Nanoparticle behavior and stability in biological environments

Abstract Recent years have witnessed the rapid growth of biological and medical applications based on inorganic nanoparticles (NPs), either as therapeutic and/or as diagnostic nanotools. That said, albeit the field of bionanotechnology is constantly fed by new proof-of-concept studies, only few nanobiotools (that is, nanomedicines, NP-based biosensors, or bioimaging agents) have been successfully commercialized. This is mostly motivated by the intrinsic complexity and dynamism of biological environments (fluids, cells, tissues, or whole animals), which precludes predicting in a straightforward manner the behavior of NPs when they are immersed in such environments. In this chapter, we discuss the most important factors influencing NP's behavior in biological environments: NP integrity, protein corona, and colloidal stability. Furthermore, the effect of such factors on the NP's function is discussed in the context of recent, highly relevant examples from the literature. We hope that both early-stage and experienced researchers will find it valuable for designing NPs with enhanced bioperformance.