Fig. 9. (a) The structure of the mucus in human airways as proposed by Rubinstein et al.57 (b) The function of molecular walking of influenza in crossing the mucus. (I) When there is no interaction, particles are repelled by the charged brush. (II) Particles that have an affinity for sialic acid are entrapped. (III) Influenza, which binds and cleaves sialic acid, can walk through the mucus.
