Mucoadhesive micropatterns for enhanced grip

The main challenge in designing diagnostic devices able to move along the colon is their locomotion method. Manipulating friction with the colonic surface is a key requirement for their safe and atraumatic propagation. One possible solution is to generate friction by means of adhesive forces. For this purpose, a diagnostic device can be covered with mucoadhesive films that stick to the mucus layer of the colonic surface and generate high static friction. This paper investigates whether micropatterning the mucoadhesive films is able to enhance the grip with the colonic surface even more than flat mucoadhesive films. This idea is inspired by the sponge-form adhesive secretion of sea stars which is released by numerous tubular feet. Experiments in vitro showed that the frictional performance of mucoadhesive micropatterns exceed that of non-patterned mucoadhesive films. Moreover, the grip achieved by mucoadhesive micropatterns is far higher than the grip generated by non-mucoadhesive micropatterns made of an elastomeric material. Mucoadhesive micropatterned films also avoid the risk of damaging the colonic surface, since they interact only with the mucus layer and leave the colonic epithelium unaffected.