An Experimental Study On The Microfluidics-Based Adsorption-Dialysis Membrane

The kidney failure is one of the very common acute diseases, and its morbidity continues to increase all over the world. The blood purification system, such as artificial kidney, is the main method to keep patients alive. The next for blood purification system is miniaturization. However, the implantation of blood purification system in vivo hasn’t been achieved and even the portable machines haven’t been reported so far. Recently, the rapid development of microfluidics makes it possible to integrate dialysis in the micro-device, which enables the miniaturization of blood purification system.The on-chip fabrication of a carbon nanoparticle-chitosan composite membrane (i.e. a sorbent membrane or a composite membrane) using laminar flow-based interfacial reaction is presented in this paper. In addition, the effects of carbon nanoparticles and reactant flow rates on membrane formation are investigated. Finally, the permeability and adsorption capacities of the membrane are discussed. During fabrication, an acidic chitosan solution and a basic buffer solution that contained carbon nanoparticles were introduced into a microchannel. At the flow interface, a freestanding composite membrane with embedded carbon nanoparticles was formed due to the deprotonation of the chitosan molecules. The composite membrane growth gradually stopped with time from upstream to downstream and the thickness of the membrane increased rapidly and then slowly along the reactant flow direction. The formation of the composite membrane was divided into two stages. The average growth rate in the first stage was significantly larger than the average growth rate in the second stage. Carbon nanoparticles in the basic solution acted as nucleating agents and made the membrane formation much easier. As the flow rate of the chitosan solution increased, the averaged membrane thickness and the membrane hydraulic permeability initially increased and then decreased. Because of the addition of carbon nanoparticles, the formed membrane had adsorption abilities. The micro-device containing composite membrane is of great significance to the development of miniaturized blood purification system.