Fig. 6

DPV profiles of the 1:1 nano-onion (NO)/MoS₂ nanosheet composite and MoS₂ nanosheet electrodes obtained with 1 µM methylene blue (MB; pH 7.0) in potassium chloride (KCl) in 1 ml volume flow cell. Figure a, c and d and Figure b, e, and f displays the sensing potential for HPV-16 and HPV-18, respectively. Figure a and b display average peak current calibrated from independent measurement of five distinct electrodes. Figure c through f showcase the DPV profile of a single electrode in sequential mode: without DNA, following probe DNA chemisorption, and after target DNA hybridization (5 ng/ml) for both NO/MoS₂ nanosheet composite and MoS₂ nanosheet electrodes