Date

2017

Department or Program

Biological Chemistry

Primary Wellesley Thesis Advisor

Nolan Flynn

Additional Advisor(s)

Andrew Webb

Additional Advisor

Donald Elmore

Abstract

Although the behavior of nanomedicines is well characterized, understanding of the difference between the synthetic and biological identity of nanoparticles (NPs) is limited. To expand our knowledge base, we probe the stability of NPs and protein corona formation in increasingly in vivo-like conditions. The protein corona consists of various proteins at different relative abundances, rapidly forming when NPs are exposed to protein-rich environments. We begin our investigation through the synthesis and conjugation of 11.2 nm, citrate-stabilized gold nanoparticles (AuNPs). Coating AuNPs with low fouling polymers, such as poly(ethylene glycol) (PEG) or poly-EK (PEK), increases the biocompatibility, biodistribution, and physiological half-life of AuNPs. We evaluate the protein corona formation in the presence of two types of polymer coatings: methoxy-terminated PEG (MPEG) and PEK. Using UV-visible absorption spectroscopy, dynamic light scattering (DLS), and Zeta-potential, we first monitor size, charge, and monodispersity to confirm functionalization. Second, incubating each AuNP model with bovine serum albumin (BSA) and lysozyme under various conditions confirms that proteins adsorb to our models and that their adsorption changes the surface chemistry of the NPs. Finally, protein corona formation in complex media is evaluated by incubating the AuNPs models with increasingly concentrated pooled human serum. Through purification, digestion, and analysis via HPLC/MS-MS, UV-Vis, DLS, we determine the types and amount of protein that form the corona. In addition, by studying corona formation around MPEG- and PEK-conjugated maleimide polystyrene magnetic beads, we isolate the role that the gold nanoparticle and stealth coating may each play. The stability of the AuNPs in human serum is also analyzed through ICP-OES. This study aims to inform nanomedicine design and provide insight into biological identity of NPs.

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