Dual-tapered optical fiber structure-based LSPR sensor for cholesterol detection

Cholesterol plays a very important role in human physiological function, and the level of cholesterol in human body is a marker for diagnosing a variety of diseases. The article proposes a localized surface plasmon resonance (LSPR) sensor based on dual-tapered optical fiber (DTOF) that can detect cholesterol concentrations in the human body. To excite the LSPR effect and improve the sensing probe's sensitivity, gold nanoparticles (AuNPs) were immobilized on the surface of the DTOF. In this work, the specific reaction between cholesterol and cholesterol oxidase led to the change of refractive index (RI) near the sensing probe, and the corresponding spectrum is collected. Additionally, the performance of the sensor was evaluated, including linear range, reproducibility, reusability, stability, and selectivity. The experimental results demonstrate that the proposed DTOF-based LSPR sensor is capable of detecting the cholesterol level accurately and has a promising application in biomedicine.