Water-Soluble Ionic Metal-Organic Polyhedra as a Versatile Platform for Enzyme Bio-immobilization

Area of Science:

• Materials Science
• Biotechnology
• Nanotechnology

Background:

• Metal-organic polyhedra (MOPs) are promising building blocks for porous materials.
• Low stability and water solubility of MOPs limit their biological applications.
• Developing MOPs compatible with biological systems is crucial for advanced applications.

Purpose of the Study:

• To synthesize novel MOPs with enhanced stability and solubility in aqueous environments.
• To investigate the spontaneous assembly of these MOPs with proteins.
• To evaluate the impact of MOP-protein assemblies on enzyme activity and recyclability.

Main Methods:

• Synthesis of anionic and cationic metal-organic polyhedra (MOPs).
• Mixing MOPs with proteins, including bovine serum albumin (BSA), catalase, and cytochrome c, in aqueous solutions.
• Characterization of MOP-protein assemblies formed under varying conditions.
• Assessment of retained catalytic activity and recyclability of immobilized enzymes.

Main Results:

• Novel ionic MOPs were successfully prepared, exhibiting high protein affinity and aqueous stability.
• Spontaneous formation of MOP-protein assemblies was observed, forming colloidal or precipitated states.
• Enzymes (catalase and cytochrome c) retained high catalytic activity within MOP assemblies.
• Co-immobilization of cytochrome c with charged MOPs led to a significant 44-fold increase in catalytic activity.
• Recyclability of the immobilized enzymes was demonstrated.

Conclusions:

• Ionic MOPs provide a versatile platform for creating stable, functional protein assemblies in aqueous media.
• This approach overcomes previous limitations of MOPs in biological applications.
• The enhanced catalytic activity and recyclability of enzymes in MOP-protein assemblies open new avenues for biocatalysis and biotechnology.