Tuning Pore Microenvironments in Covalent Organic Frameworks for Controlled Enzyme Loading and Release

Area of Science:

• Materials Science
• Chemical Engineering
• Biotechnology

Background:

• Covalent Organic Frameworks (COFs) offer tunable pore environments for enzyme delivery.
• The influence of COF pore microenvironments on enzyme loading and release kinetics is not well understood.

Purpose of the Study:

• To investigate the impact of COF pore microenvironment characteristics on enzyme loading, release, and activity.
• To establish design principles for COF-based enzyme delivery systems.

Main Methods:

• Synthesis of TPE-based imine-linked COFs using varying dialdehyde linkers to create distinct pore environments.
• Systematic investigation of papain loading, release, and activity in different COF models.
• In situ FTIR spectroscopy to probe enzyme-framework interactions during loading.

Main Results:

• Hydrophobic COFs showed lower enzyme loading, faster release, and reduced activity.
• Hydrophilic COFs demonstrated efficient enzyme loading, slow release, and slightly lower retained activity.
• In situ FTIR provided molecular-level evidence of microenvironment-governed enzyme behavior.

Conclusions:

• The pore microenvironment of COFs significantly regulates enzyme loading, release, and retained activity.
• Rational design of COFs based on pore hydrophobicity/hydrophilicity is crucial for optimizing enzyme delivery and biocatalysis.
• This study provides key insights for developing advanced COF-based protein delivery and biocatalytic platforms.