Microphotonic Imaging Scanners and Microsystems for Early Cancer Detection

Sponsored by: Wallace H. Coulter Early Career Award in Biomedical Engineering, Tate Foundation, NSF SBIR award (subcontracted from: NanoLite Systems, Inc.), and National Instruments Medical Device Grant Program.


Handheld Confocal Microscope for Early Cancer Detection

The goal of this research is to develop miniaturized in vivo single fiber optic confocal endoscopes using silicon Micro-Electro-Mechanical systems (MEMS) technologies for the diagnosis of epithelial cancer in the oral cavity. MEMS scanners can be fabricated on a chip-scale and offer an excellent solution for scaling down the system for the endoscope-compatibility.  Two generations of instruments are assembled and tested. The first clinical handheld confocal microscope with 500 micron-diameter micro-mirrors was tested using epithelial tissue cell cultures with embedded gold nanoparticle reflective contrast agents. We further developed larger (1mm diameter) micromirrors, and a new objective system with higher magnification for improved signal-to-noise ratio. We then integrated the new mirrors with the objective system into a 50mm rigid length, 18mm diameter handheld probe with single-cell-layer optical sectioning (5µm axial resolution). We developed a second-generation clinical instrument to be placed for initial clinical testing.


In Vivo High-Speed 3D Volumetric Optical Coherence Tomography

Optical coherence tomography (OCT) has emerged as a high-resolution diagnostic imaging tool in cases where biopsy is difficult, for image-guided microsurgery, and for three-dimensional pathology reconstruction. Three-dimensional OCT enhances a physician’s visualization of morphology by providing tomographic, microscopic, and en face views simultaneously. Micro-electro-mechanical system (MEMS) technologies offer the unique capability to package micro-optical elements with actuators for imaging in in vivo environments. We have developed a swept source optical coherence tomography (SS-OCT) system incorporating silver-coated two-axis scanning micromirrors for high-speed 3D volumetric imaging of biological specimens. We have acquired real-time in vivo 3D images of human epidermis (Figures C, D) over a 2×1×4 mm3 volume with 12.5µm, 8.6µm lateral resolution at over 9.3 million volume pixels per second. In 2D imaging mode, we can acquired images at faster-than-video (40Hz) frame rates