The study investigates the single-molecule adhesive properties of 3,4-dihydroxy-L-phenylalanine (dopa) on both inorganic and organic surfaces. Dopamine, a key component of mussel adhesive proteins, is found to form strong, reversible, noncovalent interactions with wet metal oxide surfaces, with a bond dissociation energy of approximately 805 pN. This interaction is significantly stronger than hydrogen bond formation but weaker than covalent bonds. Oxidation of dopa, which occurs during the curing of mussel glue, reduces the strength of the interaction with metal oxides but enhances the formation of high-strength, irreversible covalent bonds with organic surfaces. The results suggest that dopa's unique chemical versatility allows it to adhere to a wide range of substrates, from inorganic to organic materials, by exploiting both high-strength coordination bonds and covalent bonding mechanisms.The study investigates the single-molecule adhesive properties of 3,4-dihydroxy-L-phenylalanine (dopa) on both inorganic and organic surfaces. Dopamine, a key component of mussel adhesive proteins, is found to form strong, reversible, noncovalent interactions with wet metal oxide surfaces, with a bond dissociation energy of approximately 805 pN. This interaction is significantly stronger than hydrogen bond formation but weaker than covalent bonds. Oxidation of dopa, which occurs during the curing of mussel glue, reduces the strength of the interaction with metal oxides but enhances the formation of high-strength, irreversible covalent bonds with organic surfaces. The results suggest that dopa's unique chemical versatility allows it to adhere to a wide range of substrates, from inorganic to organic materials, by exploiting both high-strength coordination bonds and covalent bonding mechanisms.