Boc‐Protection on L‐DOPA: an Easy Way to Promote Underwater Adhesion

Abstract

The ability of mussels to adhere to underwater surfaces has attracted a lot of attention from the scientific community. As proteins containing L‐DOPA (3,4‐dihydroxyphenyl‐l‐alanine) are involved in their adhesion, a common strategy to synthesize adhesives is the incorporation of this amino acid into other compounds. Herein, we report a study on four compounds of the family of Bocx‐(L‐DOPA)n‐OMe (x = 1–3; n = 1,2), that we prepared through simple synthetic steps. Three of them showed the capability of underwater adhesion: while they are not adhesive in the dry phase, the adhesiveness is triggered when the dried sample is immersed in water or any aqueous solutions. The introduction of protecting groups stabilizes L‐DOPA, preventing the oxidation of the catechol moiety, and enhances the hydrophobicity, helping the removal of water from the surface to bind. These molecules show good adhesiveness, with different properties, so they may be all used as adhesives for different purposes. These outcomes pave the way for new applications for these materials as green and biocompatible adhesives.

Experimental Correlation between Apparent pKa and Gelation Propensity in Amphiphilic Hydrogelators Derived from l-Dopa

“…l -Dihydroxyphenylalanine ( l -Dopa) is a natural amino acid that can be found in several natural structures. Among them, byssus is certainly the natural fiber that is richest in Dopa, as the catechol unit is required to make the adhesive effect needed to anchor the mussels to rocks in the sea. − The presence of multiple interacting sites also makes l -Dopa a suitable building block to prepare a variety of supramolecular materials, ranging from adhesives, to particles, fibers, and gels . This is possible because amino acid and peptide derivatives are able to self-assemble through noncovalent interactions (hydrogen bond, π–π stacking, van der Waals forces, etc.…”

Adhesive Capable of Underwater Adhesion and Wound Hemostasis Prepared Based on Solvent Exchange

“…[ 5 ] In order to solve this problem, researchers have adopted various methods. There are three main methods: 1) drainage: based on hydrophilic and hydrophobic interaction, a material with both hydrophilic and hydrophobic parts is prepared to make the hydrophobic part to drain water and the partial to adhere substrates; [ 6,7 ] 2) solvent exchange: dissolving materials with a water‐soluble solvent such as dimethyl sulfoxide (DMSO), when add water to it, DMSO will gradually dissolves in water and the materials will slowly agglomerate in the mixed solution to form a viscous coacervate due to the increase in the polarity of the solvent; [ 8 ] 3) modifying the mussel mucins and cement proteins (CPs) that are founded by studying the underwater adhesion of marine organisms such as mussels, [ 9–12 ] barnacles, [ 13–15 ] etc.…”