Browsing by Author "Figueroa, Elizabeth Raquel"

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    Gold Nanoparticle Dendrimer Conjugates for Gene Therapy
    (2015-04-24) Figueroa, Elizabeth Raquel; Drezek, Rebekah; Suh, Junghae; Wong, Michael; Foster, Aaron
    Gene therapy is a promising treatment that has enormous potential for the management of numerous diseases of acquired and innate origin. Viral delivery vectors are successful in delivering therapeutic DNA, but their efficacy is circumvented by immunogenicity and cost. Non-viral vectors face other issues of inflammatory response, colloidal stability, and low transfection efficiency. Gold nanoparticles (AuNPs) have emerged as attractive nanocarriers for gene delivery. AuNPs are bioinert, easily synthesized, and possess rich surface chemistry that facilitates versatile functionalization. Therefore, AuNPs provide an excellent platform for gene delivery. Polyamidoamine (PAMAM) dendrimers are commercially available cationic branched polymers in which growth branches from a core molecule. Their physiochemical properties make PAMAM dendrimers well suited for gene delivery applications. In this thesis, PAMAM dendrimers are functionalized on the surface of small AuNPs yielding a unique class of gene delivery vectors termed AuPAMAM vectors. We begin by establishing the synthesis and characterization of AuPAMAM vectors, showing that AuPAMAM colloidal stability and DNA condensation ability are dependent on the PAMAM conjugation reaction rate, and that this reaction rate can be altered to enhance transfection efficiency in vitro. Then, we further investigate the influence of each chemical component of the bottom-up AuPAMAM synthesis process by systematically probing each step of the reaction and analyzing its effect on the overall transfection efficiency and cytotoxicity. Finally, in order to clarify the mechanism underlying the differential transfection efficiency seen across many cell lines and tissues, the AuPAMAM vectors are tracked intracellularly over time in vitro using confocal imaging, cellular TEM and flow cytometry. Together, this thesis demonstrates that AuPAMAM conjugates present attractive candidates for non-viral gene delivery due to their commercial availability, ease of fabrication and scale-up, high yield, high transfection efficiency and low cytotoxicity. Additionally, this thesis demonstrates the need to characterize the tissue-specific transfection hurdles vectors face in order to improve application-specific non-viral vector design.
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    In vivo Gold Nanoparticle Delivery of Peptide Vaccine Induces Anti-Tumor Immune Response in Prophylactic and Therapeutic Tumor Models
    (Wiley, 2015) Almeida, Joao Paulo Mattos; Lin, Adam Yuh; Figueroa, Elizabeth Raquel; Foster, Aaron Edward; Drezek, Rebekah Anna
    Gold nanoparticles (AuNPs) are promising vehicles for cancer immunotherapy, with demonstrated efficacy in immune delivery and innate cell stimulation. Nevertheless, their potential has yet to be assessed in the in vivo application of peptide cancer vaccines. In this study, it is hypothesized that the immune distribution and adjuvant qualities of AuNPs could be leveraged to facilitate delivery of the ovalbumin (OVA) peptide antigen and the CpG adjuvant and enhance their therapeutic effect in a B16-OVA tumor model. AuNP delivery of OVA (AuNP-OVA) and of CpG (AuNP-CpG) enhanced the efficacy of both agents and induced strong antigen-specific responses. In addition, it is found that AuNP-OVA delivery alone, without CpG, is sufficient to promote significant antigen-specific responses, leading to subsequent anti-tumor activity and prolonged survival in both prophylactic and therapeutic in vivo tumor models. This enhanced therapeutic efficacy is likely due to the adjuvant effect of peptide coated AuNPs, as they induce inflammatory cytokine release when cultured with bone marrow dendritic cells. Overall, AuNP-mediated OVA peptide delivery can produce significant therapeutic benefits without the need of adjuvant, indicating that AuNPs are effective peptide vaccine carriers with the potential to permit the use of lower and safer adjuvant doses during vaccination.