Radiosynthesis of gold/albumin core/shell nanoparticles for biomedical applications

ACHILLI, ESTEFANIA; GRASSELLI, M.; CONSTANZA FLORES

Cancun

Congreso; XXV International Materials Research Congress 2016; 2016

Sociedad Mexicana de Materiales / Materials Research Society

Functionalization of Gold nanoparticles (AuNPs) surface with different biomolecules is used for several decades in rapid diagnostics tests. In last decades, AuNPs have been demonstrated can be used in therapy and imaging. This is due biocompatibility and they exhibit unique properties, dependent on their size, shape and coating. Those characteristic will allow to generate nanomaterials as platforms by therapy and diagnoses, or combination both, to generate theranostic nanoparticles.The aim of this work is to prepare and characterize AuNPs coated with human serum albumin (HSA) and bovine serum albumin (BSA) multilayers. These core/shell NPs are capable to maintain the functional properties of proteins and optical properties of AuNPs. Recently, our working group described the formation of BSA NPs from radiation-induced crosslinking with 60Co gamma rays in an ethanol solution of Albumin [1]. It is important to note that the size of the NPs obtained depends essentially on the initial concentration of solvent added. These NPs retain a large percentage dimensional structure of proteins that comprise it.In this workt is proposed to perform a preparation method with the addition of AuNPs in the reaction media. First, AuNPs were 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 concentrated Alb solution followed by cold ethanol to induce the aggregation. The water/ethanol suspension containing Alb and AuNPs were irradiated at 10 kGy dose under oxygen free atmosphere.The Au/Alb NPs were prepared in three concentrations of ethanol (30, 40 and 50% v/v) and different albumins concentration. The Au/Alb NPs were characterized by UV-visible and infrared spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). In the UV-visible spectrum of NPs prepared with 30% ethanol was showed surface plasmon peak at about 532 nm, demonstrating the presence of AuNPs. Using 40% and 50% v/v ethanol are not observed the plasmon peak. When compared to the spectrum of naked AuNPs, a slight shift of the wavelength was observed. By DLS, it was found a new peak 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, confirming the presence of albumin. Furthermore, the diameter of the NPs was determined, showing lower than those obtained by DLS values. In the FT-IR spectrum Au/Alb NPs, was not found loss of the secondary protein structure in the presence of Au. Subsequently, the stability of Au/Alb NPs in different buffers and cell media were assessed. These NPs were stable at different conditions. In conclusion, Au/Albumin NPs have been prepared by a novel cross-linking technique and characterized by several spectroscopic and microscopy techniques. NPs showed a core / shell composition with low aggregationAlbumin coating do not interfere with the optical properties of Au. and, according to preliminary studies, they show a better estability under physiological conditions.[1] Soto Espinoza, S.L., et al., Radiation synthesis of seroalbumin nanoparticles. Radiation Physics and Chemistry, 2012. 81(9): p. 1417-1421.