Boston Ivy Disk-Inspired Pressure-Mediated Adhesive Film Patches.

Boston ivy (Parthenocissus tricuspidata) climbs brick walls using its tendril disks, which excrete a sticky substance to perform binding and attachment. While the cellular structures and adhesive substances involved have been identified for decades, their practical applicability as an adhesive has not yet been demonstrated. A Boston ivy disk-inspired adhesive film patch system is reported in which structural and compositional features of the Boston ivy disk are mimicked with a form of thin adhesive film patches. In analogy to the sticky disk of a mature ivy in which porous microchannels are occupied by catechol-containing microgranules on the bound site, 3,4-dihydroxylphenylalanine bolaamphiphile nanoparticle (DOPA-C7 NP)-coated alginate microgels are two-dimensionally positioned into the cylindrical holes that are periodically micropatterned on the flexible stencil film. Finally, it is demonstrated that the pressurization of the patch breaks the microgels filled in the holes, releasing the polysaccharides and leading to crosslinking with DOPA-C7 NPs via ligandation with combined Ca²⁺ and Fe³⁺ ions, thus enabling development of a pressure-mediated adhesion technology.