Multi-functionalized gold nanoparticles for the delivery of biomolecules

Abstract

This thesis is focused on the use of gold nanoparticles (AuNPs) for the delivery of biomolecules. These nanomaterials are of great interest in the nanomedicine field due to their low toxicity, high biocompatibility, and easy-to-tailor surface, making them suitable for different bio-applications. For this project, we focused on their potential role as carriers of biomolecules, such as oligonucleotides, plasmids or proteins, to treat cancer-related diseases. In order to fulfill this objective, a novel system based on the multi-functionalization of gold nanoparticles with modified polymers has been developed. The gold nanoparticles formulation developed consists of a combination of polymeric mixed layer of polyethylene glycol (PEG) and branched polyethylenimine (bPEI), and layer-by-layer assembly of bPEI through a sensitive linker. The nanostructures generated here provide a non-toxic and powerful system for the electrostatic conjugation of different biomolecules, being mainly optimized for the delivery and transfection of oligonucleotides in tumoral cells. The designed system was optimized using different gold nanoparticles core sizes and branched polyethylenimines chains, leading to the obtentions of 12 different formulations, which were evaluated in terms of stability, reproducibility, toxicity, conjugation and transfection efficacy. The one with the best properties was employed as a nanocarrier of antisense oligonucleotides to downregulated tumoral cell lines carrying mutant p53 proteins. Additionally, a novel building block for the solid synthesis of oligonucleotides was developed. The building block, consisting of a sensitive stimulus cross-linker attached to a controlled pore glass (CPG) solid support. The oligonucleotides prepared with this derivative were able to be conjugated easily with biomolecules through the formation of a disulfide moiety