Bioinspired catechol-terminated self-assembled monolayers with enhanced adhesion properties.

Area of Science:

• Materials Science
• Surface Chemistry
• Biomimetics

Background:

• The adhesive properties of mussel proteins are crucial for marine adhesion.
• The catechol moiety is key to mussel adhesion, but its precise role in synthetic materials remains unclear.
• Self-assembled monolayers (SAMs) offer a model system to study molecular interactions.

Purpose of the Study:

• To investigate the adhesive properties of catechol-terminated SAMs on gold substrates.
• To compare the adhesion of SAMs with polydopamine coatings.
• To explore the influence of catechol orientation and SAM homogeneity on adhesion.

Main Methods:

• Fabrication of catechol-terminated SAMs on epitaxial gold substrates.
• Spectroscopic confirmation of catechol orientation and absence of o-quinones.
• Atomic force microscopy (AFM) for measuring local adhesion forces.
• Molecular dynamics simulations and AFM lithography to study SAM formation.

Main Results:

• SAMs with upward-facing catechols demonstrated an average adhesion force of 45 nN, exceeding that of polydopamine.
• The SAMs exhibited superior reproducibility and less statistical dispersion in adhesion forces.
• Catechol-terminated SAMs were successfully formed on rough gold surfaces, enabling magnetic nanoparticle assembly.

Conclusions:

• Upward-facing catechols in SAMs provide a robust and reproducible adhesive interface.
• SAMs offer a more controlled system than polydopamine for studying catechol-mediated adhesion.
• This model system advances the understanding of mussel-inspired adhesion for material applications.