Electrochemical aptasensing utilizing titania-based surfaces for tetracycline detection

Electrochemical aptasensors been successfully applied in a number of fields, including food safety, enivormental monitoring and the health sector, providing a robust approach to the detection of a number of analytes. In particular, aptasensors have the advantage of flexible design, low immunogenicity and relative chemical/thermal stabilty. Moreover, aptamers, i.e in-vitro synthesized oligosequences, can offer a valid alternative to antibodies. In this work, we focus on electrochemical aptasensors based on semiconducting materials utilizing a mesoporous Mn:TiO₂ working electrode (WE) for the detection of tetracycline (TET). For this purpose, Mn:TiO₂ electrodes were prepared via the screen printing route, providing a low-cost approach. In particular, 5 μΜ οf the DNA aptamer with the following sequence: 5’-CCC CCG GCA GGC CAC GGC TTG GGTTGG TCC CAC TGC GCG-3’ [1,2] was used for the detection of different amounts of TET ranging from concentrations of 0.3 to 25.0 ng/ml in spiked aqueous samples. Detection was performed via differential pulse voltammetry (DPV) using a Pt wire cathode. In particular the buffer used in the experiment was Tris–HCl (20 mM, pH 7.6), 100 mM NaCl, MgCl2(2 mM), KCl (5 mM) and CaCl2(1 mM). The limit of detection was lower than the maximum residue limit required by the European Commmision for 100ng of tetracycline/mg, showing a low-cost alternative for TET detection.