Graduation Semester and Year

2013

Language

English

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering

Department

Bioengineering

First Advisor

Wei Chen

Abstract

Recently, mapping and profiling of specific tumor biomarkers characterizing cancer cells, followed by understanding of signal cascades involved in the pathogenesis of tumors (targeted therapy), as well as diagnosis in early stages, have become promising topics in cancer research. Since, the most considerable limitations of conventional therapies and diagnostic modalities are associated with nonspecific targeting; designing intelligent new anti-cancer nanocarries improved by targeting biomolecules could enhance therapeutic efficiencies as well as diagnosis in early stage of cancer. Active targeting which is based on the surface accessibility and the high level of expression of specific cancer antigens has attracted much attention in the last decade, since it could result in highly efficient treatments and markedly reduced systemic toxicities. In this study two different nanoparticles (NPs) synthesized in this lab were used in order to conjugate with variety of biomolecules to investigate cancer cells targeting. Firstly, Sr3MgSi2O8:Eu2+, Dy3+ persistent luminescence NPs were conjugated to folic acid (FA) through a simple EDC/NHS (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide /N-hydroxysuccinimide) chemistry. Then, some characterization studies were conducted. The luminescent properties of the NPs after conjugation were studied. UV-Vis Absorption spectra was used to confirm conjugation, as well as calculating the conjugation efficiency. Zeta potential was performed using dynamic light scattering (DLS) device to confirm the FA conjugation to NPs. The size of NPs after conjugation was measured using DLS. Cell viability studies were done using MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). Finally fluorescent imaging was done using PC-3 cells (negative for folic acid), MCF-7 (positive for folic acid), and KB cells (positive for folic acid) to compare the cellular uptake and confirm targeted delivery. These persistent luminescence NPs could be further conjugated with photosensitizer so they can be used for targeted photodynamic therapy especially for breast cancer cells. Also the same NPs were conjugated to cyclic RGDfK and fluorescent imaging was carried out using MDA-MB-231 breast cancer cell line as positive for αvβ3 integrin receptor and MCF-7 as negative for αvβ3 integrin receptor to compare the cellular uptake and confirm targeted delivery. The main reason for choosing RGD peptide over folic acid was the more specificity of RGD peptide to breast cancer cells as compared to folic acid. Moreover, the ZnS:Mn luminescent NPs were used to conjugate to prostate specific membrane antigen (PSMA) inhibitor. It has been shown that inhibitors of PSMA strongly bind to PSMA expressed on prostate cancer cells. LNCaP and PC-3 cell lines were used as positive and negative for PSMA receptors in fluorescent imaging to compare the cellular uptake and confirm targeted delivery. Finally, the persistent luminescence NPs were conjugated to R11-SH peptide and fluorescent Imaging was performed on LNCaP and PC-3 cells as models for prostate cancer cell lines and the uptake was studied. Consequently, based on all the results related to different biomolecules, cellular uptake and targeting of luminescent NPs could be enhanced, by conjugation to variety of biomolecules, which are specific for breast and prostate cancer cells, in a receptor dependent manner.

Disciplines

Biomedical Engineering and Bioengineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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