Coupling two enzymes into a tandem nanoreactor utilizing a hierarchically structured MOF.

Area of Science:

• Materials Science
• Nanotechnology
• Biocatalysis

Background:

• Enzyme immobilization is crucial for developing efficient biocatalysts.
• Hierarchical porous materials offer unique environments for enzyme encapsulation.
• Tandem nanoreactors can improve catalytic efficiency by confining sequential reactions.

Purpose of the Study:

• To develop a hierarchical porous metal-organic framework (MOF) for creating a tandem nanoreactor.
• To investigate the controlled encapsulation of two distinct enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP).
• To evaluate the catalytic performance and stability of the enzyme-loaded nanoreactor.

Main Methods:

• Synthesis of a hierarchical porous MOF (PCN-888) with defined cavity sizes.
• Stepwise encapsulation of GOx and HRP into specific cavities of PCN-888.
• Characterization of the nanoreactor's structure and enzyme loading.
• Assessment of catalytic activity, enzyme leaching, and stability against digestion.

Main Results:

• PCN-888 possesses three distinct cavities (6.2 nm, 5.0 nm, 2.0 nm) enabling selective enzyme accommodation.
• A specific sequential encapsulation order (GOx first, then HRP) was required.
• The resulting tandem nanoreactor exhibited excellent catalytic performance with minimal enzyme leaching.
• The nanoreactor maintained catalytic activity over multiple cycles and protected enzymes from trypsin digestion.

Conclusions:

• Hierarchical MOFs like PCN-888 can be designed for precise enzyme co-localization in tandem nanoreactors.
• The stepwise encapsulation strategy ensures efficient enzyme coupling and enhanced biocatalysis.
• PCN-888-based nanoreactors offer superior stability and protection for encapsulated enzymes, suggesting potential for in vitro and in vivo applications.