Optical nanoscopy for elucidating nano–bio interactions: a one health perspective

Advances in nanotechnology have led to an increased adoption of nanoengineered materials in several areas (including, but not limited to, medicine, food, cosmetics, electronics, and energy), implying their direct or indirect contact with the human body or their dispersion in the environment. In the “Era of One Health”, the concept of exposome is becoming central, thereby demanding for a deeper understanding of the relationships and interactions of “stressors” in the environment and their biological effects. The fast evolution of super-resolution microscopy (also called optical nanoscopy) greatly contributes to the characterization of biological structures and cellular dynamics at the nanometer scale, helping to unveil the intricate nature of the interactions occurring between nanomaterials and biological systems (nano–bio interactions), which need to be elucidated in view of a safe and sustainable application of nanotechnology. In this review, the contribution of optical nanoscopy (with a focus on far-field fluorescence-based techniques) to the characterization and understanding of nanomaterial interactions with biological systems at the single-particle and molecular scale is enlig