Development of functionalized nanoparticles for immunoassay and gene delivery

Abstract

Nanoparticles have been widely used in biological and biomedical fields. To achieve certain purpose, nanoparticles should be functionalized with diverse molecules through genetic or chemical modification. Therefore, we developed genetically functionalized nanoparticles for improved systems by simple construction. In chapter 1, we developed genetically functionalized ferritin nanoparticles for immunoassay and imaging. Ferritins are known as self-assembled protein nanoparticles, and we fused human IgG-specific repebody to N-terminal heavy-chain ferritin subunit to construct repebody-ferritin nanoparticles. The repebody-ferritin nanoparticles were shown to have a three-order of magnitude higher binding affinity toward human IgG than free repebody due to multivalency. Also, the dye-labeled repebody-ferritin nanoparticles were applied for immunoassay such as western blot, cell imaging and flow cytometry. As a result, the repebody-ferritin nanoparticles generated much stronger fluorescent signals than monovalent repebody. In chapter 2, we described a targeted gene delivery system through electrostatic assembly. To deliver genetic molecules to specific cells, we used PAMAM dendrimers and EGFR-specific repebody. A polyanionic peptide was incorporated into EGFR-specific repebody to generate the assembly of dendrimer complex through electrostatic interaction. The resulting dendrimer complex showed an increased efficiency with negligible cytotoxicity in a receptor-specific manner. We confirmed the internalization of the dendrimer complex and dissociation of plasmid DNA from the complex. In this study, we demonstrated the utility of genetically functionalized nanoparticles for immunoassay and gene delivery. The resulting nanoparticles can be effectively used for sensitive immunoassay and efficient targeted gene delivery.