Inspired by mussels adhering to wet rocks, Nano and Advanced Materials Institute (NAMI) has invented a catechol-grafted silicone sealant with excellent bonds on hard-to-attach surfaces. The unique catechol groups in the silicone sealant system designed by NAMI can repel water molecules and form strong chemical covalent and physical electrostatic bonds on wet surfaces. In particular, the adhesive strength on the wet substrate of NAMI’s bio-inspired silicone sealant can achieve over 0.5 MPa, while commercial silicone sealant performance is less than 0.15 MPa. NAMI’s bio-inspired silicone sealant also has good flexibility with a movement capability of ±50%, good durability, and long-term resistance to ultraviolet radiation, high and low temperatures, and outdoor exposure.