Nanostructured porous silicon membrane for hemodialysis

Hemodialysis treatment of patients, with either acute or chronic renal failure, has had a dramatic impact on the mortality rates of these patients. The main component of the hemodialysis machine is the dialyzer. The dialyzer contains semi-permeable membranes which filter the blood. Despite the progress made, this membrane-based therapy is still incomplete renal replacement, as the mortality and morbidity rates remain unacceptably high. An important characteristic of the performance of the membrane is its pore size, porosity and thickness. Commercial dialyzer membranes are over a 1000 times thicker than the dimensions of the molecules which will be filtered, thus leading to low transport rates, and retention of solutes in the pores. Ultrathin nanostructured membranes are capable of addressing this issue, where the membranes have a thickness of around 1 micron. Microfabricated thin porous silicon (Si) membranes have great potential in molecular filtration applications due to the ability to tailor its properties, and control pore size and porosity by using XeF₂ dry etching technique. The mechanical strength of these thin membranes has been their limitation. Thus, further studies on improving the mechanical behavior of the thin membranes are needed.