Cost-effective optical biosensing using integrated photonics (Conference Presentation)

Abstract

Cost-effective Point-of-Care (POC) diagnostics are of considerable interest to modern healthcare. Current POC devices are typically disposable, low-complexity, and qualitative, with quantitation only achievable at significant additional cost. Clinical diagnostic tools in centralized labs provide better quantitation, but are cumbersome, time-inefficient, expensive, and require trained operators. We hypothesized that Si3N4 and SU-8 photoresist ring resonators would allow for quantitative and inexpensive sensing of clinically relevant serum biomarkers. To test this hypothesis, we designed silicon nitride-based ring resonators that were then fabricated at the American Institute for Manufacturing Integrated Photonics (AIM Photonics). We also designed SU-8 polymer ring resonators, and fabricated those using in-house facilities. Single mode waveguides were designed for transverse electric and transverse magnetic polarizations at λ=1550 nm using COMSOL Multiphysics® and PhoeniX OptoDesigner. Devices were addressed by end-fire coupling and characterized by assessing spectral features including quality factor, finesse, and free spectral range. Bulk solution refractive index sensitivity was achieved using sucrose solutions. Specific interaction was shown by spiking C-Reactive Protein (CRP), an indicator of inflammatory response, into fetal bovine serum and identifying concentration dependent wavelength shift. This discussion will focus on device design, characterization, and the ability of silicon photonics to sense clinically relevant biomolecules in the label-free regime.