1. Development of high-density photonic sensor chips Robert Magnusson Electrical & Computer Engineering University of Connecticut and Resonant Sensors Incorporated NSF workshop on Biosensing and Bioactuation 27-28 November 2007 University of Maryland

2. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.2 Guided-mode resonance sensor Concept Selective sensing enabled with standard biochemical recognition reactions -Antigen-antibody, enzyme-substrate, ligand-receptor, DNA - No fluorescent/absorption tags required

3. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.3 Motivation for R&D: Important applications Pharmaceutical drug discovery –Increase the rate of identifying promising new drugs –Decrease the cost and time to market –Ability to screen arrays of analytes in high volume Homeland/environmental security –Accurate and low-cost detection of toxic materials (including bacteria) in air and/or water environments Key requirements of these applications: Low cost of equipment and operation Minimize false readings, maximize detection sensitivity Real time Direct detection (tag-free sensing) High throughput assays Flexibility in system design and footprint

4. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.4 Fast - instant results Outstanding accuracy – cross referenced data High sensitivity – detection of small molecules to large bacteria High resolution – sharp detection peaks, high signal to noise Mass producible – high density formats Initial market applications in drug discovery and proteomics: Antigen-antibody assays, peptides and cell-based assays, DNA arrays Captured biomolecules  Change in reflected color of light (1) Baseline (2) After analyte binds  Wavelength ( ) Reflectance Sensor element Guided-mode resonance sensor technology Positive attributes

5. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.5 Chief GMR sensor features FeatureGMR sensor attribute PolarizationArbitrary; pure TE or TM polarization state is often convenient. Incidence angleAny, including zero. Mode structure Complex; higher modes can provide new peaks for added sensitivity and accuracy. Typical linewidth ~1-10 nm, controlled by refractive index contrast of grating and fill factor. Sensitivity High; computed estimates ~10 -6 refractive index and ~10 -2 nm in thickness. Can be aided with polarization diversity and additional resonance peaks. AccuracyHigh; narrow resonance peaks, cross-referenced in polarization. EfficiencyHigh; near 100% experimentally demonstrated.

6. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.6 Assay processing comparison Features Current label-based approaches Guided-mode resonance sensor system Time to measure biochemical reaction4-24 hours (typical).<15-30 minutes (typical). Chemical processing to detect biochemical reaction 2-3 incubation steps and 10-15 washing steps before readout. Real-time, direct monitoring of biochemical reaction. Sensitivity pM range (commercial benchtop plate readers).pM to fM range Binding kineticsnot capableyes Distinguish binding events from background refractive index/density changesnot capable yes; able to quantify background index and distinguish from binding event.

7. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.7 Polarization diversity in GMR biosensing Sensor element Streptavidin Biotin Silane GMR sensor element Analyte Antibody Detector array (TE and TM polarizations) Laser Multiple resonance peaks allow the user to potentially distinguish background density changes from a targeted reaction

8. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.8 Resonant optical sensor technology Summary New enabling sensor technology –Performance leap wrt existing technology –Integratable, planar, thin, mass-producible; biochip format possible –No labels needed –Strongest combination of performance/engineering issues in a photonic sensor Applications –Drug discovery/development - HTS –Water/food/air monitoring –Sensing biomolecules and chemicals –Medical diagnosis/genomics –Homeland security –Environmental integrity assurance

9. Magnusson, Electrical&Computer Engr, University of Connecticut, and Resonant Sensors Inc.9 Chief challenges Generalizable to other sensor technologies Integrating the sensor chips with signal extraction- and data processing electronics consuming low power. Incorporating exact electromagnetic inversion codes and wireless signal transmission capability into the electronics. Deployment in sensor network architectures. Developing economic fabrication technology for ~10,000 sensor pixels/cm2 (nanoimprint lithography). Rapidly, accurately sensitizing high-density pixel arrays with proper antibodies, chemical links, etc. (nanorobotics). Integrating arrays into microfluidic systems for sensor regeneration and redeployment under remote control or automatic response to environmental changes (smart sensor). Designing highly sensitive elements for air and water operation, robust under a variety of environmental conditions. Developing reliable, light-weight, compact, self-powered systems that are portable and patient/nurse/soldier etc. operable.