Engineering a Thermally Activatable SpyCatcher/SpyTag Protein Ligation for Injectable and In Situ-Forming Hydrogels.

Area of Science:

• Biomaterials Science
• Chemical Engineering
• Molecular Biology

Background:

• Injectable hydrogels are crucial for tissue engineering and drug delivery.
• Current hydrogels face challenges in balancing gelation speed, mechanical strength, and cytocompatibility.

Purpose of the Study:

• To develop a novel thermally activatable SpyCatcher/SpyTag (TASpy) system for rapid in situ hydrogel formation.
• To create robust, injectable protein hydrogels with improved properties.

Main Methods:

• Engineered a thermally activatable SpyCatcher (TASpyC) by fusing SpyCatcher with a non-reactive SpyTag mutant.
• Utilized the CnaB2 domain inspiration for temperature-dependent unfolding and covalent binding.
• Investigated hydrogel properties including gelation kinetics, mechanical strength, cell encapsulation, and in vivo performance.

Main Results:

• The TASpy system demonstrated rapid chemical crosslinking at physiological temperature (37°C).
• Achieved enhanced mechanical properties, improved cell encapsulation, and accelerated gelation upon heating.
• TASpy hydrogels exhibited high cell viability, excellent in vivo retention, and biocompatibility, with subcutaneous injections solidifying within minutes.

Conclusions:

• The TASpy system offers a promising approach for developing advanced injectable protein hydrogels.
• This technology addresses key limitations in current hydrogel systems for biomedical applications.
• TASpy hydrogels show significant potential for tissue engineering and drug delivery applications due to their rapid formation, mechanical robustness, and biocompatibility.