A Self-Contained Optical Heterodyned Second Harmonic Sensor

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, and partial co-funding from the Biosensors Program in CBET, Professor John Conboy and his research group at the University of Utah are developing a novel optical biosensor capable of detecting and quantitating a wide range of biological molecules. The proposed research seeks a reliable, highly sensitive, multiplexed, label-free biosensor for analytes such as biomarkers found in blood, serum, urine, or other fluids. The approach can enhance clinical diagnostics and field detection of biological agents. Integrated with the research is education of both graduate and undergraduate students in bioanalytical/biophysical methods and techniques. The team is also engaged in outreach to regional schools, aiming to attract students, including students from underrepresented groups, to STEM (science, technology, engineering and mathematics) careers. The need for analytical methods capable of biomarker detection and quantification is clear. Antibodies, with their exquisite chemical specificity and high affinity, are exceptionally well-suited for bio-specific detection and quantification. However, utilizing antibodies for the direct label-free detection of low molecular weight biomarkers in a noncompetitive immunoassay represents a major technical challenge due to the difficulty of sensing the capture event. The Conboy group is using the nonlinear optical Second Harmonic Generation (SHG) technique to develop a highly sensitive, label-free biomarker biosensor. A key aspect of this biosensor is a unique optical heterodyned detection system which significantly enhances the otherwise weak SHG response. This novel sensor approach is capable of detecting most targets with pi-electrons, which makes it sensitive to many biomarkers of interest, creating a highly versatile, label-free detection modality. The methodology under development in this project is expected to provide a unique analytical approach that does not compromise sensitivity, yet provides a cost-effective and flexible label-free noncompetitive biomarker immunoassay. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.