
- Status: Published
Description
Gold nanoparticles have emerged as promising nanomaterials for biosensing, imaging, photothermal treatment and therapeutic delivery for several diseases, including cancer. We have generated poly(amino ether)-functionalized gold nanorods (PAE-GNRs) using a layer-by-layer deposition approach. Sub-toxic concentrations of PAE-GNRs were employed to deliver plasmid DNA to prostate cancer cells in vitro. PAE-GNRs generated using 1,4C-1,4Bis, a cationic polymer from our laboratory demonstrated significantly higher transgene expression and exhibited lower cytotoxicities when compared to similar assemblies generated using 25 kDa poly(ethylene imine) (PEI25k-GNRs), a current standard for polymer-mediated gene delivery. Additionally, sub-toxic concentrations of 1,4C-1,4Bis-GNR nanoassemblies were employed to deliver expression vectors that express shRNA ('shRNA plasmid') against firefly luciferase gene in order to knock down expression of the protein constitutively expressed in prostate cancer cells. The roles of poly(amino ether) chemistry and zeta-potential in determining transgene expression efficacies of PAE-GNR assemblies were investigated. The theranostic potential of 1,4C-1,4Bis-GNR nanoassemblies was demonstrated using live cell two-photon induced luminescence bioimaging. The PAE class of polymers was also investigated for the one pot synthesis of both gold and silver nanoparticles using a small library poly(amino ethers) derived from linear-like polyamines. Efficient nanoparticle synthesis dependent on concentration of polymers as well as polymer chemical composition is demonstrated. Additionally, the application of poly(amino ether)-gold nanoparticles for transgene delivery is demonstrated in 22Rv1 and MB49 cancer cell lines. Base polymer, 1,4C-1,4Bis and 1,4C-1,4Bis templated and modified gold nanoparticles were compared for transgene delivery efficacies. Differences in morphology and physiochemical properties were investigated as they relate to differences in transgene delivery efficacy. There were found to be minimal differences suggestion that 1,4C-1,4Bis efficacy is not lost following use for nanoparticle modification. These results indicate that poly(amino ether)-gold nanoassemblies are a promising theranostic platform for delivery of therapeutic payloads capable of simultaneous gene silencing and bioimaging.
ContributorsRamos, James (Author) / Rege, Kaushal (Thesis advisor) / Kodibagkar, Vikram (Committee member) / Caplan, Michael (Committee member) / Vernon, Brent (Committee member) / Garcia, Antonio (Committee member) / Arizona State University (Publisher)
Created2014
Description
Environmentally responsive microgels have drawn significant attention due to their intrinsic ability to change volume in response to various external stimuli such as pH, temperature, osmotic pressure, or electric and magnetic fields. The extent of particle swelling is controlled by the nature of the polymer-solvent interaction. This thesis focuses on design and synthesis of environmentally responsive microgels and their composites, and encompasses methods of utilizing microgel systems in applications as vehicles for the adsorption, retention, and targeted delivery of chemical species. Furthermore, self-assembled microgel particles at ionic liquid (IL)-water interfaces demonstrate responsive colloidal lattice morphology. The thesis first reports on the fundamental aspects of synthesis, functionalization, and characteristic properties of multifunctional environmentally responsive microgels derived from poly(N-isopropylacrylamide) (PNIPAm) and other functional co-monomers. In particular, the uptake and release of active chemical species such as rheology modifiers into and from these ionic microgels is demonstrated. Moreover, a facile tunable method for the formation of organic-inorganic composites with Fe3O4 nanoparticles adsorbed and embedded within ionic microgel particles is explored. Additionally, the development of zwitterionic microgels (ZI-MG) is presented. These aqueous ZI-MG dispersions exhibit reversible parabolic swelling as a function of pH and display a minimum hydrodynamic diameter at a tunable isoelectric point (IEP). This study also elucidates the controlled uptake and release of surfactants from these particle systems. The extent of surfactant loading and the ensuing relative swelling/deswelling behaviors within the polymer networks are explained in terms of their binding interactions. The latter part of this thesis highlights the versatility of fluorescently labeled microgel particles as stabilizers for IL-water droplets. When the prepared particles form monolayers and equilibrate at the liquid-liquid interface, the colloidal lattice organization may re-order itself depending on the surface charge of these particles. Finally, it is shown that the spontaneously formed and densely packed layers of microgel particles can be employed for extraction applications, as the interface remains permeable to small active species.
