A<unk>  is a dynamic coating of biomolecules, usually proteins, around the surface of a nanoparticle that forms spontaneously in colloidal nanomaterials upon exposure to biological mediums.<unk> s can form in many different patterns depending on their size, shape, composition, charge, and surface functional groups, and have properties that vary in different environmental factors like temperature, pH, shearing stress, immersed media composition, and exposing time. These coatings are also changeable according to the conditions of the biochemical and physiochemical surface interactions. Types of<unk> s are known to be divided into two categories: “hard” and “soft”. “Hard”<unk> s have higher-affinity proteins that are irreversibly bonded to the nanoparticle surface, while “soft”<unk> s have lower-affinity proteins on the nanoparticle surface that are reversibly bound. These reversibly-bound proteins allow for the biomolecules in “soft”<unk> s to be exchanged or detached over time for various applications. This process is governed by the intermolecular protein-nanoparticle and protein-protein interactions that exist within a solution. In "soft"<unk> s, it is common to observe an exchange of proteins at the surface; larger proteins with lower affinities will often aggregate to the surface of the nanoparticle first, and over time, smaller proteins with higher affinities will replace them, "hardening" the<unk> , known as the Vroman effect.
Protein corona
Matrix-core
Virulence factor
Immunogen
Antigen
Self-protein
Immune complex
Bioactive compound