Figure 3. In-vitro delivery of hydrophilic compounds by cnidocysts in a gel formulation.

(a) Activation of cnidocyst gel over isolated porcine ear skin with 0.05% toluidine blue dye solution for 5 min. Following application the skin was thoroughly washed and then photographed. Black arrows, penetrating cnidocyst. White arrow, skin hair bundle. Scale bar, 100 µm. (b) The skin was tape-stripped 30 times to remove the stratum corneum and then photographed. Scale bar, 100 µm.