Spatial Confinement of Enzyme and Nanozyme in Silica-Based Hollow Microreactors

Area of Science:

• Biomaterials Science
• Nanotechnology
• Catalysis

Background:

• Enzyme and nanozyme encapsulation in microreactors aims to enhance selectivity and activity.
• Spatial confinement strategies are crucial for optimizing nanozyme performance.

Purpose of the Study:

• To develop a facile method for encapsulating glucose oxidase (GOx) and Fe3O4-PEI nanozymes within hybrid microreactors.
• To investigate the effect of microreactor shape and confinement on the catalytic activity of encapsulated enzymes and nanozymes.

Main Methods:

• Hybrid microreactors were fabricated using silica nanoparticle assembly on removable calcium carbonate cores.
• Tuning calcium carbonate shape and phase generated hollow microspheres (GOx-Fe3O4@SHS) and microcubes (GOx-Fe3O4@SHC).
• Biomimetic cascade catalysis was employed to assess the activity of encapsulated GOx and Fe3O4-PEI.

Main Results:

• The encapsulated GOx and Fe3O4-PEI demonstrated a cascade reaction, catalyzing glucose oxidation and subsequent substrate oxidation.
• Hollow microspheres (GOx-Fe3O4@SHS) exhibited 14 times higher peroxidase-like activity compared to hollow microcubes (GOx-Fe3O4@SHC).
• A fivefold increase in the catalytic constant (kcat) was observed for Fe3O4-PEI confined in microspheres compared to free components in solution.

Conclusions:

• Spatial confinement within hybrid microreactors significantly enhances the tandem catalytic activity of enzymes and nanozymes.
• The shape of the microreactor (microspheres vs. microcubes) influences nanozyme loading and overall catalytic efficiency.
• This approach offers a promising strategy for designing high-performance nanozyme-based catalytic systems.