Introducing gold nanoparticle bioconjugates within the biological machinery
- Autores: Lorena García Fernández
- Directores de la Tesis: Victor Franco Puntes (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2013
- Idioma: español
- Tribunal Calificador de la Tesis: Wolfgang Parak (presid.), Julia Lorenzo Rivera (secret.), Jesús Martínez de la Fuente (voc.)
- Materias:
- Texto completo no disponible (Saber más ...)
- Resumen
The rapid development in Nanotechnology during the past few decades offers wide prospects in using micro- and nanoscale materials in different areas of industry, technology and medicine. However, their safe and efficient use and implementation in such areas require much greater control over their physicochemical properties and their related molecular interactions in living systems. Current knowledge in the scientific community agrees that a considerable gap exists in our understanding of such Nano-Bio interface. As a step forward in this direction, this Thesis work aimed to provide insights into the formation of rationally designed gold nanoparticle (Au NP) bioconjugate architectures to modulate and understand cellular interactions and processes.
In such a context, the first part of this Thesis is focused on the synthesis of cationic Au NPs and their interactions with cells. A first strategy was developed in which the synthesis of positively charged Au NPs was performed by using simultaneously a weak and a strong reducer. It is shown that both reducers act sequentially in a one-pot synthesis to yield monodisperse cationic Au NPs with sizes comprised between 10.3 nm and 19.7 nm. A two-step seeding growth method is also described in which preformed Au NPs are grown larger (up to ~28 nm in size) by addition of fresh precursor solution and a weak reducer. A second strategy faces the rising demand of cationic Au NPs of different sizes and ligands by employing an organic-aqueous phase transfer methodology. Important benefits resulted from the combination of organic and aqueous synthetic methods. This strategy was optimized to prepare cationic Au NPs of 4.6, 8.9 and 13.4 nm in diameter using a positively charged alkanethiolate ligand. In addition, its practical application was demonstrated by producing ~ 13-nm-in-size cationic and anionic peptide-Au NP bioconjugates. The physicochemical properties of these bioconjugates in cell culture media as well as their uptake and toxicity on human fibroblast cells are discussed.
The second part of this Thesis is focused on the rational functionalization of Au NPs with antibodies and investigating their interactions with cellular receptors. A site-directed chemistry was explored to prepare Antibody-Au NP bioconjugates with controlled ratio and orientation of bioconjugation. The formation of well-defined bioconjugates made possible the creation of novel NP-based assemblies using antibody-antigen cross-links. This strategy was also explored for the conjugation of a biologically relevant antibody (Cetuximab) with Au NPs. Cetuximab-Au NP bioconjugates of controlled configuration and multivalency were used to examine their interaction with the cell surface receptor EGFR (epidermal growth factor receptor), a receptor tyrosine kinase overexpressed in a large number of cancers.
