Dopa/Catechol-Tethered Polymers: Bioadhesives and Biomimetic Adhesive Materials

AbstractHow does man dare to accept nature's challenges? A myriad of natural products with stunning structures and impressive properties fashion the research platforms of scientists, particularly the chemists and biologists. Indeed, research work undertaken by the latter scientists has unveiled concealed nature's mysteries. Of these mysteries, nature provides us with unusual adhesives in the form of L-DOPA-containing proteins, existing within the mussel feet and commonly called mussel foot proteins (fps). The uniqueness of these bioadhesives resides in their adhering performance to all kinds of surfaces and, more astonishing, under a wet environment. Up to six fps for Mytilus species (Mfps) were identified with varying extents of DOPA content. Improved adhesion performance was even observed for the recombinant Mfps expressed in Escherichia coli. Amine and catechol functionalities are crucial moieties and do play a synergetic effect for such adhesion. In addition, the in vivo crosslinking generated via an oxidative process of catechol units of DOPA to o-quinone groups at marine pH (8.5), takes part into this adhesion occurrence. In vitro crosslinking was achieved with oxidizing agents such as periodate ion and Fe(III), resulting in oxidative crosslinking (covalent crosslinking) and coordinative one (non-covalent crosslinking), respectively. To delve into the enigmatic phenomenon and unravel the chemistry behind, scientists strive to experiment their adhesive ability to substrata of different chemical natures, to make synthetic analogues, that is, bioinspired mussel adhesives, and apply the same work-up. Catechol and its derivatives such as DOPA and dopamine were either polymerized under simulated natural conditions or attached to skeletons of several synthetic polymers and biopolymers. The ongoing thus-biased research has now opened new avenues in biomedicals, hydrogels applications, antifouling processes, and nanotechnology. As friendly operation is greatly coveted, one promising fact is the surgical suture with such bioadhesive and the making of self-healing related materials.Keywords: AntifoulingbioadhesivescatecholDOPAhydrogelsmussels