Optofluidic integrated one-dimensional photonic crystal biosensor for tumor marker detection

We propose a silicon based optofluidic one-dimensional photonic crystal biosensor structure for tumor marker detection, which is composed of a nanobeam resonator transducer with excellent detection limit performance, a filter with low sidelobe jitter and a microfluidics roof. Using the three-dimensional finite difference time domain method, a one-dimensional photonic crystal slot nanobeam resonator transducer optimization model consisting of a circular hole array linearly decreasing from the center to both ends was obtained. Under the influence of absorption loss of biological solution, the transducer works in the communication E-band, with the Q value still up to 10538, refractive index sensitivity of 338 nm/RIU, and refractive index detection limit of 10-5 RIU, corresponding to the detection of fg/mL carcinoembryonic antigen, which can be directly used for the detection of tumor marker under the capture of antibody probes in microfluidics chip. By optimizing the apertures on both sides of one-dimensional photonic crystals with a taper shape, a cutoff filter with low sidelobe jitter can effectively filter out the high-order resonant peaks of the transducer, forming a large free wavelength detection range. The microfluidics channel is used to inject different refractive index liquids, and the cut-off wavelength can match the detection requirements of different concentrations of tumor markers. The sensor structure is expected to build a multi-channel parallel lab-on-chip through splitters and detect multiple tumor markers simultaneously.