Piezoelectric sensors for dioxins: a biomimetic approach

The aim of this work was to design a fast, cheap and easy to use analytical system for dioxins. Piezoelectric sensors coupled withthe pentapeptides as biomimetic traps (the receptors), selective for the dioxins, were used for the realisation of this analytical system. Amethodology to select specific receptors among all possible pentapeptides randomly generated was represented by the use of molecularmodelling software. Three peptides called later on A, B and C (A:[N]Asn-Phe-Gln-Gly-Ile[C]; B:[N]Asn-Phe-Gln-Gly-Gln[C]; C:[N]Asn-Phe-Gln-Gly-Phe[C]), were selected and evaluated for their potential usage as artificial receptors in solid–gas analysis by using a quartzcrystal microbalance (QCM) sensors array. The peptide sequences were functionalised by two terminal cysteine residues in order to achieve acovalent interaction with theQCMgold surface.Amanganese–porphyrin complex and two other pentapeptides, a pentaglutamine (pentapeptideD) and a pentalysine (pentapeptide E), were used as negative control sensors. The QCM sensors (A, B and C) gave a good linearity againstdifferent sample concentrations of the 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) and a mixture of dioxins. In particular, the selectivityagainst 2,3,7,8-TCDD was nicely correlated to the estimated binding energy of the receptors calculcated by computational modelling. Thecross-reactivity of the system was quantified using commercial polychlorinated biphenyls (PCBs) mixtures (dioxin-like compounds)[...]