(206c) Adsorption of Serum Proteins Onto Carbohydrate-Functionalized Polyanhydride Nanoparticles Influences Dendritic Cell Activation and Uptake

Polyanhydride nanoparticle-based subunit vaccines have demonstrated significant promise for inducing adaptive immune responses. When these particles are administered parenterally, their surface characteristics may be modified by the adsorption of serum proteins. This surface modification could affect how the particles interact with antigen presenting cells. Previous work suggests that serum protein adsorption can be tailored by controlling the particle surface chemistry. The purpose of these studies was to investigate the differential adsorption of mouse serum proteins onto the surface of carbohydrate-functionalized polyanhydride nanoparticles. Furthermore, it was of interest to determine how this adsorption influenced bone-marrow derived dendritic cell (BMDC) activation and particle uptake. Nanoparticles based on sebacic acid, 1,6-bis-(p-carboxyphenoxy)hexane, and 1,8-bis-(p-carboxyphenoxy)-3,6-dioxaoctane were fabricated using anti-solvent nanoprecipitation. The particle surface was functionalized with di-mannose or glycolic acid using ethylenediamine. The functionalized nanoparticles were characterized by energy dispersive spectroscopy, zeta potential, and a phenol-sulfuric acid assay. In these experiments, mouse serum was incubated with nanoparticle suspensions to enable serum protein adsorption. The adsorbed proteins were eluted and characterized using 2-D gel electrophoresis. Protein concentrations were measured using a bicinchoninic acid assay. Quantum-dot loaded nanoparticles that were sham- or serum-treated were then incubated with BMDCs for 48 hours. Nanoparticle internalization and BMDC maturation markers MHC II, CD206, and CD86, were assessed via flow cytometry. In addition, BMDC production of IL-1β, IL-10, TNF-α, IL-6, and IL-12p40 following nanoparticle stimulation was measured using multiplexed cytokine assays. The results showed that functionalized particles had higher levels of adsorbed serum proteins as compared to non-functionalized controls. BMDCs internalized glycolic acid functionalized nanoparticles most effectively, while all the functionalized nanoparticles activated BMDCs relative to the non-functionalized nanoparticles. These results demonstrate that particle functionalization can modulate the levels of serum protein adsorption, BMDC uptake, and cytokine production.  Together our results suggest that the rational design of carbohydrate functionalized nanoparticles can be developed and utilized as vaccine delivery vehicles.