The uniqueness of MPPs lies in their ability to move through the mucus layer without being trapped or expelled. Traditional nanoparticles often become ensnared within the viscous mucin fibers, reducing their effectiveness. MPPs are designed with surface modifications that allow them to avoid interactions with mucins. This is often achieved by coating the particles with a dense layer of polyethylene glycol (PEG), a process known as PEGylation. This coating gives them a "slippery" surface, enabling them to penetrate mucus more effectively.
