Photonic Crystal Enhanced Microscopy for Characterization of Cell Attachment

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1132301CunninghamIntellectual MeritWe propose the development of a photonic crystal enhanced microscope (PCEM) as apowerful multimode imaging approach for quantification and visualization of the interactionsbetween cells and surfaces. The PCEM is designed to utilize the properties of a photoniccrystal (PC) biosensor surface that is designed to produce narrow bandwidth optical resonancesfor two distinct purposes. First, the resonant coupling condition of the PC is modified by cellattachment, and the PCEM is capable of producing images of the spatial distribution of cellattachment with sufficient resolution to quantify variations in the strength of attachment withinindividual cells. Second, the PC surface enables efficient coupling to laser illumination, resultingin the ability to enhance the output of fluorescent molecules in close proximity to the PC by twoorders of magnitude, using a technique called "PC Enhanced Fluorescence." The PCEM will bean enabling tool for a broad range of life science research and pharmaceutical screeningapplications that require characterization of the interaction between extracellular matrixmaterials and cell membrane-expressed proteins in response to cell growth, pro-apoptoticstimuli, forced differentiation protocols, chemotaxis, ion channel activation, transmembraneprotein activation, and proliferation. PCEM offers the ability to perform assays with a limitednumber of available cells for applications involving primary cells or stem cells. The proposedsystem builds upon the successful implementation and demonstration of the first PCEM system,which was designed and built for applications involving DNA microarrays and proteinmicroarrays. The proposed instrument incorporates objective-coupled illumination from aboveand below the PC for simultaneous label-free imaging, bright field imaging, and enhancedfluorescence imaging with optics designed to optimize the sensitivity and resolution of eachmodality when the PC surface is immersed in cell media. The system also incorporates a CO2environmental chamber to facilitate continuous monitoring of cells for extended periods of time.Broader ImpactsBiologists are developing a more sophisticated understanding of how cell membraneinteractions with surfaces, chemical stimuli, and other cells are modulated, and the role ofintegrins, ion channels, G-coupled transmembrane proteins, and filapodia in fundamentalprocesses such as migration, wound healing, differentiation, and apoptosis. Yet, there are fewtools currently available that allow visualization and quantification of these processes. While theinitial set of demonstrated applications for PCEM will include cancer cell cytotoxicity, T-cellinduced apoptosis, stem cell differentiation, and cardiac cell stimulation, the system'scapabilities extend to any cell type and any process that can be carried out upon a surface. Theenvironment at Illinois, in which the PI is an investigator within the NSF-sponsored Center forCellular Mechanics (CCMB) IGERT, and the NIH-sponsored Cancer Nanotechnology traininggrant, and the location of the system within the Micro and Nanotechnology Laboratory'sBioNanotechnology Laboratory assures that the system will be included in multidisciplinarytraining programs. Users of the system will be comprised of faculty, graduate students, andundergraduate students from Engineering, Pharmacology, Animal Sciences, Microbiology, andImmunology. The project will develop general-purpose methods for studying cell-surfaceinteractions that can be used broadly in pharmaceutical screening and life science research -extending the applicability of photonic crystal biosensors. The PI has a successful track recordof biosensor instrumentation invention, development, and commercialization.The proposal also describes an education plan that is closely linked with the program'stechnical goals with impact upon graduate student research, undergraduate research,undergraduate classroom/laboratory learning, and teaching biosensing/photonics concepts to aUniversity-based all-girls middle school. The PI has a strong track record for involvingundergraduate students in his research, and for making the technology developed under NSFfunding available in his ECE416 "Biosensors" course, both in the form of lecture topics andhands-on laboratory experience.