Molecularly Imprinted Photonic Crystal Sensor for Rapid Onsite Detection of Creatinine

Abstract

There is an ever-increasing demand for simple, selective, accurate, and reliable assays for the determination of clinically important metabolites as indicators of health status. Creatinine is the by-product of muscle energy metabolism and is produced at a constant rate related to the muscle mass of the individuals and is excreted by kidneys. To measure creatinine in the human urine sample, a creatinine imprinted photonic crystal hydrogel (CIPC hydrogel) sensor for naked-eye detection is developed. The sensor utilizes polystyrene-based two-dimensional (2D) photonic crystal colloidal arrays (2D PCCA) embedded in the polyacrylamide hydrogel containing methacrylic acid as the functional monomer which imprinted the creatinine template. The nanocavities in the hydrogel produced after removal of the template bind to and recognize creatinine in the urine samples. The binding is selective for creatinine, which is evidenced by shrinkage of the hydrogel and decrease in the particle spacing monitored through changes of the Debye diffraction ring diameter and a visible blue-green to blue color shift. The CIPC sensor demonstrates a limit of detection (LOD) of 3.32 ± 1.5 µM, linear detection range (1-500 µM), and recovery from 97.9 % to 99.0 % in the urine samples. The sensor is available for the rapid and quantitative onsite detection of creatinine in the human urine sample.

Keywords: creatinine, photonic crystal, hydrogel, Sensor