Optimization of angle-pixel resolution for angular plasmonic biosensors

An angular plasmonic sensor based on optimized angle-pixel resolution to detect antibody-antigen binding process is presented. Owing to discrete resonance curves by the CCD pixels, the pixel sensitivity and detection noise of the plasmonic sensors need to be balanced. The angle-pixel resolution is adjusted by changing the distance between the sensor chip and the CCD to obtain the optimal refractive index (RI) resolution for three plasmonic sensors, which are surface plasmon resonance (SPR), long range surface plasmon resonance (LRSPR) and plasmon waveguide resonance (PWR) sensors. Each plasmonic sensor can achieve its optimal RI resolution at the optimal distance, and the LRSPR sensor has the best RI resolution. Attributing to the reference channel and temperature control module in the sensor system, the RI resolution can achieve 4.37 × 10 −7 RIU at Normal mode and 1.13 × 10 -7 RIU at a slow response Extreme mode. The Protein A-IgG binding reaction experiment indicates that the plasmonic sensor has linear response to IgG concentration in a wide range and the limit of detection (LOD) is 5.45 pM at Extreme mode. The procedure and result of this work are helpful to the optimization of other angular plasmonic sensors.