Combined Thermal and Electrochemical Sensor Platform Employing a Novel Surface-Imprinted Polymer As Receptor for the Real Time Detection of Escherichia coli
Authors: Arreguin Campos Rocio Arreguin , Eersels Kasper , Diliën Hanne , van Grinsven Bart , Cleij Thomas J. 
Published: July 2021

Surface imprinted polymers (SIPs) are materials able to act as biomimetic receptors for different biological targets.[1] Their recognition ability is attributed to the presence of three-dimensional cavities on their surfaces that complement the target in shape.[2] Furthermore, the polymer binds to the analyte throughout interactions of covalent or non-covalent nature.[3], [4] Such interactions can be converted into measurable analytical signals by a transducer.[5]–[7] The combination of SIPs as recognition elements with different transducing elements make these sensing platforms a versatile alternative detecting tool in comparison to conventional diagnostic techniques.
In this work, a novel polyurethane-urea SIP for the real time detection of pathogen Escherichia coli is presented. The ability of the synthetic receptor to bind the analyte was assessed optically as well as quantitatively. The integration of the SIP into a flow cell allowed the detection of the analyte in one simultaneous read-out platform that combines electrochemical impedance and thermal measurements derived from the interactions at the solid-to-liquid interface. The results show that upon the exposure of the target in buffer within the flow cell, it re-binds to the polymer, resulting in an increase of the thermal resistance and a decrease of impedance, allowing the generation of a dose response curve for each transducer.
This study shows that the prepared polyurethane-urea SIPs are suitable to be implemented into a combined thermal and impedometric platform. Moreover, the results highlight the possibility of detecting quantitatively in real time the pathogenic analyte with the proposed sensor. This device could possess relevance in fields in which bacterial testing is required, such as food safety and medical diagnosis.
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