Low cell concentration detection by Fabry-Pérot resonator with sensitivity enhancement by dielectrophoresis

Abstract A yeast cells detection system that combines cell focusing and refractive index measurement is designed to realize label-free, high-resolution cell concentration detection. In our design, Fabry-Perot (FP) cavity is utilized to conduct the volume RI detection, by which the lightwave can completely permeate the bulky sample solution with strong light-matter interaction, thus it is particularly valuable for ultra-low concentration biological analytes detection. To further improve the sensor sensitivity, dielectrophoresis (DEP) is applied to spatially accumulate the uniformly suspended yeast cells in the light spot region. The final concentration of aggregation was about 50 times the initial state. By using the designed DEP-FP sensing system, a sensitivity of 0.121nm/(amol/mL) (2 × 10−7nm/(cells/mL)) and a resolution of 3.65 × 105 cells/mL is obtained. Due to its top performance for cell concentration detection, this device may have potential applications in molecular cell biology, pharmacology, and biochemistry.