Skip to Content
Merck
  • Control of heterogeneous nucleation and growth kinetics of dopamine-melanin by altering substrate chemistry.

Control of heterogeneous nucleation and growth kinetics of dopamine-melanin by altering substrate chemistry.

Langmuir : the ACS journal of surfaces and colloids (2015-03-06)
Luke Klosterman, John K Riley, Christopher John Bettinger
ABSTRACT

Dopamine-melanin (DM or "polydopamine") can be deposited on virtually any substrate from solution through autoxidation of dopamine. The versatility of this process has allowed surface-mediated assembly of DM for a wide variety of functional coatings. Here we report the impact of well-defined surface chemistries on the nucleation and growth of such films. DM was deposited on silicon dioxide (SiO2) and SiO2 substrates modified with self-assembled monolayers (SAMs) bearing octadecyl (C18), phenethyl, and aminopropyl functional groups. Atomic force microscopy revealed three-dimensional islands whose areal density and surface coverage are lowest on bare SiO2 substrates and highest on the neutral aromatic and aliphatic substrates. Increasing the pH of the solution from 8.2 to 10 dissociates catechol moieties in DM and inhibits adsorption on negatively charged SiO2 substrates. The growth rate of DM films on SAM-modified SiO2 is maximized at pH 9.5 and almost completely abolished at pH 10 because of increased DM solubility. The initial rates of DM adsorption were measured using quartz crystal microbalance with dissipation measurements. The initial adsorption rate is proportional to the nucleation density, which increases as the hydrophobicity of the substrate increases. Taken together, these data provide insight into the rates of heterogeneous nucleation and growth of DM on substrates with well-defined chemistries.

MATERIALS
Product Number
Brand
Product Description

Supelco
Dopamine hydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Sodium bicarbonate, tested according to Ph. Eur.
Supelco
Sodium carbonate, reference material for titrimetry, certified by BAM, >99.5%
Sigma-Aldrich
Trichloroethylene, anhydrous, contains 40 ppm diisopropylamine as stabilizer, ≥99%
Supelco
Trichloroethylene, analytical standard, stabilized with 30 – 50 ppm Diisopropylamine
Sigma-Aldrich
Sodium carbonate, anhydrous, powder, 99.999% trace metals basis
Sigma-Aldrich
Dopamine hydrochloride
Sigma-Aldrich
Sodium carbonate, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium bicarbonate, BioXtra, 99.5-100.5%
Sigma-Aldrich
Sodium carbonate, BioUltra, anhydrous, ≥99.5% (calc. on dry substance, T)
Sigma-Aldrich
Sodium bicarbonate, powder, BioReagent, for molecular biology, suitable for cell culture, suitable for insect cell culture
Sigma-Aldrich
Trichloroethylene, ACS reagent, ≥99.5%
Supelco
Trichloroethylene, Pharmaceutical Secondary Standard; Certified Reference Material
Dopamine hydrochloride, European Pharmacopoeia (EP) Reference Standard
USP
Sodium bicarbonate, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Sodium hydrogencarbonate, −40-+140 mesh, ≥95%
Sigma-Aldrich
Sodium bicarbonate, ReagentPlus®, ≥99.5%, powder
Sigma-Aldrich
Sodium bicarbonate, ACS reagent, ≥99.7%
Sigma-Aldrich
Sodium bicarbonate, anhydrous, free-flowing, Redi-Dri, ReagentPlus®, ≥99.5%
Sigma-Aldrich
Sodium bicarbonate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E500, 99.0-100.5%, powder
Sigma-Aldrich
Sodium carbonate, powder, ≥99.5%, ACS reagent
Sigma-Aldrich
Sodium carbonate, anhydrous, free-flowing, Redi-Dri, ACS reagent, ≥99.5%
Sigma-Aldrich
Sodium carbonate, ReagentPlus®, ≥99.5%
Sigma-Aldrich
Sodium bicarbonate, anhydrous, free-flowing, Redi-Dri, ACS reagent, ≥99.7%
Sigma-Aldrich
Sodium carbonate, ACS reagent, anhydrous, ≥99.5%, powder or granules
Sigma-Aldrich
Sodium carbonate, ACS reagent (primary standard), anhydrous, 99.95-100.05% dry basis
Supelco
Sodium carbonate concentrate, Na2CO3 72 mM in water, IC eluent concentrate (20x) for Metrosep A Supp 7