Long period grating based molecularly imprinted fiber optic sensor for the label-free detection of bisphenol A

Abstract

The molecularly imprinted fiber optic (MIFO) sensors are recognized for its reliability, sensitivity and selective analyte identification. In this study, we report a Long-Period Grating (LPG) based MIFO sensor developed for the label-free detection of Bisphenol A (BPA) in water samples. The sensor is fabricated by polymerizing hydrogel precursor containing BPA on the LPG, followed by etching BPA molecules. The rebinding of the BPA molecule to the molecularly imprinted long period grating Bisphenol A (MILPG-BPA) sensor causes the hydrogel to swell, leading to a peak shift in the LP07 resonant mode of the sensor. This shift is linear across BPA concentrations ranging from femto molar to nano molar range with a low limit of detection of 0.146 fM. The non-imprinted long period grating (NILPG) sensor showed no selective binding of the BPA molecule, underscoring the significance of the microenvironment established through molecular imprinting for effective sensing. The MILPG-BPA sensor exhibits high selectivity in detecting the BPA molecules among the potential interferents. Furthermore, it has a rapid response time and reusability, thus holding promise for a wide range of applications.