Imprinted Polydimethylsiloxane-Graphene Oxide Composite Receptor for the Biomimetic Thermal Sensing of Escherichia coli

This work presents an imprinted polymer-based thermal biomimetic sensor for the detection ofEscherichia coli. A novel and facilebacteria imprinting protocol for polydimethylsiloxane (PDMS)films wasinvestigated, and these receptor layers were functionalized with grapheneoxide (GO) in order to improve the overall sensitivity of the sensor.Upon the recognition and binding of the target to the densely imprintedpolymers, a concentration-dependent measurable change in temperaturewas observed. The limit of detection attained for the sensor employingPDMS-GO imprints was 80 +/- 10 CFU/mL, a full order lower than neatPDMS imprints (670 +/- 140 CFU/mL), illustrating the beneficial effectof the dopant on the thermo-dynamical properties of the interfacial layer.A parallel benchmarking of the thermal sensor with a commercialimpedance analyzer was performed in order to prove the possibility ofusing the developed PDMS-GO receptors with multiple readout platforms. Moreover,S. aureus,C. sakazakiiand an additionalE. colistrain were employed as analogue species for the assessment of the selectivity of the device. Finally, because of the potential that thisbiomimetic platform possesses as a low-cost, rapid, and on-site tool for monitoringE. colicontamination in food safety applications,spiked fruit juice was analyzed as a real sample. Reproducible and sensitive results fulfill the limit requirements of the applicable European microbiological regulation

Automated summary

This work introduces a thermal biomimetic sensor based on imprinted polymer for the detection of Escherichia coli, utilizing graphene oxide (GO) functionalized polydimethylsiloxane (PDMS) films to enhance sensitivity. The concentration-dependent temperature change serves as a detection mechanism, achieving a detection limit of 80 +/- 10 CFU/mL with PDMS-GO imprints, showcasing its superior performance.