Effects of neutron activation on the biodegradable polymer PEG-Thiol associated with gold nanoparticles

Resumo

Polyethylene glycol (PEG) is a stable polymer widely used in cosmetics and pharmaceutical products and is not metabolized by the body. This study evaluates the association of PEG with gold nanoparticles (AuNPs) for imaging and therapy applications, exploring the effects of neutron activation on the AuNPs-PEG complex. The samples were irradiated in the Argonauta reactor, with a neutron flux of 10⁸n.cm⁻¹·s⁻², and characterized by techniques such as Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and UV-visible absorption Spectroscopy (UV-vis). The formation of monodisperse AuNPs with an average diameter of 28 ± 0.6 nm was confirmed by TEM and DLS. After irradiation, aggregation of the nanoparticles was observed, increasing the size to 644 nm and shifting the UV-Vis absorption peak to 550 nm. FTIR and NMR analyses confirmed the integrity of the post-irradiation PEG. Gamma spectrometry confirmed the energetic characteristic of gold with a half-life of 2.7 days. The coating of AuNPs with PEG proved to be functional, preserving the beneficial properties of the polymer, and being suitable for use as a carrier for antitumor drugs or as diagnostic contrast agents. Thus, it was observed that neutron activation does not compromise the characteristics of PEG, validating its effectiveness as an AuNP coating.