Research highlights: comparing the biological response of nanoparticle solid solutions
Scientific advances in the field of nanotechnology have led to the wide-scale use of engineered nanomaterials, resulting in an increased demand to understand the biological impact of these materials when released to the environment. This demand has led to an evolving field of science focused specifically on interactions at the nano–bio interface, where researchers investigate the biological responses of a wide range of organisms to engineered nanomaterials. The majority of investigations into the nano–bio interface are focused on the biological response of single-phase nanomaterials, yet engineered nanomaterials are often more complex than a single-phase nanomaterial. Many engineered nanomaterials can be described as solid solutions (or alloys) where multiple types of cations (and/or anions) are present in different ratios, and properties such as spin state, valence charge, and lattice constant can be tuned by changing the atomic composition. Research at the nano–bio interface must go beyond investigating the biological response of single-phase nanomaterials and include a systematic approach to predict how the biological interactions of nanomaterial solid solutions can be controlled via systematic changes in chemical composition. In this highlight, we focus on four publications that use a range of experimental methods to delineate the interactions of solid solutions composed of either Au metal or ZnO solid oxide on a variety of organisms. The first highlighted work tunes the composition of Au–Pt nanoparticles for antibacterial activity. The second article investigates the reprotoxicity of Au–Ag nanoparticles. The third highlighted work shows that Fe–ZnO nanoparticles demonstrate a reduced toxicity when compared to ZnO. Finally, the fourth study presents an in silico design strategy for cancer specific Fe–ZnO nanoparticles. Together, these four studies reveal the wide range of chemical compositions that are accessible in nanomaterial solid solutions and demonstrate that careful modifications in compositional phase space can result in selective nano–bio interactions.