Nanocoating Immune Stealth: Protein Corona on a Transplant Surface

The moment a transplanted organ or implant meets blood, plasma proteins begin adsorbing onto its surface, forming a "corona" that the immune system reads to decide friend or foe. This simulator renders that race in real time: plasma opsonin particles diffuse via Brownian motion toward a nanocoated organ surface, and a PEG brush layer of tunable grafting density exponentially suppresses their odds of sticking on each collision. Turn the coating density down and the surface floods with adsorbed protein until a macrophage sentinel docks and rejection begins; turn it up and the surface stays immunologically invisible far longer, exactly the effect PEGylated and zwitterionic "stealth" coatings are engineered to produce on real vascular grafts and encapsulation devices.