ContributorsChen, Haobo (Author) / Dai, Lenore L (Committee member) / Chen, Kangping (Committee member) / Forzani, Erica (Committee member) / Lind, Mary Laura (Committee member) / Mu, Bin (Committee member) / Arizona State University (Publisher)
Created2015
Description
Achieving effective drug concentrations within the central nervous system (CNS) remains one of the greatest challenges for the treatment of brain tumors. The presence of the blood-brain barrier and blood-spinal cord barrier severely restricts the blood-to-CNS entry of nearly all systemically administered therapeutics, often leading to the development of peripheral toxicities before a treatment benefit is observed. To circumvent systemic barriers, intrathecal (IT) injection of therapeutics directly into the cerebrospinal fluid (CSF) surrounding the brain and spinal cord has been used as an alternative administration route; however, its widespread translation to the clinic has been hindered by poor drug pharmacokinetics (PK), including rapid clearance, inadequate distribution, as well as toxicity. One strategy to overcome the limitations of free drug PK and improve drug efficacy is to encapsulate drug within nanoparticles (NP), which solubilize hydrophobic molecules for sustained release in physiological environments. In this thesis, we will develop NP delivery strategies for brain tumor therapy in two model systems: glioblastoma (GBM), the most common and deadly malignant primary brain tumor, and medulloblastoma, the most common pediatric brain tumor. In the first research chapter, we developed 120 nm poly(lactic acid-co-glycolic acid) NPs encapsulating the chemotherapy, camptothecin, for intravenous delivery to GBM. NP encapsulation of camptothecin was shown to reduce the drug’s toxicity and enable effective delivery to orthotopic GBM. To build off the success of intravenous NP, the second research chapter explored the utility of 100 nm PEGylated NPs for use with IT administration. Using in vivo imaging and ex vivo tissue slices, we found the NPs were rapidly transported by the convective forces of the CSF along the entire neuraxis and were retained for over 3 weeks. Based on their wide spread delivery and prolonged circulation, we examine the ability of the NPs to localize with tumor lesions in a leptomeningeal metastasis (LM) model of medulloblastoma. NPs administered to LM bearing mice were shown to penetrate into LM mets seeded within the meninges around the brain. These data show the potential to translate our success with intravenous NPs for GBM to improve IT chemotherapy delivery to LM.
ContributorsHouseholder, Kyle Thomas (Author) / Sirianni, Rachael W. (Thesis advisor) / Stabenfeldt, Sarah (Committee member) / Vernon, Brent (Committee member) / Caplan, Michael (Committee member) / Wechsler-Reya, Robert (Committee member) / Arizona State University (Publisher)
Created2018
Description
Rapid development of new technology has significantly disrupted the way radiotherapy is planned and delivered. These processes involve delivering high radiation doses to the target tumor while minimizing dose to the surrounding healthy tissue. However, with rapid implementation of these new technologies, there is a need for the detection of prescribed ionizing radiation for radioprotection of the patient and quality assurance of the technique employed. Most available clinical sensors are subjected to various limitations including requirement of extensive training, loss of readout with sequential measurements, sensitivity to light and post-irradiation wait time prior to analysis. Considering these disadvantages, there is still a need for a sensor that can be fabricated with ease and still operate effectively in predicting the delivered radiation dose.
The dissertation discusses the development of a sensor that changes color upon exposure to therapeutic levels of ionizing radiation used during routine radiotherapy. The underlying principle behind the sensor is based on the formation of gold nanoparticles from its colorless precursor salt solution upon exposure to ionizing radiation. Exposure to ionizing radiation generates free radicals which reduce ionic gold to its zerovalent gold form which further nucleate and mature into nanoparticles. The generation of these nanoparticles render a change in color from colorless to a maroon/pink depending on the intensity of incident ionizing radiation. The shade and the intensity of the color developed is used to quantitatively and qualitatively predict the prescribed radiation dose.
