Molecularly imprinted biomimetic QCM sensor involving a poly(amidoamine) dendrimer as a functional monomer for the highly selective and sensitive determination of methimazole

Abstract

This study describes the development of a poly(amidoamine) (PAMAM) dendrimer-based molecularly imprinted biomimetic QCM sensor for methimazole (MMI) determination. This report is the first involving a PAMAM dendrimer as a functional monomer used during the imprinting process to enhance the amount of recognition sites in the polymer matrix to improve the recognition ability. The PAMAM dendrimer (3.0 generation) was first grafted using methacrylic acid (MAA), and the obtained PAMAM–MAA monomer was characterized using FT-IR and NMR spectra. Furthermore, an MMI imprinted material using PAMAM–MAA as a functional monomer was synthesized and modified on the surface of a quartz crystal Au electrode to develop a novel molecularly imprinted biomimetic QCM sensor. Through evaluation over a series of experiments, the QCM sensor exhibited significant selective adsorption, as well as recognition for the template, and provided a highly selective and sensitive strategy for determining the MMI in urine samples. At three spiked concentrations (2.0mgL−1, 4.0mgL−1, 8.0mgL−1) in different urine samples, the recoveries for the measurements ranged from 84.4% to 91.7% with SD of 1.4–6.3% (n=3), indicating that the prepared sensor has high accuracy and precision for determining MMI in complex biological samples.