X-ray-induced formation of biohybrid albumin/gold nanoparticles

Abstract

Nanoparticles (NPs), combined with photodynamic and photothermal therapy and nano radiotherapy, are transforming human diagnosis and cancer treatment. Biohybrid nanoparticles (bioh-NPs) prepared from non-biological nanomaterials and coated with a protein multilayer are an attractive strategy for in vivo NPs applications that require a particular surface topography to be compatible with the human body.Bioh-NPs based on gold nanoparticles (AuNPs) and albumin coating can be prepared by cross-linking induced by a gamma irradiation dose of 10 kGy, avoiding the use of additional chemical cross-linkers to stabilize the nanoconstruct.White X-rays is an alternative source to gamma-rays. Both sources are low-linear energy transfer (LET) ionizing radiation, which means that the chemical events induced by these types of radiation are assumed to be similar. Nonetheless, the interaction cross-sections of X-rays with matter are quite different from those of gamma-rays.This work explores the preparation of bioh-NPs using white X-rays as the radiation source, at two different maximum energies. Stable bioh-NPs can be prepared using absorbed doses lower than 7 kGy with both radiation sources. It turns out that the local increase of the absorbed dose in the vicinity of the original AuNPs stimulates the protein cross-linking, in addition to the solvent radicals generated due to the interactions with secondary electrons produced by the photoelectric effect. Furthermore, irradiation using the same absorbed dose but different white X-ray energies leads to the bioh-NPs of different size and/or nanostructure pattern.