Ruijie’s postdoctoral and doctoral research is focused on porous materials, such as membranes and depth filters, for liposome sterile filtration and the formulation of high-value bioproducts in downstream processing. 

For her current research, Ruijie combines 3D imaging techniques and modeling methods to fundamentally understand the fouling mechanism within porous media during sterile filtration. For the doctoral work, she designed a novel single-pass tangential flow filtration (SPTFF) module for continuous concentrating proteins and buffer exchange flexibly. A concentration factor of 4.6 was achieved with a flow path of only 5 cm, while buffer exchange efficiency can be high as 99.9% when extended the length of the flow path to 25 cm and introducing an alternating flow direction of diafiltration buffer as internal back flush to reduce reversible concentration polarization. Such significant improvement has been successfully simulated using Multiphysics COMSOL, which elucidated the underlying mass transport of molecules within the module and validated that such a continuous diafiltration system has a diafiltration performance close to a 3-stage SPTFF system applying the same diavolumes.