Electrokinetic transport of molecules through nanochanneled membranes

Our research group was the first one to microfabricate and demonstrate nano-channels in silicon membranes (1, 2). We employed nano-channeled chips to provide immuno-isolation for cell transplantation towards the treatment of diabetes (3), for biomolecular separation (4), and for the controlled passive and active release of drug molecules from implanted capsules (5). We showed that the constraints placed upon molecular agitation in nano-channels affected their concentration-driven transport kinetics (6, 7). A zero-order passive release of biological molecules was achieved, by the rational tailoring of nano-channels dimensions. This achievement allowed releasing of a constant amount of drugs over a long period of time. However, the development and optimization of many drug therapies require long-term drug delivery with controlled but variable dosage using miniaturized systems (8). Moreover, application such as drug release from implanted devices requires tight operational control, of regulatory agency caliber. We have engaged in the development and characterization of elecroosmotic nano-channels membranes, and present our results in this communication. These include the influence of the drug release rate on nanochannel size, membrane configuration, and applied voltage.