Biomimetic catalysis design enables controllable and adjustable cold-set protein adhesive

Nature excels in synthesizing advanced protein adhesives under mild condition, utilizing enzyme catalysis to achieve controllable and adjustable cold-set adhesion. To emulate this natural prowess in synthetic protein adhesives (SPAs), which are often hindered by low reactivity, weak controllability, and poor selectivity, we developed a biomimetic-enzyme-catalysis strategy to successfully construct SPAs with cold-set adhesion function via a facile one-pot method. By employing magnesium oxide (MgO) as a catalyst, the resultant adhesive demonstrated enhanced and versatile adhesion capabilities (1.67/0.98 MPa to wood for dry/wet condition, respectively), with controllable and adjustable adhesion by tailoring crosslinked and catalytic sites. Moreover, this design was applicable to various types of crosslinkers and proteins to create more robust cold-set SPAs. The investigation of the catalysis mechanism has revealed that MgO selectively and controllably interacts with adhesive molecules, effectively lowering the energy barrier necessary for successful molecular crosslinks at room temperature. Together with its demonstrated potential in large-scale and long-term applications, our strategy provides a viable pathway for the eco-friendly and scalable production of high-quality cold-set SPAs that rival natural protein adhesives.