Human IgM detection using an optical fibre long period grating sensor

An optical fibre long period grating sensor coated with three layers of poly (allylamine hydrochloride) and silica core gold shell nanoparticles was developed for the detection of human IgM. Three different concentrations of IgM suspension (19nM, 83nM and 0.3 μM) were detected. The sensor response time is less than 8 minutes and the binding of IgM can be observed dynamically at a concentration of 0.3 μM. The binding constant of IgM on the LPG sensor is 23.9 (pM)
^-1
based on the fitting of the Langmuir adsorption isotherm. The sensitivity of the LPG sensor is calculated as 11 nm/ (ng/mm
²
) with a limit of detection of 0.0218 ng/mm
²
.