RADIATION-INDUCED PREPARATION OF GOLD/ALBUMIN CORE/SHELL NANOPARTICLES

ACHILLI, ESTEFANIA; GRASSELLI, M.; CONSTANZA FLORES

Peninsula of Giens

Simposio; 12th meeting of ionizing radiation and polymers symposium, IRaP; 2016

CEA - France

Functionalization of the surface of Gold nanoparticles (AuNPs) with different biomolecules has been used for several decades in rapid diagnostics tests. In last decades, AuNPs have been demonstrated they use in therapy and imaging. This is due biocompatibility and their unique properties, dependent on their size, shape and coating. Those characteristic will allow preparing nanomaterials as platforms by therapy and diagnoses, or combination both, to generate theragnostic nanoparticles.Preparation of AuNPs with a single monolayer coating of protein is easy to achieve by physisorption methods. However, the main core of the protein is denatured and the stability of the nano-constract is relatively low. In addition interaction with a dynamic ?protein corona? has been described when these NPs are in presence of high concentration of proteins, such as in the plasma.Recently, our research group has described for the first time the preparation of protein NPs using radiation-induced crosslinking with 60Co gamma rays and accelerated electrons [1,2]. The ethanol/water mixture of Albumin solution generates a dynamic equilibrium between free and aggregate proteins, which can be stabilized by ionizing radiation [2]. In this work is proposed a novel method to prepare Au/Albumin NPs by radiation-induced crosslinking. First, AuNPs of 30 nm diameter are prepared by chemical reduction of Au salt in aqueous medium. AuNPs were pre-treated with dilute protein solution to stabilize semi-denatured forms of the protein (monolayer coating) and subsequently addition of higher amount of Albumin followed by cold ethanol to induce the aggregation. The water/ethanol suspension is irradiated in a 60Co source with a minimum of 5 kGy dose under oxygen free atmosphere, to obtain a stable coating. A similar crosslinking mechanism than in protein NPs preparation is expected.The Au/Albumin NPs were characterized by UV-visible and infrared spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). By DLS, it was found a new NP population with an average diameter of about 60 nm. Moreover, TEM images showed that the NPs have spherical shape and the presence of a low-density halo around the metal core confirms the presence of Albumin. Au/Albumin NPs showed better stability under physiological conditions and the Albumin coating do not interfere with the optical properties of Au. References [1] Espinoza, S. L. S., Sánchez, M. L., Risso, V., Smolko, E. E., & Grasselli, M., Radiation synthesis of seroalbumin nanoparticles. Radiat. Phys. Chem., 81 (2012), 1417-1421. [2] Achilli, E., Casajus, G., Siri, M., Flores, C., Kadłubowski, S., Alonso, S. D. V., & Grasselli, M. Preparation of protein nanoparticle by dynamic aggregation and ionizing-induced crosslinking. Coll. Surf. A, 486 (2015), 161-171.