Direct Evidence for the Polymeric Nature of Polydopamine

Abstract

Inspired by the adhesive proteins of mussels, polydopamine (pDA) has emerged as one of the most widely employed materials for surface functionalization. Despite numerous attempts at characterization, little consensus has emerged regardingw hether pDAi sacovalent polymer or anoncovalent aggregate of low molecular weight species.Here, we employed single-molecule force spectroscopy( SMFS) to characterize pDAfilms.Retraction of apDA-coated cantilever from an oxide surface shows the characteristic features of apolymer with contour lengths of up to 200 nm. pDApolymers are generally weakly bound to the surface through mucho f their contour length, with occasional "sticky" points.O ur findings represent the first direct evidence for the polymeric nature of pDAand provideafoundation upon which to better understand and tailor its physicochemical properties.

Cooperativity of Catechols and Amines in High‐Performance Dry/Wet Adhesives

“…[19] Single molecule force spectroscopy (SMFS) is another powerful AFM-based characterization method which is well suited to investigate and quantitively measure the strength of chemical bonds as well as adhesive interactions acting between molecules and surfaces. [20] This technique has been widely used in the past for studying the adhesion of mussel-inspired peptides and polymers and advances have been summarized in ar ecent review by Li et al [5a] SMFS measurements are complementary to the CPS experiments and when combined together can provide am ore comprehensive picture of the molecular basis underlying adhesive and cohesive properties of materials.Inthe present work, we utilized both SMFS and CPS techniques to study adhesive performance of PSA polymers to decouple cohesive contributions from interfacial adhesive interactions acting between polymer chains and the surface.…”

Chirally Twisted Ultrathin Polydopamine Nanoribbons: Synthesis and Spontaneous Assembly of Silver Nanoparticles on Them

“…[6] However,t he exact ensuing reactionp athways leadingt oP DA and even the chemical structure of the polymerized product is not established, even though the polymeric natureo fP DA wasd emonstrated recently. [7,8] Nonetheless, PDA has attracted intense research attentioni nt he past two decades for creating bioinspired tissue adhesives and antifouling coatings for aw ide variety of surfaces, and as am aterial with strong photo-thermalc onversiona bilities, as well as organocatalyst for aldol reaction. [9][10][11][12] PDA sphereswere also utilized as templates for convenient synthesis of MnO 2 hollows pheres and core/shell nanostructureso fP DA/Fe 3 O 4 and PDA/Ag.…”

Functional Macromolecule‐Enabled Colloidal Synthesis: From Nanoparticle Engineering to Multifunctionality

“…In brief, the catechol groups of dopamine are converted to corresponding dopamine quinone first, as a result of the oxidation of the catechol group in an alkaline environment, followed by sequential intramolecular cyclization, catechol oxidation‐induced isomerization, and oligomerization, giving rise to the crosslinked PDA. It is believed that the repeated oxidation of the built‐in catechol groups of dopamine and intermediates plays a vital role in the formation of PDA . The presence of abundant catechol functionalities in PDA imparts a strong coordination ability with multivalent metal ions (e.g., Fe 3+ , Zn 2+ , and Cu 2+ ) and reducing activity towards noble metal ions (e.g., Ag + ) during or after the formation of PDA .…”