Calcium-Mediated Control of Polydopamine Film Oxidation and Iron Chelation

Abstract

The facile preparation of conformal polydopamine (PDA) films on broad classes of materials has prompted extensive research into a wide variety of potential applications for PDA. The constituent molecular species in PDA exhibit diverse chemical moieties, and therefore highly variable properties of PDA-based devices may evolve with post-processing conditions. Here we report the use of redox-inactive cations for oxidative post-processing of deposited PDA films. PDA films incubated in alkaline CaCl2 solutions exhibit accelerated oxidative evolution in a dose-dependent manner. PDA films incubated in CaCl2 solutions exhibit 53% of the oxidative charge transfer compared to pristine PDA films. Carboxylic acid groups generated from the oxidation process lower the isoelectric point of PDA films from pH = 4.0 ± 0.2 to pH = 3.1 ± 0.3. PDA films exposed to CaCl2 solutions during post-processing also enhance Fe2+/Fe3+ chelation compared to pristine PDA films. These data illustrate that the molecular heterogeneity and non-equilibrium character of as-deposited PDA films afford control over the final composition by choosing post-processing conditions, but also demands forethought into how the performance of PDA-incorporated devices may change over time in salt solutions.

Influence of polydopamine-mediated surface modification on oxygen-release capacity of haemoglobin-based oxygen carriers

“…It should be noted that elevation of the mass ratios of DA/Hb can accelerate the deposition of PDA on the surface, leading to greater film thickness. However, this can also result in aggregation of the nanoparticles [33]. Therefore, the mass ratio of DA/Hb should be adjusted appropriately.…”

Natural melanin pigments and their interfaces with metal ions and oxides: emerging concepts and technologies

“…Nevertheless, promising results have been obtained with synthetic melanin-like polymers, e.g., polydopamine. [10,103] L-dopa [43,55] Natural (Sepia, [48,56] bovine eye [41] ) 5,6-Dihydroxyindole (DHI)-melanin (QI) [57] Mg 2+ Natural (Sepia [58] ) Natural (bovine eye, [41,45] Sepia, [48,56,59] squid [60] ), dopa-melanin [45] Ca 2+ Natural (bovine eye, [41,45] Sepia, [48,56,59,61] squid [60] ), dopa-melanin [45] Fe 3+ Natural (Sepia, [56,59,62] human hair, [63] black rabbit hair [64] ), neuromelanin, [65][66][67] dopa, [68][69][70] catechols, [71] polydopamine, [72][73][74] DHI-melanin, [63] melanin from cys-dopamine, [75] diethylaminedopamine-melanin [74] Neuromelanin, [76] dopa-melanin, [74] natural (Sepia), [74] diethylamine-dopaminemelanin [74] Natural (Sepia), …”

Post translational modification-assisted cancer immunotherapy for effective breast cancer treatment

“…Despite the overall negative charge of the serum proteins, random adsorption of serum proteins on negatively charged nanoparticles due to weak electrostatic pull initiated by the multiple positive sites 28 of serum proteins has been reported previously. 29,30 The zeta potential of DMSN is less negative than that of TiDMSN due to the extensive availability of hydroxyl groups on both silica and polydopamine, 31,32 leading to less repulsion with negatively charged serum proteins, more aggregation of nanoparticles, and possibly more non-specic protein adsorption in comparison with TiDMSN.…”