Karen Daniel, Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, Grace Kim, Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, Christophoros Vassiliou, Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, Michael Cima, Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, and Robert Langer, Chemical Engineering and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142.
There are many potential clinical applications for local drug delivery and sensing systems, such as vaccinations, cancer therapy, pain management, and hormone therapy. Localized drug delivery systems reduce both the amount of drug required for a therapeutic effect and the severity of side effects associated with treatment. Localized sensing systems will allow early detection of diseases and provide a tool for developing personalized treatment programs. We present a polymeric reservoir-based device that can be implanted non-invasively for localized drug delivery or sensing applications. One specific application that will be presented is detection of cancer-related analytes. This application combines the sensing capabilities of nanoscale magnetic relaxation switches (MRSW) and the microfabricated polymer device to create powerful implantable multiplexed sensors. MRSW are magnetic nanoparticles (iron oxide core, crosslinked dextran shell) that are functionalized to detect a variety of analytes down to attomolar sensitivity. In the presence of analyte, the MRSW aggregate, causing a change in relaxation state that can be detected via NMR or MRI (Perez et al., 2002). We will present in vitro diffusion experiments used to optimize the device design and fabrication and in vitro sensing experiments used to characterize the device performance. Perez et al., Magnetic relaxation switches capable of sensing molecular interactions. Nature Biotech, 2002, 20, 816.