Vortex Fluidic-Mediated Fabrication of Fast Gelated Silica Hydrogels with Embedded Laccase Nanoflowers for Real-Time Biosensing under Flow

The fabrication of hybrid protein-Cu-3(PO4)(2) nanoflowers (NFs) via an intermediate toroidal structure is dramatically accelerated under shear using a vortex fluidic device (VFD), which possesses a rapidly rotating angled tube. As-prepared laccase NFs (LNFs) exhibit approximate to 1.8-fold increase in catalytic activity compared to free laccase under diffusion control, which is further enhanced by approximate to 2.9-fold for the catalysis under shear in the VFD. A new LNF immobilization platform, LNF@silica incorporated in a VFD tube, was subsequently developed by mixing the LNFs for 15 min with silica hydrogel resulting in gelation along the VFD tube surface. The resulting LNFs@silica coating is highly stable and reusable, which allows a dramatic 16-fold enhancement in catalytic rates relative to LNF@silica inside glass vials. Ultraviolet-visible spectroscopy-based real-time monitoring within the LNFs@silica-coated tube reveals good stability of the flow processing. The results demonstrate the utility of the VFD microfluidic platform, further highlighting its ability to control chemical and enzymatic processes.