LSPR-Based Cholesterol Biosensor Using Hollow Core Fiber Structure

Abstract

In this paper, a cholesterol biosensor is developed using a single-mode fiber (SMF) and a hollow core fiber (HCF) to detect and measure the cholesterol concentration in the human body. The sensitivity of an SMF-HCF structure (sensor probe) has been enhanced by the localized surface plasmon resonance (LSPR) technique using the gold nanoparticles (AuNPs) of 11± 0.5 nm particle size. Furthermore, sensor probe was functionalized with cholesterol oxidase (ChOx) enzyme to increase the selectivity of biosensor. The synthesis of AuNPs is confirmed by a UV-visible spectrophotometer, transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy (EDS). Furthermore, the coating of AuNPs over an optical fiber is verified by scanning electron microscope (SEM). The linearity range and detection limit of the proposed sensor are 50 nM– $1~\mu \text{M}$ and 25.5 nM, respectively. The selectivity of biosensor has been determined with the 10-mM concentration of different solutions of cholesterol, glucose, urea, ascorbic acid, L-cysteine, and galactose that are generally present in serum.