Characterisation of a label‐free biosensor based on long period grating

Abstract

Optical fibre gratings, especially long period gratings, have been recently proposed as optical devices for biochemical sensing. A biochemical interaction along the grating portion induces a refractive index change and hence a change in the fiber transmission spectrum. This provides an alternative methodology with respect to other label-free optical approaches, such as surface plasmon resonance, interferometric configurations and optical resonators. The fibre biofunctionalization has been carried out by means of a novel chemistry using Eudragit L100 copolymer as opposed to the commonly used silanization procedure. Antigen-antibody interaction has been analysed by means of an IgG/anti-IgG bioassay. The biosensor was fully characterised, monitoring the kinetics during the antibody immobilization and the antigen interaction and achieving the calibration curve of the assay. A comparison of the biosensor performance was made by using two different long period gratings with distinct periods.

EDC-Mediated Oligonucleotide Immobilization on a Long Period Grating Optical Biosensor

“…The maximum RI sensitivity (794 nm/RIU) in low range RIs of 1.30-1.35 of our dLPG is more than 50 times higher than that of previously reported 370 µm period LPG sensor, who achieved an RI sensitivity of 15 nm/RIU around 1.33 RIU [31]. Hence, biosensors based on dLPGs should achieve comparable or better performances with respect to the standard LPG or mFBG based biosensors [12,31].…”

“…Hence, biosensors based on dLPGs should achieve comparable or better performances with respect to the standard LPG or mFBG based biosensors [12,31].…”

Label-free oligonucleotide biosensor based on dual-peak long period fiber grating

“…. Hence, biosensors based on dLPGs should achieve comparable or better performances with respect to the standard LPG or mFBG based biosensors 8,11 . Figure 2.…”

“…Since they are in close proximity to the dispersion-turning-point, the dual-peak cladding modes are extremely sensitive to the surrounding-medium refractive index (SRI) change. To date, various fiber optic biosensors have been developed for the detection of antibody-antigen interactions, biotin-streptavidin, DNA hybridization, enzyme-glucose binding and cellular behavior 5,7,11 .…”

Manufacturing and Spectral Features of Different Types of Long Period Fiber Gratings: Phase-Shifted, Turn-Around Point, Internally Tilted, and Pseudo-Random

“…[5][6][7][8][9][10][11] up to sensing applications (physical, chemical and biological sensors, etc.) [12][13][14][15][16]. However, given the easier and cheaper customization of LPFGs' manufacturing process, the topic of this paper will be entirely focused on them.…”