Our group will be developing modular microsystems that can be assembled in a variety of different configurations to carry out complex biomedical assays appropriate for monitoring both genetic and protein markers in clinical settings. Our focus in this R21/R33 application will be screening diagnostic markers associated with breast cancer. The focus of our project is to build upon our existing expertise in LIGA to fabricate BioMEMs devices possessing high-aspect ratio microstructures (HARMs) fabricated out of a variety of polymer materials. Specifically, we will be fabricating the following modular devices: (1) Microsampling unit with target preconcentration capabilities of rare cancer cells in circulating blood. Our microsampling unit will consist of capture beds prepared using surface imprinted polymers to semi-selectively capture pre-selected targets (cells expressing EpCAM). (2) Cellular lysis system. Captured cells will be electrodynamically lysed using microfabricated electrodes to induce cell rupture via electroporation. (3) Multiplexed hybridization association unit. To signal the presence of either a mutant gene or protein that is under- or over-expressed, we will build arrays of elements consisting of tethered nucleic acid probes or antibodies (Ab) to associate selectively with our targets. Since both genetic and protein markers can be effective in diagnosing a particular disease state, we will build hybrid systems (hybrid-biosensors) that will monitor simultaneously both genetic and protein markers to minimize false positives and negatives associated with the diagnosis. (4) Micro-optical bench with high sensitivity laser-induced fluorescence components. The transduction of the hybridization of target DNAs to our tethered probes or association with tethered Ab will be determined using near-IR fluorescence with excitation provided by a surface mounted vertical cavity surface emitting laser (VCSEL) and the sensing elements situated on a planar polymer waveguide. (5) Ultrasensitive probes for fluorescence transduction. Our fluorescence detectors will be configured to read luminescence generated in the near-IR by developing labeling probes that possess spectral properties in the near-IR (excitation/emission maxima > 700 nm).
