Physicochemical Properties of Protein-Coated Gold Nanoparticles in Biological Fluids and Cells before and after Proteolytic Digestion

摘要

Owing to their size-related physical and chemical properties, nanoparticles (NPs) are not only considered promising tools for various fundamental in vitro and in vivo studies, but also for many biomedical applications, particularly as imaging contrast agents and drug-delivery vehicles, However, little is known about the fate of NPs in biological systems, especially in terms of their physicochemical properties after their internalization by cells and organisms. Whereas nearly all biorelevant physicochemical properties of NPs can be characterized well before their uptake by cells, they are hard to assess intracellularly. Important parameters, such as NP uptake, their intracellular localization, and toxicity, can be readily determined by means of various microscopy techniques (e.g. by fluorescence microscopy or transmission electron microscopy) or by a variety of viability assays. Although the assessment of these parameters has been the subject of extensive studies during the last decade,it is still necessary to increase our understanding of what happens to NPs once they are taken up by cells. In particular, the physicochemical characterization of internalized NPs has scarcely been reported so far.