Beloglazova, Natalia

De Rycke, Esther

De Saeger, Sarah

Dubruel, Peter

Graniczkowska, Kinga

Hedström, Martin

English

Ghent University Academic Bibliography

IntroductionCapacitive sensor Immobilization on gold surfaceThis work is financial supported by the European Union’s Horizon 2020 Research and Innovation Program under Grant agreement No 653626 and FWO projectnumber 1S67817N. CapSenze Biosystems is highly acknowledged for their help and support in this work.AcknowledgementAffinity and selectivity E. De Rycke*, K. Graniczkowska, N. Beloglazova, M. Hedström, P. Dubruel, and S. De SaegerFaculty of Pharmaceutical Sciences, Laboratory of Food anaysis, Ghent University, Belgium* esther.derycke@ugent.beCapacitive based sensor for trace detection of amphetamine type stimulants in waterReferences:1. Lenain et al., Biosensor and Bioelectronics, 2015, Volume 69, pages 34-392. Graniczkowaka et al. Biosensors and Bioelectronics, 2017,Volume 92, pages 741-747MIPs were immobilized using tyramine as a linker. Reaction wasperformed through electro-polymerization in a galvanic cell for 15cycles from 0-1.5V. Dodecathiol was used to block active pinholes.An automated flow-injectionsystem was used to simulatecontinuously flowing systems.MIPs against N-FA were synthesized as follows: 50 µmol N-FA, 9 mmolethylene glycol dimethacrylate, 3 mmol hydroxyethyl methacrylate, 3mmol itaconic acid, and 0,3 mmol AIBN were dissolved in 2,5 mL DMF.2Fig. 3.1: Cyclic voltammogram of bareelectrode (blue) and after MIP-immobilization (purple).Fig. 3.2: Optical microscopy tovisually check the presence ofMIPs on the surface.Amphetamine-type stimulants (ATS) are the second most widely used drugs right after cannabis. Therefore, a robust and sensitive system, capable ofdetecting ATS, their metabolites, and their precursors in environmental water, is highly demanded. In this research, a selective detection system for N-formylamphetamine (N-FA) was developed. Over the last years, (label-free) capacitive sensors have established their own niche for analysis of low- and highmolecular weight compounds due to their high sensitivity, high selectivity, fast response time, and their possibility to miniaturize.When analyte binds, the electrochemical double layer (EDL) isdisplaced further away from the gold surface. Assuming a goodinsulation, the insulating and receptor layers will contribute theleast to the total capacitance. Hence, the partial capacitances of theanalyte and the electrochemical double layer is most pronounced.1The working electrodeconsists of several layersthat contribute to thesystem’s total capacitance.MIPThe polymerization was kept under UV light for20 minutes and subsequently heated at 80°Cfor 3h in an oil bath. The monolith (right, SEM)was griended and sieved wetly.Fig. 4.1: Net capacitance changes (nF),due to binding of the analyte, in functionof concentration (μM) Measurementswere performed in triplicate.This figure shows the affinity and cross-reactivity of immobilized MIPsagainst N-FA. As can be seen, these particles show a higher affinitytowards N-FA than to any other tested ATS. The limit of detection wasdetermined to be 5 µM. If higher concentrations of 500-1000 µM weretested, saturation of the MIPs occurs and the capacitive difference staysunchanged.ConclusionIn this research, selective MIPs against N-FA were succesfullysynthesized and immobilized on gold electrodes. Capacitive analysesshow that these MIPs have a limit of detection of 5 µM, and low cross-reactivity towards other ATS.Molecularly imprinted polymers (MIPs)Fig. 1.1: Schematic overview of capacitive sensor.Fig. 1.2: Different layers on working electrode.Fig. 2.1: Schematic overview of MIP-production process.Fig. 2.2: SEM of MIP monolith.

Capacitive based sensor for trace detection of amphetamine type stimulants in water

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Capacitive based sensor for trace detection of amphetamine type stimulants in water

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Ghent University Academic Bibliography