Biological identity of nanomaterials: Opportunities and challenges

The emergence of nanoparticles (NPs) has attracted tremendous interest of the scientific community for decades due to their unique properties and potential applications in diverse areas, including drug delivery and therapy. Many novel NPs have been synthesized and used to reduce drug toxicity, improve bio-availability, prolong circulation time, control drug release, and actively target to desired cells or tissues. However, clinical translation of NPs with the goal of treating particularly challenging diseases, such as cancer, will require a thorough understanding of how the NP properties influence their fate in biological systems, especially in vivo. Many efforts have been paid to studying the interactions and mechanisms of NPs and cells. Unless deliberately designed, the NPs in contact with biological fluids are rapidly covered by a selected group of biomolecules especially proteins to form a corona that interacts with biological systems. In this view, the recent development of NPs in drug delivery and the interactions of NPs with cells and proteins are summarized. By understanding the protein-NP interactions, some guidelines for safety design of NPs, challenges and future perspectives are discussed.