Figure 3.

Specific spatial distributions of negative and positive surface charge can accelerate peptide transport into a mucin barrier at an ionic strength of 20 mM. Quantification of peptide accumulation inside the mucin barrier and in mucin-free buffer after 10 min. (a and b) Cationic peptide transport was strongly reduced, while anionic peptide transport was only marginally reduced by the presence of mucins. (c) Peptides composed of cationic and anionic blocks (5 amino acids each) reach higher concentrations in the mucin barrier compared to free diffusion in the buffer control, suggesting that the mucins promote transport of these peptides. (d) Transport of the alternate peptide, a molecular isomer of the block peptide, shows no mucin dependent change in transport rate. This indicates that the detailed charge distribution is critical for the transport properties of the peptide. (Movie S1 in the Supporting Material)