A Method for Modifying LSPR Biosensors With CeF₃ and Gold Nanobipyramids to Optimize the Sensitivity and Detection Limit of Interleukin

Surface plasmon resonance (SPR) technology is an advanced analytical method in the field of biological analytes detection. In order to break the limit of sensitivity and limit of detection (LOD) of optical fiber SPR sensor and enhance small change detection, a novel high-sensitivity optical fiber localized SPR (LSPR) sensor modified by cerium fluoride (CeF3) and gold nanobipyramids (Au NBPs) is proposed in this work. The refractive index sensitivity of the sensor is as high as 9414.90 nm/RIU, which is 4.99 times that of the traditional SPR sensor. The CeF3/Au NBPs sensor was applied to the detection of interleukin-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\beta $ </tex-math></inline-formula> (IL-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\beta $ </tex-math></inline-formula>) and IL-10. For IL-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\beta $ </tex-math></inline-formula>, the sensor’s sensitivity and LOD are 11.16 nm/(<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>g/mL) and 0.90 ng/mL. Compared with the traditional sensor, the sensitivity is increased by 3.73 times, and the LOD is reduced to 28.48%. For IL-10, the sensitivity and LOD of the sensor are 10.90 nm/(<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>g/mL) and 0.92 ng/mL, respectively. Compared with traditional sensors, the sensitivity is increased by 4.29 times, and the LOD is reduced to 23.35%. The sensor modified by CeF3 and Au NBPs shows excellent performance and broad development prospects in the field of low concentration biological analytes detection.