Electrical signal of the SiNW-FET chip
immobilized with 6×-histidine
peptide after incubation of nanowire channels with 150 mM BTP buffer
(black curve) and 1 μg/mL rabbit anti-6×-His antibody (IgG)
in 150 mM BTP buffer (red curve), followed by ∼6 μg/mL
R18 RNA in 150 mM BTP buffer (blue curve). The conductance significantly
reduces with the presence of R18, although it can (A) decrease, (B)
increase, or (C) even remain mostly unchanged after IgG detection.
Insets are their corresponding statistical data as ΔV = mean ± standard deviation (n =
5) after detecting rabbit IgG (ΔVIgG-BTP) and R18 RNA (ΔVR18-BTP) (A: ΔVIgG-BTP = 320 ±
203 mV, ΔVR18-BTP = 626 ±
64 mV; B: ΔVIgG-BTP = −237
± 114 mV, ΔVR18-BTP =
736 ± 58 mV; C: ΔVIgG-BTP = 1 ± 49 mV, ΔVR18-BTP = 395 ± 38 mV). (D) Total statistical data
for signal amplification of this direct immunoassay by the aptamer
as ΔV = mean ± standard deviation (n = 15) (ΔVIgG-BTP = 28 ± 268 mV, ΔVR18-BTP = 719 ± 110 mV).