Label-free DNA detection based on whispering gallery mode optofluidic microcavity biosensor

We proposed and experimentally demonstrated a sensitive, label-free, real-time and low-cost optofluidic microcavity biosensor for DNA detection. The change of whispering gallery mode (WGM) resonant wavelength is monitored by data acquisition card in real-time. The experimental results show that the biosensor can significantly distinguish the non-complementary single strand (ssDNA), single nucleotide mismatch ssDNA, and target ssDNA. In addition, a sensing mechanism based on WGM coupling depth was also experimentally demonstrated which would have potential for detection of biological and chemical analytes in the future.