Molecular Imprinting Polymer Nanoparticles Coupled with an Optical Sensor for Sensitive and Label-Free Detection of p-Cresol

Selective detection of toxic pollutants present in waterhas beena severe challenge to the scientific community for a long time. Thenoble integration of optical fiber-based interferometry with a bio-recognizingelement molecular imprinting polymer (MIP) exhibits a promising techniquefor selective and susceptible biochemical detection. Here, we reporta compact, stable, reproducible, and label-free optical sensor usinga combined approach of photonic crystal fiber (PCF)-based modal interferometryand MIP nanoparticles (MIP-NPs) for selective detection of water pollutant p-cresol with an extremely low limit of detection (LOD).The MIP-NPs having a greater surface-to-volume aspect ratio allowsmore target analytes to bind. The sensor immobilized with MIP-NPsshows unprecedented sensitivity of 1.865 x 10(8) nm/Mwith specific and repeatable detection performance for a broad dynamicdetection range of 10(-8)-10(-3) M. The sensor offers a remarkable detection ability of as low as1.55 nM concentrations of p-cresol in the aqueousmedium, for water quality monitoring. Fast response, high resolution,compact size, label-free broad detection range, and selective reusableperformance of the proposed sensor exhibit potential for board practicalutilizations, including medical sectors, online and remote biosensing,and water resource monitoring.