Sandwiched Droplet Resonator for Low Concentration Protein Detection

This paper reports a sandwiched droplet resonator for low concentration protein detection using microfluidic chip (MFC). The droplet resonator integrated onto a single microfluidic chip consists of a sandwiched droplet and two optical fiber tapers that are directly placed into the droplet. The concentration measurement of protein is based on the shift of the resonant modes in the droplet resonator. The advantages of the resonator are the high quality factor (10⁴ to 10⁸), easy integration and no contamination, which promise the high accuracy (10^-5 to 10^-9 g/mL) measurement of protein concentration and label-free biosensing on the microfluidic chip.