Figure 3.

Size-changeable function for tumor penetration. Li et al. reported a tumor-microenvironment-responsive nanoparticle that possessed a switchable size in weakly acidic conditions. (a) Structure of drug-loaded polymeric nanoparticles composed of dendrimers and a functional polymer. (b) Schematic illustration displaying the functions and self-assembly of polymeric nanoparticles, and pH-sensitive cluster of particles at neutral pH exhibiting a size transition at tumor acidic condition. (c) The size transition of drugs/particles overcame tumor barriers in poorly permeable tumor tissue. Reprinted from Reference [23] with permission from the American Chemical Society, 2013.