Mechanically robust, negative-swelling, mussel-inspired tissue adhesives

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surgical Innovation

Background:

• Synthetic polymer hydrogels often swell excessively in physiological conditions, leading to mechanical failure and adverse medical outcomes.
• Existing hydrogel adhesives and sealants require improved mechanical strength and controlled swelling for effective clinical use.

Purpose of the Study:

• To synthesize and characterize mechanically robust, zero- or negative-swelling surgical adhesives inspired by mussel adhesive proteins.
• To develop a novel approach for controlling hydrogel swelling and enhancing mechanical properties for biomedical applications.

Main Methods:

• Synthesis of catechol-modified amphiphilic poly(propylene oxide)-poly(ethylene oxide) block copolymers.
• Characterization of gel formation, swelling behavior, bulk mechanical properties, and tissue adhesion.
• Utilizing catechol oxidation for cross-linking and thermal transitions for mechanical toughening.

Main Results:

• Achieved mechanically tough hydrogels with zero or negative swelling under physiological conditions.
• Demonstrated rapid chemical cross-linking via catechol oxidation at low temperatures.
• Observed volumetric reduction and mechanical toughening upon warming to physiological temperatures due to hydrophobic transitions.

Conclusions:

• Developed a general strategy for creating mechanically robust, low-swelling hydrogel adhesives using mussel-inspired chemistry.
• The approach offers a promising method to enhance the performance of polymer hydrogels in medical contexts, minimizing complications associated with swelling.
• This adaptable strategy can be applied to various thermally sensitive block copolymers and cross-linking methods for improved surgical sealants and adhesives.