Surface Engineering of Protein Nanoclusters to Overcome Mucus Barriers

Intranasal delivery of vaccines is a needle-free route that can induce mucosal antibodies and cellular responses to neutralize pathogens before entering systemic circulation, as well as systemic immunity. However, nasal secretions and mucosa are biological barriers that have been shown to inhibit delivery of antigens and nanoparticles to nasal-associated lymphoid tissue. Coatings and surface modifications on nanoparticles can alter transport and immune responses due to their interaction with biological barriers and cells. Protein nanoclusters (PNC) are one type of vaccine nanoparticle, made from protein antigens, that can be modified to change size, surface charge, and surface chemistry. Specifically, this thesis explores the interactions of mucus and model ovalbumin antigen PNC displaying different surface covalent modifications and non-covalent layer by layer coatings. Transport of the PNC in extracted mucus was characterized using bulk channel diffusion to visualize population distributions and multiple particle tracking for single particle behavior analysis. Lastly, the protein corona of these nanoparticles are identified in nasal fluids to understand their potential in vivo interaction during intranasal delivery. Overall, this thesis demonstrates the impact that surface modifications have on protein nanoparticle vaccines to overcome mucus barriers and, ultimately, improve cellular uptake and immunological processing.M.S