Bioinspired Pseudozwitterionic Hydrogels with Bioactive Enzyme Immobilization via pH-Responsive Regulation.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surface Science

Background:

• Hydrogels are crucial in biomedical applications, but minimizing nonspecific protein adsorption is essential for their function.
• Functionalizing hydrogels with biomacromolecules can significantly expand their biotechnological utility.
• Developing low-fouling materials that allow selective protein immobilization is a key challenge.

Purpose of the Study:

• To prepare and characterize novel low-fouling hydrogel polymers for selective protein immobilization.
• To investigate the relationship between hydrogel composition and antifouling properties.
• To explore the pH-responsive protein adsorption capabilities of the developed hydrogels.

Main Methods:

• Hydrogels were synthesized via free radical polymerization using varying ratios of 2-carboxyethyl acrylate (CA) and 2-dimethylaminoethyl methacrylate (DMAEMA) monomers, cross-linked with N, N-methylene-bis-acrylamide (NMBA).
• X-ray photoelectron spectroscopy (XPS) and dynamic laser scattering were employed to determine actual polymer ratios and surface charge.
• Antifouling properties, hemocompatibility, and protein immobilization were assessed.

Main Results:

• A hydrogel with a CA:DMAEMA ratio of 6:4 (C6D4) exhibited a near-neutral surface charge and equivalent monomer incorporation.
• This C6D4 hydrogel demonstrated excellent antifouling characteristics, including low blood cell adhesion and platelet deactivation.
• The hydrogel showed pH-responsive protein adsorption, successfully immobilizing lipase while maintaining low fouling.

Conclusions:

• A mixed-charge, nonfouling, pseudozwitterionic hydrogel was successfully prepared.
• The hydrogel's pH-responsive adsorption capability offers potential for advanced applications.
• This material shows promise for biocompatible tissue engineering matrices and membrane enzyme reactors.