Mille-feuille paper is the first non-woven, wet-laid filter paper, composed of 100% native cellulose, which is capable of removing the “worst-case” model parvoviruses from water with a log₁₀reduction value (LRV) >5 (>99.999%).

Pressure-dependent breakthrough of nanobioparticles in filtration was observed and it was related to depend on both convective forces due to flow and diffusion as a result of Brownian motion. The aim of this work was to investigate the significance of Brownian motion on nanoparticle and virus capture in a nanocellulose-based virus removal filter paper through theoretical modeling and filtration experiments. Local flow velocities in the pores of the filter paper were modeled through two different approaches (i.e., with the Hagen–Poiseuille equation) and by evaluating the superficial linear flow velocity through the filter. Simulations by solving the Langevin equation for 5 nm gold particles and 28 nm ΦX174 bacteriophages showed that hydrodynamic constraint is favored for larger particles. Filtration of gold nanoparticles showed no difference in retention for the investigated fluxes, as predicted by the modeling of local flow velocities. Filtration of ΦX174 bacteriophages exhibited a higher retention at higher filtration pressure, which was predicted to some extent by the Hagen–Poiseuille equation but not by evaluation of the superficial linear velocity. In all, the hydrodynamic theory was shown able to explain some of the observations during filtration.

Scattering of ophthalmic devices is a complex phenomenon involving both surface and bulk light-material interactions. In this work, light scattering of nanocellulose reinforced PVA hydrogels contact lenses for ophthalmic applications was investigated. Optical microscopy, fluorescence microscopy and atomic force microscopy (AFM) techniques were used for ultrastructure characterization. Further, 3D angle resolved light scattering measurements in the visible spectral range were performed using a BTDF (bidirectional transmittance distribution function) sensor to quantify the scattered light. Surface and bulk scattering properties were discerned using white light interferometry. Total scatter levels ranging from 3% to 40% were observed depending on the hydrogel composition. The most critical factor affecting the light scattering properties in nanocellulose-reinforced PVA hydrogels was related to the state of hydration of the hydrogels, which is critical to maintain visual acuity of ophthalmic devices.