Surface-facilitated formation of polydopamine and its implications in melanogenesis

Abstract

This manuscript examines influences of differently functionalized surfaces on the formation of solution-dispersed polydopamine (pDA). Glass vials functionalized with different functional groups provided a set of conditions with which the relationship between the area of active surface and the rate of pDA formation could be sys-tematically studied. The results suggest that charged and polar surfaces accelerate pDA formation in solution, with the effect of-NH2 surfaces being exceptionally strong. In the vials, pDA formed as both forms of dispersions in solution and films at solid-liquid interface. Further analyses confirmed that both forms of pDA formed with-NH2 surfaces were chemically similar to conventional pDA synthesized without help of functional surfaces. Among short peptide-based amyloid fibers with defined surface functional groups, and those displaying lysines (-NH2) greatly accelerated the formation of pDA, consistent with the results of-NH2-functionalized vials. The results suggest that pDA formation may be facilitated by surface functional groups of solid-liquid interfaces, and have implications for the overlooked roles of amyloid fibers in biological melanogenesis.