Portable Automatic Micro-Ring Resonator System Using a Subwavelength Grating Metamaterial Waveguide for High-Sensitivity Real-Time Optical-Biosensing Applications
As the needs for bio-related detections continue to intensify in the healthcare industry due to the COVID-19 pandemic, our work on Si-microring slow-light systems comes as a timely aide with its small size, fast screening, and early diagnosis capabilities. The presented portable system integrates Si photonics with automated mechanical configurations in a platform that provides faster real-time readouts, higher sensitivities, all working within the optical telecommunication bands and ready for portable remote area point-of-care applications. The system weighs ~10 kg and is robust against movements. The graphic user interface written in MATLAB for system manipulation is easy to use. The relative resonance peak shifts in real time due to the surface refractive index perturbations in streptavidin detection for regular SWG microring resonators, proven for its excellent system performance in time response. A low concentration of streptavidin 10 μg/mL (~1.67 nM) was detectable by regular SWG microring resonators with a 0.15 nm resolution. Based on the successful streptavidin sensing, this portable system can be applied to the detection of a variety of tumor markers in developing simple “lab-on-a-chip” modules that are low cost and easy to use for rapid, high throughput cancer antigen sensing. With different specific receptors immobilized on the chip surface, it is also good for open applications in heavy metal detection, virus examination, and cancer diagnosis. We anticipate this would lead eventually to practical rapid diagnostic applications not only for early cancer detections but also for post-surgery or post-treatment follow-ups by providing convenience, consistency as well as efficiency.