Molecularly-imprinted chloramphenicol sensor with laser-induced graphene electrodes

Supplementary data associated with this article can be found in the online version at doi:10.1016/j.bios.2018.10.015.Graphene has emerged as a novel material with enhanced electrical and structural properties that can be used for a multitude of applications from super-capacitors to biosensors. In this context, an ultra-sensitive biosensor was developed using a low-cost, simple and mask-free method based on laser-induced graphene technique for electrodes patterning. The graphene was produced on a polyimide substrate, showing a porous multi-layer structure with a resistivity of 102.4?±?7.3??/square. The biosensor was designed as? a 3-electrode system. Auxiliary and working electrodes were made of graphene by laser patterning and the reference electrode was handmade by casting a silver ink. A molecularly-imprinted polymer (MIP) was produced at the working electrode by direct electropolymerization of eriochrome black T (EBT). As proof-of-concept, the MIP film was tailored for chloramphenicol (CAP), a common contaminant in aquaculture. The resulting device was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy readings against a redox standard probe?. The limit of detection (LOD) was 0.62?nM and the linear response ranged from 1?nM to 10?mM. These analytical features were better than those produced by assembling the same biorecognition element on commercial graphene- and carbon-based screen-printed electrodes. Overall, the simplicity and quickness of the laser-induced graphene technique, along with the better analytical features obtained with the graphene-based electrodes, shows the potential to become a commercial approach for on-site sensing.The authors acknowledge funding from project PTDC/AAG-TEC/5400/2014, POCI-01-0145-FEDER-016637 and POCI-01-0145-FEDER007688, UID/CTM/50025/2013 funded by European funds, through FEDER (European Funding or Regional Development) via COMPETE2020 – POCI (operational program for internationalization and competitively) and by national funding through the Fundação para a Ciência e Tecnologia, I.P., Portugal (FCT-MCTES). ARC, ACM and AFC also acknowledge funding to National Foundation for Science and Technology, I.P., Portugal (FCT-MCTES) through the Ph.D. Grant SFRH/BD/130107/2017, SFRH/BD/115173/2016 and DAEPHYS-FCT PD/BD/114063/2015, respectively. AFC also acknowledges the funding from “Programa de Estímulo à Investigação 2016” from Fundação Calouste Gulbenkian.