Polydopamine Coatings in Multifunctional Materials

Polydopamine represents a versatile, bioinspired coating formed by the oxidative self-polymerisation of dopamine under mild alkaline conditions. Its unique combination of catechol and amine functionalities confers strong adhesion to a wide range of substrates, from metals and ceramics to polymers and biological tissues. The resulting thin films, typically a few nanometres to hundreds of nanometres thick, serve as universal primers for further chemical modification, enabling immobilisation of enzymes, metallic nanoparticles or functional polymers. Structurally amorphous yet mechanically robust, polydopamine coatings exhibit metal-chelation, radical scavenging and photothermal properties, while their surface chemistry can be tuned via secondary reactions with nucleophiles. These multifunctional characteristics have led to applications in anti-corrosion protection, antimicrobial surfaces, biosensing interfaces, energy storage electrodes and drug-delivery platforms. Current efforts focus on controlling deposition kinetics, elucidating polymerisation pathways and tailoring film morphology to optimise performance across biomedical, environmental and electronic technologies.

Research from Nature Portfolio

Recent studies have employed high-surface-area halloysite nanotubes to capture intermediate species during polydopamine deposition, revealing that initial oxidative coupling of dopaminechrome yields linear polycatecholamine oligomers, followed by cyclisation into indole-based segments, with tris(hydroxymethyl)aminomethane incorporated into early oligomers. This mechanistic insight clarifies the stepwise growth of adhesive films. Earlier foundational work demonstrated that mechanical agitation during deposition produces roughened polydopamine layers with enhanced antibacterial efficacy against both Gram-positive and Gram-negative pathogens, independent of supporting substrate or subsequent sterilisation. In addition, electrochemical co-polymerisation of dopamine and pyrrole onto electrode surfaces has been shown to produce conductive, strongly adherent composite films, markedly reducing interfacial impedance and offering a facile route to biosensor and rechargeable battery electrodes.

Polydopamine Coatings in Multifunctional Materials publication trend

The graph below shows the total number of articles in polydopamine coatings in multifunctional materials across all publications each year (not limited to Nature Index journals).

Technical terms

Catechol: A benzene diol structure bearing two adjacent hydroxyl groups that mediates strong wet adhesion and metal chelation.

Quinone: The oxidised form of catechol that readily undergoes nucleophilic addition, enabling cross-linking reactions during film growth.

Oligomer: A low-molecular-weight polymer consisting of a few repeating monomer units, often serving as intermediates in polydopamine formation.

5,6-Dihydroxyindole (DHI): A cyclised dopamine derivative whose incorporation into the polymer network significantly enhances adhesive strength.

Oxidative self-polymerisation: A spontaneous process in which dopamine oxidises to quinone species and subsequently links through covalent and non-covalent interactions to form a polymeric film.

References

1. Polydopamine Nanomaterials: Recent Advances in Synthesis Methods and Applications. Frontiers in Bioengineering and Biotechnology (2018).
2. Strong Antibacterial Polydopamine Coatings Prepared by a Shaking-assisted Method. Scientific Reports (2016).
3. New insights in polydopamine formation via surface adsorption. Nature Communications (2023).
4. Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films. Scientific Reports (2016).
5. The Chemistry of Polydopamine Film Formation: The Amine-Quinone Interplay. Biomimetics (2018).
6. Revisiting the adhesion mechanism of mussel-inspired chemistry. Chemical Science (2022).