Fig. 3

Characterisation of the wire electrochemical system. a Illustration of the wire electrochemical system. Gold, Ag/AgCl and platinum wires were used as the working, reference and counter electrode, respectively. All the wires were insulated by PVC insulation tape and left two exposed ends for sensing and connecting. All the wires were placed into a 3D-printed holder with anchors that can sit on a single well of a 96-well plate. b Electrochemical cleaning of the wire was performed using CV by repeat scanning from −0.3 to 1.5 V in 0.5 M sulphuric acid until typical clean gold cyclic voltammograms were observed. c Signal change at different SWV frequencies. MB peak signals of the LH aptamer were recorded under scans in different SWV frequency settings. We applied three concentrations (10, 100 and 1000 nM) of LH to investigate the signal change. Means ± s.d. from three independent experiments are shown (n = 3). d Square-wave voltammogram of wire-based LH aptamer sensor. All the curves were net currents obtained by performing SWV scan from −0.5 to 0 V, with 100-Hz frequency and 25-mV amplitude. Eight concentrations of LH were used: 0, 10, 50, 100, 200, 500, 1000 and 2000 nM. Error bars represent standard deviation (n = 3 replicates). e Concentration–response curve. The % of the signal change indicates that the change is a signal off model. The K_D was estimated to be 259 nM and the dynamic range was from 10 to 500 nM. Means ± s.d. from three independent experiments are shown (n = 3). Source data are provided as a Source Data file