Proceedings of the Estonian Academy of Sciences, 4017, 66, 2, Proceedings of the Estonian Academy of Sciences, 2018, 67, 2, 138–146 https://doi.org/10.3176/proc.2018.2.04 Available online at www.eap.ee/proceedings Enhancing binding properties of imprinted polymers for the detection of small molecules Akinrinade George Ayankojo*, Jekaterina Reut, Andres Öpik, Aleksei Tretjakov, and Vitali Syritski Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia Received 19 October 2017, revised 15 January 2018, accepted 18 January 2018, available online 27 March 2018 © 2018 Authors. This is an Open Access article distributed under the terms and conditions of the Creative Commons Attribution- NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/). Abstract. This study demonstrates the promising steps towards improving the detection of small analytes in an aqueous solution by the quartz crystal microbalance (QCM) modified with a molecularly imprinted polymer (MIP) based sensitive layer. A homogeneous thin polymer film of poly(m-phenylenediamine) (PmPD) was electrochemically deposited on the surface of a QCM sensor in the presence of sulphamethizole (SMZ) acting as a template molecule. The binding capacity of the resulting SMZ–MIP films was enhanced by modifying the sensing surface with a diethylaminoethyl-dextran (DEAE-Dex) layer, forming a SMZ–MIP(Dex) film. The dextran layer allows further preconcentration of template molecules on the sensor electrode before polymer electrodeposition. The relative adsorption of the SMZ–MIP(Dex) films, as designated by the imprinting factors, was found to be in all cases significantly higher than that of the other films. At least about three times enhanced relative binding capacity of the modified imprinted polymer on the QCM sensor was established. A probe of the analysed sensor signals revealed that the modification steps significantly reduced the contribution from nonspecific interaction of the polymer matrix, thus suggesting beneficial effects of the dextran modification and template preconcentration. The presented approach promises a positive route towards an improved specific detection of small molecules by molecular imprinting on QCM sensor transducers. Key words: molecularly imprinted polymer, small molecule detection, sulphamethizole, quartz crystal microbalance, DEAE- dextran. 1. INTRODUCTION * The detection of small molecular weight analytes (drugs, toxins, chemicals, pollutants, etc.) is vital for environmental and biological interests (food safety, public security, environmental monitoring as well as pharmaceutical and biomedical analyses). Numerous analytical techniques (enzyme-linked immunosorbent assay, liquid chromatography, gas chromatography, mass spectrometry, and their coupling techniques) exist for the detection of various small analytes [1–4]. However, most of these techniques lack high specificity and * Corresponding author, akinrinade.ayankojo@ttu.ee their continued utilization is limited by the expensive detection instruments and complex procedures involved. Molecular imprinting is a technique that creates synthetic recognition materials, the so-called molecularly imprinted polymer (MIP), for detecting any molecule of interest, thus mimicking biological receptors. It polymerizes functional monomers in the presence of the target molecule that acts as a template. During polymerization, the template induces binding sites in the reticulated polymer that are capable of selectively recognizing the target molecules or similar structures following the removal of the templates from the polymer. The challenges of the traditional methods of detection are thus greatly overcome since MIP has been shown to