Developing antifouling biointerfaces based on bioinspired zwitterionic dopamine through pH-modulated assembly.

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Nanotechnology

Background:

• Synthetic biomaterials in implants often cause protein, cell, and bacteria adsorption, leading to complications like thrombosis and infection.
• Effective surface coatings are crucial for medical devices to prevent nonspecific adsorption and enhance biocompatibility.

Purpose of the Study:

• To develop and evaluate a novel antifouling surface coating for titanium dioxide (TiO2) using a dopamine-conjugated zwitterionic sulfobetaine moiety (SB-DA).
• To investigate the pH-modulated binding mechanism of SB-DA on TiO2 surfaces and assess its antifouling performance.

Main Methods:

• Electrochemical analysis to study SB-DA redox behavior at different pH levels.
• Contact angle goniometry and X-ray photoelectron spectroscopy (XPS) to analyze surface hydration and chemical bonding.
• Quartz crystal microbalance with dissipation (QCM-D) and fluorescence microscopy to evaluate antifouling properties against proteins and bacteria.

Main Results:

• SB-DA exhibited pH-dependent electrochemical behavior, transitioning from reversible at pH 3 to irreversible at pH 8.
• The binding mechanism of SB-DA to TiO2 shifted from hydrogen bonding to bidentate binding with a pH increase from 3 to 8.
• The pH transition approach yielded highly covered and stable SB-DA films with excellent resistance to protein and bacteria adsorption, comparable to traditional zwitterionic coatings.

Conclusions:

• The pH-modulated assembly of SB-DA provides an effective strategy for creating robust antifouling surfaces on TiO2.
• This biologically inspired surface modification demonstrates significant potential for a wide range of biomedical applications.
• The pH transition strategy is applicable to other functional dopamine derivatives for advanced biomaterial development.