Authors: G.Y. Kim, K.D. Daniel, C.C. Vassiliou, N. Elman, L. Josephson and M.J. Cima
Affilation: MIT, United States
Pages: 218 - 220
Keywords: nanoparticle, biomarker, sensor, implantable, bHCG
This implantable biomarker sensor combines nanoscale magnetic relaxation switches (MRSW) and the versatility of microfabricated structures tp be read by MRI. MRSW are magnetic iron oxide nanoparticles that can be functionalized to detect a variety of analytes (Perez, Nature Biotech 2002). The presence of analyte causes the MRSW to aggregate, causing a change in T2. The MRSW are packaged into a device to expose the MRSW to the tumor milieu. MRSW were functionalized to detect the beta subunit of human chorionic gonadotrophin (betaHCG), which is elevated in testicular and ovarian cancers. The addition of betaHCG to the MRSW resulted in T2 shortening as seen in test-tubes and in prototype devices by NMR spectroscopy and MRI respectively. This biomarker sensor will be tested in cell lines producing betaHCG and in nude mice bearing ectopic tumors. To our knowledge, this is the first nanoparticle system to detect betaHCG biomarker via T2 shortening. This is also the first demonstration of T2 shortening response inside a semi-permeable device. This method can be adapted to detect other circulating biomarkers.