Nanoparticles disguised as red blood cells to evade the immune system

The development of nanoparticle platforms with long in vivo circulation half-life has long been one of the major goals in the field of cancer drug delivery. Long-circulating nanoparticles can more effectively localize to the tumor site through either passive or active targeting mechanisms. The current gold standard for bestowing long-circulating attributes involves the use of PEG, which surrounds the particles with a hydration layer and thereby prevents recognition by the mononuclear phagocyte system. Recently, a new strategy for synthesizing biomimetic nanoparticles has been inspired by the body's own long-circulating entities, red blood cells (RBCs). Such a system disguises drug nanocarriers as 'self' using membrane materials directly derived from RBCs. This method has been demonstrated to prolong particle systemic circulation half-life beyond that of the corresponding PEGylated systems. The RBC membrane-coated nanoparticles present a major breakthrough in drug delivery technology and show great promise for clinical applications. Herein we highlight the significance and the unique features of this nature-inspired nanoparticle platform and offer opinions on its future prospects.