Characterization And Process Simulation Of Catalase-based Nanoparticles Prepared By Shear Stress Alone

Catalase is a therapeutic enzyme which protects cells from oxidative injuries via catalyzing the degradation of ROS. It plays a significant role in treatment for many diseases. However, it carries risks of inactivation and rapid degradation when it is used in practical bioprocess, such as delivery in vivo, which limits its clinical use. To overcome the issue, catalase-only nanoparticles were prepared using a method with shear stress alone. Catalase nanoparticles prepared using solution concentration of 0.2 mg/m L and treated with shear rate of 217 s-1 for 5 minutes turned out to be uniform with a particle size of 182±8.5 nm and the relative activity of 90%. With the spectroscopic investigation, it was found that the conformational changes of catalase caused by shear alone were minor. The activity of catalase nanoparticles decreased only by 20% in the simulated intestinal fluid containing ?-chymotrypsin during 4-h incubation at 37 °C, implying that the nanogranulated catalase was more stable and had better ability of resisting the degradation of proteases.In the second part, computational fluid dynamics simulation and population balance were used to study the theoretic foundation for the shear-alone method and the particle size prediction. Information such as velocity field, shear stress field could be obtained using CFD. It was found that areas around blenders were full of high speed and energy, while dead zone existed at surface and near walls; Population balance coupled with CFD was applied for simulating the formation of catalase nanoparticle and predicting the time-evolution Sauter particle diameter, which stabled at 208 nm under the shear rate of 217 s-1. Compared to the experimental result of 182 nm, the CFD-PBM had good consistency.Overall, catalase-only nanoparticles and the shear-alone preparation method offered a great potential to stabilize enzymes for various pharmaceutical applications, and the CFD and CFD-PBM simulation offered a lot of effective information of theoretical basis, device design and scaled-up production.