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.
Current research is focused on the miniaturization and integration of detection devices for biological targets in order to adapt to outdoor and emergency field settings, as well as to enhance the flexibility and practicality of detection. This study proposes an ultra-high integrated silicon nitride fluorescence excitation chip for point-to-point excitation of biological fluorescence signals. By employing the finite-difference time-domain(FDTD) method and utilizing silicon nitride as the functional material, a visible light fluorescence excitation chip operating at the wavelength of 645nm was designed and fabricated. The chip is composed of an input grating coupler, multiple multimode interferometers, and output grating couplers. A grating array containing 2016 excitation points is constructed cascading multiple multimode interference splitters and connecting excitation gratings at the terminals. The single grating coupling efficiency of the chip is 30% with a total excitation light area of 4×4mm² and an emitted light angle of around 80 degrees. By adjusting the positions of different output grating couplers, the chip can adapt to excitation requirements at different locations, making it suitable for various applications such as fluorescence quantitative polymerase chain reaction(PCR) and digital PCR. With the help of microfluidic chambers and a photodetector, the chip successfully achieved the detection limit of 0.5 µmol/L Cyanine 5(Cy5) fluorescent reagent solution, which is sufficient for direct detection of PCR fluorescence signals.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.