Adhesion and Cohesion Differences between Catechol- and Pyrogallol-Functionalized Chitosan.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surface Science

Background:

• Marine-inspired phenolic compounds are crucial for developing effective biomedical adhesives for wet conditions.
• Understanding the impact of varying hydroxyl group numbers in catechol and pyrogallol moieties on adhesion and cohesion is limited.

Purpose of the Study:

• To investigate the effect of catechol and pyrogallol functionalization on chitosan's adhesive and cohesive properties.
• To compare the interaction energies of chitosan-catechol (CS-CA) and chitosan-pyrogallol (CS-GA) using surface forces apparatus (SFA).

Main Methods:

• Functionalization of chitosan backbone with catechol and pyrogallol at similar modification rates.
• Utilizing surface forces apparatus (SFA) to measure interaction energies.
• Comparative analysis of chitosan, CS-CA, and CS-GA at pH 7.4.

Main Results:

• Phenolic moieties reduced chitosan chain rigidity and increased solubility, enhancing cohesion and adhesion for both CS-CA and CS-GA compared to chitosan.
• Chitosan-pyrogallol (CS-GA) exhibited superior cohesion and adhesion over chitosan-catechol (CS-CA) due to the additional hydroxyl group in pyrogallol providing enhanced interaction.
• Both modified chitosans demonstrated improved performance as underwater biomedical adhesives.

Conclusions:

• The study provides critical insights into the structure-property relationships of chitosan derivatives with phenolic moieties.
• Findings will aid in the rational design and development of advanced chitosan-based biomedical adhesives with tunable underwater adhesion.
• Pyrogallol functionalization offers a promising strategy for enhancing the performance of biomedical adhesives.