The dissertation further describes the applicability of sensor to detect a wide range of ionizing radiation including high energy photons, protons, electrons and emissions from radioactive isotopes while remaining insensitive to non-ionizing radiation. The sensor was further augmented with a capability to differentiate regions that are irradiated and non-irradiated in two dimensions. The dissertation further describes the ability of the sensor to predict dose deposition in all three dimensions. The efficacy of the sensor to predict the prescribed dose delivered to canine patients undergoing radiotherapy was also demonstrated. All these taken together demonstrate the potential of this technology to be translatable to the clinic to ensure patient safety during routine radiotherapy.
The dissertation discusses the development of a sensor that changes color upon exposure to therapeutic levels of ionizing radiation used during routine radiotherapy. The underlying principle behind the sensor is based on the formation of gold nanoparticles from its colorless precursor salt solution upon exposure to ionizing radiation. Exposure to ionizing radiation generates free radicals which reduce ionic gold to its zerovalent gold form which further nucleate and mature into nanoparticles. The generation of these nanoparticles render a change in color from colorless to a maroon/pink depending on the intensity of incident ionizing radiation. The shade and the intensity of the color developed is used to quantitatively and qualitatively predict the prescribed radiation dose.
The dissertation further describes the applicability of sensor to detect a wide range of ionizing radiation including high energy photons, protons, electrons and emissions from radioactive isotopes while remaining insensitive to non-ionizing radiation. The sensor was further augmented with a capability to differentiate regions that are irradiated and non-irradiated in two dimensions. The dissertation further describes the ability of the sensor to predict dose deposition in all three dimensions. The efficacy of the sensor to predict the prescribed dose delivered to canine patients undergoing radiotherapy was also demonstrated. All these taken together demonstrate the potential of this technology to be translatable to the clinic to ensure patient safety during routine radiotherapy.
ContributorsSubramaniam Pushpavanam, Karthik (Author) / Rege, Kaushal (Thesis advisor) / Sapareto, Stephen (Committee member) / Nannenga, Brent (Committee member) / Green, Matthew (Committee member) / Mu, Bin (Committee member) / Arizona State University (Publisher)
Created2019
Description
This report provides information concerning qualities of methylcellulose and how those properties affect further experimentation within the biomedical world. Utilizing the compound’s biocompatibility many issues, ranging from surgical to cosmetic, can be solved. As of recent, studies indicate, methylcellulose has been used as a physically cross-linked gel, which cannot sustain a solid form within the body. Therefore, this report will ultimately explore the means of creating a non-degradable, injectable, chemically cross-linking methylcellulose- based hydrogel. Methylcellulose will be evaluated and altered in experiments conducted within this report and a chemical cross-linker, developed from Jeffamine ED 2003 (O,O′-Bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol), will be created. Experimentation with these elements is outlined here, and will ultimately prompt future revisions and analysis.
ContributorsBundalo, Zoran Luka (Author) / Vernon, Brent (Thesis director) / LaBelle, Jeffrey (Committee member) / Overstreet, Derek (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Polymer-nanoparticle composites (PNCs) show improved chemical and physical properties compared to pure polymers. However, nanoparticles dispersed in a polymer matrix tend to aggregate due to strong interparticle interactions. Electrospun nanofibers impregnated with nanoparticles have shown improved dispersion of nanoparticles. Currently, there are few models for quantifying dispersion in a PNC, and none for electrospun PNC fibers. A simulation model was developed to quantify the effects of nanoparticle volume loading and fiber to particle diameter ratios on the dispersion in a nanofiber. The dispersion was characterized using the interparticle distance along the fiber. Distributions of the interparticle distance were fit to Weibull distributions and a two-parameter empirical equation for the mean and standard deviation was found. A dispersion factor was defined to quantify the dispersion along the polymer fiber. This model serves as a standard for comparison for future experimental studies through its comparability with microscopy techniques, and as way to quantify and predict dispersion in polymer-nanoparticle electrospinning systems with a single performance metric.
ContributorsBalzer, Christopher James (Author) / Mu, Bin (Thesis director) / Armstrong, Mitchell (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12