An electrochemical DNA detection method has been developed for the sensitive quantification of an amplified 406-base pair human cytomegalovirus DNA sequence (HCMV DNA). The assay relies on (i) the hybridization of the single-stranded target HCMV DNA with an oligonucleotide-modified Au nanoparticle probe, (ii) followed by the release of the gold metal atoms anchored on the hybrids by oxidative metal dissolution, and (iii) the indirect determination of the solubilized AuIII ions by anodic stripping voltammetry at a sandwich-type screen-printed microband electrode (SPMBE). Due to the enhancement of the AuIII mass transfer by nonlinear diffusion during the electrodeposition time, the SPMBE allows the sensitive determination of AuIII in a small volume of quiescent solution. The combination of the sensitive AuIII determination at a SPMBE with the large number of AuIII released from each gold nanoparticle probe allows detection of as low as 5 pM amplified HCMV DNA fragment.

Cold Atmospheric Plasmas (CAPs) are increasingly used for biomedical applications, their various reactive components must be then better determined. We demonstrate that peroxynitrite (ONOO−) is effectively a major reactive species generated by CAPs.

The electroanalytical technique Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) has been extended by applying stripping chronopotentiometry (SCP) as the re-oxidation stage in the determination of the free concentration of Zn(2+), Cd(2+) and Pb(2+). This new approach, called AGNES-SCP, has been implemented with screen-printed electrodes (SPE) and the standard Hanging Mercury Drop Electrode (HMDE). Clear advantages of this variant have been shown: (i) the easy resolution of the peaks of different metals present in mixtures and (ii) the sparing of blanks. A rigorous computation of the faradaic charge along the SCP stage takes into account the contribution of other oxidants, which can be efficiently measured at the end of the deposition stage of AGNES. The free Cd concentration determined in an oxalate solution at pH 6 with an HMDE as the working electrode agreed well with values obtained with a Cd Ion Selective Electrode. The free metal concentration measured using an SPE for the system Cd and nitrilotriacetic acid (NTA) at pH = 4.8 also conformed well with Visual MINTEQ results.