Microstructural effects on permeability of Nitrocellulose membranes for biomedical applications

Nitrocellulose membrane (NC), as a paper-like matrix with microscale porous structures, has found widespread applications in biomedical fields due to its excellent biological features and physiochemical properties. In these biomedical applications, diffusion, convection, and binding reaction of biomolecules (e.g., acids and proteins) in NC through wicking flow is the fundamental physical process. However, the optimization of NC based biomedical devices has been limited by the lack of the understanding on the wicking flow behavior of NC membranes from the microstructural point of view. To address this, we experimentally and theoretically investigated the microstructural effects on the wicking flow behaviors (e.g., permeability, effective pore radius) of NC membrane and found that the wicking flow is highly dependent on the pore-morphology characterizing parameters (e.g., porosity and pore size). We further developed a theoretical model yielding a closed-form solution to predict the microstructure-permeability relation, which was validated by our experimental results. Our theoretical model would be a powerful tool for tailoring the wicking flow behavior of NC membranes through controlling the microstructural parameters, and thus for optimizing NC membrane-based biomedical devices from the view point of material design in the future.