General structure of mannosylated PEG nanocarriers (NCs). The bracketed section depicts the Man-Man spacer distance, which consists of a short linear monodisperse PEG chain (mPEG) of 6, 12 and 20 PEG units corresponding to 25, 46, or 75 Å (extended lengths) and a mannose attached to Ser resulting in Man-Man distances of 39, 56 or 89 Å. The PEG carrier in the NC is a much larger polydisperse linear PEG (5, 12, 20 or 30 kDa).