Femtoliter-scale optical nanofiber sensors

We report a robust and sensitive optical nanofiber sensor with a femtoliter-scale detection volume. The sensor is fabricated by embedding a 800-nm-diameter nanofiber into a microfluidic chip with probing light propagated perpendicular to a 5-mu m-wide detection channel. To verify the effectiveness of the sensor, we present measurements of fluorescence intensity and refractive index (RI) with detection limits of 1 x 10(-7) M for fluorescein and 2.8 x 10(-4) RIU, respectively. The femtoliter-scale optical nanofiber sensor shown here may provide a compact and versatile sensing platform for sensitive and fast detection of ultra-low-volume samples, as well as studying the dynamics of single molecule. (C)2015 Optical Society of America