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

The fabrication of hybrid protein-Cu3(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 ≈1.8-fold increase in catalytic activity compared to free laccase under diffusion control, which is further enhanced by ≈ 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 coating in continuous flow processing. The results demonstrate the utility of the VFD microfluidic platform, further highlighting its ability to control chemical and enzymatic processes.

Continuous flow vortex fluidic-mediated exfoliation and fragmentation of two-dimensional MXene.

MXene (Ti2CT x ) is exfoliated in a vortex fluidic device (VFD), as a thin film microfluidic platform, under continuous flow conditions, down to ca 3 nm thin multi-layered two-dimensional (2D) material, as determined using AFM. The optimized process, under an inert atmosphere of nitrogen to avoid oxidation of the material, was established by systematically exploring the operating parameters of the VFD, along with the concentration of the dispersed starting material and the choice of solvent, which was a 1 : 1 mixture of isopropyl alcohol and water. There is also some fragmentation of the 2D material into nanoparticles ca 68 nm in diameter.

Vortex fluidic mediated synthesis of polysulfone.

Polysulfone (PSF) was prepared under high shear in a vortex fluidic device (VFD) operating in confined mode, and its properties compared with that prepared using batch processing. This involved reacting the pre-prepared disodium salt of bisphenol A (BPA) with a 4,4'-dihalodiphenylsulfone under anhydrous conditions. Scanning electron microscopy (SEM) established that in the thin film microfluidic platform, the PSF particles are sheet-like, for short reaction times, and fibrous for long reaction times, in contrast to spherical like particles for the polymer prepared using the conventional batch synthesis. The operating parameters of the VFD (rotational speed of the glass tube, its tilt angle and temperature) were systematically varied for establishing their effect on the molecular weight (M w), glass transition temperature (T g) and decomposition temperature, featuring gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) respectively. The optimal VFD prepared PSF was obtained at 6000 rpm rotational speed, 45° tilt angle and 160 °C, for 1 h of processing with M w ∼10 000 g mol-1, T g ∼158 °C and decomposition temperature ∼530 °C, which is comparable to the conventionally prepared PSF.

Continuous flow synthesis of phosphate binding h-BN@magnetite hybrid material.

Hexagonal boron nitride (h-BN) is rendered magnetically responsive in aqueous media by binding superparamagnetic magnetite nanoparticles 8.5-18.5 nm in diameter on the surface. The composite material was generated under continuous flow in water in a dynamic thin film in a vortex fluidic device (VFD) with the source of iron generated by laser ablation of a pure iron metal target in the air above the liquid using a Nd:YAG pulsed laser operating at 1064 nm and 360 mJ. Optimum operating parameters of the VFD were a rotational speed of 7.5k rpm for the 20 mm OD (17.5 mm ID) borosilicate glass tube inclined at 45 degrees, with a h-BN concentration at 0.1 mg mL-1, delivered at 1.0 mL min-1 using a magnetically stirred syringe to keep the h-BN uniformly dispersed in water prior to injection into the base of the rapidly rotating tube. The resulting composite material, containing 5.75% weight of iron, exhibited high phosphate ion adsorption capacity, up to 171.2 mg PO4 3- per gram Fe, which was preserved on recycling the material five times.