| Microfabricated silicon nanoporous membranes (SNM) are a breakthrough technology with potential in biomedical applications that include, but are not limited to, artificial organs, drug delivery, cell encapsulation, and water purification. SNM have a number of highly advantageous characteristics when compared to polymer filters commonly used in such applications, such as increased chemical and mechanical stability. The characteristic of greatest interest, however, is the monodisperse pore size distribution achieved by the sacrificial removal of a highly controlled silicon oxide layer grown by thermal oxidation. The monodisperse pore size distribution allows for a greater level of characterization of pore and membrane behavior than would otherwise be possible. As such, investigations into the transport and electrical properties of SNM as a whole can be interpreted as an aggregate of individual pores. This work explores the electrical properties of the solution-pore interface via the streaming potential. This is followed by investigations of the size-based and charge-based filtration characteristics of the SNM using fluorescently labeled neutral and anionic Ficoll, a polysaccharide with low asymmetry. Finally, SNM are employed in the removal of endotoxin from an aqueous solution, a critical process in the production of medical grade water. |
