Protein-based supramolecular adhesive capable of on-demand adhesion and anti-adhesion for preventing undesired epidural tissue adhesion

The undesired adhesion between the dura mater and surrounding tissues is a great challenge in the clinical treatment of spinal stenosis and disc herniation, and this condition can typically lead to failed back surgery syndrome (FBSS) and persistent or recurrent lumbosacral pain or sciatica. Here, a protein-based supramolecular adhesive featured with wet adhesion and on-demand anti-adhesion via non-covalent interactions between anionic glycyrrhizic acid (GA) nanofibers and N-α-lauroyl-arginine ethyl ester hydrochloride (LAE) dispersed zein colloid (zein-LAE). By controlling the crosslinking density of the zein-LAE/GA supramolecular polymers, the adhesion and anti-adhesion could be conveniently regulated. In detail, suitable amount of GA improved the adhesion strength of the zein-LAE/GA supramolecular adhesives, whereas excessive GA caused the surface curing and anti-adhesion. It was proposed that the anti-adhesion outcome was attributed to the enhanced cross-linking density and Young’s modulus of the supramolecular polymers, and the declined freedom of the binding groups. The excellent biocompatibility and biodegradation enabled the zein-LAE/GA supramolecular polymers to function as easy-to-implement Janus implants for the in vivo prevention of postoperative epidural adhesion in a rat model. In conclusion, the physical barrier of the Janus implant together with the anti-oxidation and anti-inflammatory effects of the GA component played a synergistic role in achieving epidural anti-adhesion.