Nanoporous Membrane Fabrication by Nanoimprint Lithography for Nanoparticles Sieving

Isoporous membrane with strictly controlled pores size, shape and distribution could provide an efficient, precise and mild sieving of particles in nanotechnology and biomedical applications. However there is a lack...

Diffusion-Based Separation of Extracellular Vesicles by Nanoporous Membrane Chip

Extracellular vesicles (EVs) have emerged as novel biomarkers and therapeutic material. However, the small size (~200 nm) of EVs makes efficient separation challenging. Here, a physical/chemical stress-free separation of EVs based on diffusion through a nanoporous membrane chip is presented. A polycarbonate membrane with 200 nm pores, positioned between two chambers, functions as the size-selective filter. Using the chip, EVs from cell culture media and human serum were separated. The separated EVs were analyzed by nanoparticle tracking analysis (NTA), scanning electron microscopy, and immunoblotting. The experimental results proved the selective separation of EVs in cell culture media and human serum. Moreover, the diffusion-based separation showed a high yield of EVs in human serum compared to ultracentrifuge-based separation. The EV recovery rate analyzed from NTA data was 42% for cell culture media samples. We expect the developed method to be a potential tool for EV separation for diagnosis and therapy because it does not require complicated processes such as immune, chemical reaction, and external force and is scalable by increasing the nanoporous membrane size.

Enhanced Mechanism of Water Evaporation Through Nanoporous Membrane

Evaporation through nanoporous membrane has attracted tremendous research attention as a ubiquitous natural phenomenon, which can be used in numerous applications. In this work, we explored the ultrathin water film evaporation process on nanoporous membrane based on non-equilibrium molecular dynamics simulation. A heat localization design of multilayer graphene coated at the bottom of membrane was implemented to reduce the heat loss along the non-evaporation direction. The underlying mechanism of water evaporation through nanoporous membrane was investigated after analysis of the average number of hydrogen bonds per water molecule, the temperature variation and the mean squared displacement of water molecular during the evaporation process. The results showed that the change of pore size will affect the water molecules structure. We also discussed the effect of heat localization design on ultrathin water film evaporation process. The result suggested that water molecules are more active and evaporation efficiency is improved correspondingly. This work reveals the feasibility of the novel nanoporous membrane structure design for enhancing heat and mass transfer, which can be adopted in efficient thermal management and low-cost approaches for water desalination.