The Chemistry of Polydopamine Film Formation: The Amine-Quinone Interplay
Abstract
Despite extensive investigations over the past decade, the chemical basis of the extraordinary underwater adhesion properties of polydopamine (PDA) has remained not entirely understood. The bulk of evidence points to PDA wet adhesion as a complex process based on film deposition, and growth in which primary amine groups, besides catechol moieties, play a central role. However, the detailed interplay of chemical interactions underlying the dynamics of film formation has not yet been elucidated. Herein, we report the results of a series of experiments showing that coating formation from dopamine at pH 9.0 in carbonate buffer: (a) Requires high dopamine concentrations (>1 mM); (b) is due to species produced in the early stages of dopamine autoxidation; (c) is accelerated by equimolar amounts of periodate causing fast conversion to the o-quinone; and (d) is enhanced by the addition of hexamethylenediamine (HMDA) and other long chain aliphatic amines even at low dopamine concentrations (<1 mM). It is proposed that concentration-dependent PDA film formation reflects the competition between intermolecular amine-quinone condensation processes, leading to adhesive cross-linked oligomer structures, and the intramolecular cyclization route forming little adhesive 5,6-dihydroxyindole (DHI) units. Film growth would then be sustained by dopamine and other soluble species that can be adsorbed on the surface.
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BibTeX
@article{alfieri2026chemistry,
title = {{The Chemistry of Polydopamine Film Formation: The Amine-Quinone Interplay}},
author = {Maria Laura Alfieri and Lucia Panzella and Stefano Luigi Oscurato and Marcella Salvatore and Roberto Avolio and Maria Emanuela Errico and Pasqualino Maddalena and Alessandra Napolitano and Marco d'Ischia},
journal = {Biomimetics},
year = {2026},
month = oct,
doi = {10.3390/biomimetics3030026},
url = {https://hal.science/hal-05789742v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - The Chemistry of Polydopamine Film Formation: The Amine-Quinone Interplay
AU - Maria Laura Alfieri
AU - Lucia Panzella
AU - Stefano Luigi Oscurato
AU - Marcella Salvatore
AU - Roberto Avolio
AU - Maria Emanuela Errico
AU - Pasqualino Maddalena
AU - Alessandra Napolitano
AU - Marco d'Ischia
PY - 2026
DA - 2026/10/09
JO - Biomimetics
DO - 10.3390/biomimetics3030026
UR - https://hal.science/hal-05789742v1
AB - Despite extensive investigations over the past decade, the chemical basis of the extraordinary underwater adhesion properties of polydopamine (PDA) has remained not entirely understood. The bulk of evidence points to PDA wet adhesion as a complex process based on film deposition, and growth in which primary amine groups, besides catechol moieties, play a central role. However, the detailed interplay of chemical interactions underlying the dynamics of film formation has not yet been elucidated. Herein, we report the results of a series of experiments showing that coating formation from dopamine at pH 9.0 in carbonate buffer: (a) Requires high dopamine concentrations (>1 mM); (b) is due to species produced in the early stages of dopamine autoxidation; (c) is accelerated by equimolar amounts of periodate causing fast conversion to the o-quinone; and (d) is enhanced by the addition of hexamethylenediamine (HMDA) and other long chain aliphatic amines even at low dopamine concentrations (<1 mM). It is proposed that concentration-dependent PDA film formation reflects the competition between intermolecular amine-quinone condensation processes, leading to adhesive cross-linked oligomer structures, and the intramolecular cyclization route forming little adhesive 5,6-dihydroxyindole (DHI) units. Film growth would then be sustained by dopamine and other soluble species that can be adsorbed on the surface.
SN - 2313-7673
ER -