When nanoparticles enter a biological fluid, such as blood, a dynamic interaction occurs between the nanoparticle surface and the proteins present in the fluid. This results in the formation of a hard corona composed of tightly bound proteins and a soft corona consisting of loosely bound proteins. These interactions are governed by several factors, including the surface properties of the nanoparticles, the concentration and type of proteins in the fluid, and environmental conditions such as pH and temperature.
