We describe the phenomenon of electroadhesion (EA) i.e., adhesion that can be switched on by an electric field. EA is induced between a pair of cationic and anionic materials due to electrophoresis of chain segments across the interface. Typically, we fix the cationic material to be a covalently crosslinked hydrogel made by polymerizing cationic monomers. The anionic material could be another gel, or more interestingly, it could be a biological tissue. We have discovered that cationic gels can be adhered by EA to tissues across all of biology. This includes tissues from animals, including humans and other mammals, birds, fish, reptiles, etc. Gels can also be adhered to soft tissues from plants, including fruits and vegetables. In all cases, EA is induced by a low electric field (DC, 10 V) applied for a short time (20 s). After the field is removed, the adhesion is permanent. The adhesion can also be reversed by applying the field with opposite polarity. The higher the concentration of anionic polymers in a tissue, the stronger its adhesion to cationic gels. One potential application of EA is in sutureless surgery, i.e., to seal cuts or tears in tissues by adhereing a gel patch over the injured tissue. Preliminary studies with mice show that surgeries can indeed be performed safely and effectively using EA.
References:
[1] L. K. Borden, A. Gargava, S. R. Raghavan. Reversible electroadhesion of hydrogels to animal tissues for suture-less repair of cuts or tears. Nature Communications, 2021, 12, 4419.
[2] L. K. Borden, A. Gargava, U. J. Kokilepersaud, S. R. Raghavan. Universal way to “glue” capsules and gels into 3D structures by electroadhesion. ACS Applied Materials & Interfaces, 2023, 15, 20014.
[3] L. K. Borden, M. G. Nader, F. A. Burni, S. M. Grasso, I. Orueta-Ortega, M. Srivastava, P. Montero-Atienza, M. Erdi, S. L. Wright, R. Sarkar, A. D. Sandler, S. R. Raghavan. Switchable adhesion of hydrogels to plant and animal tissues. Advanced Science, 2025, 12, 2411942.