Fig. 4. Nyquist plots of impedance spectra by using different modified electrodes in 5 mM [Fe(CN)₆]^3−/4−. (a) Bare GCE; (b) Au NPs/IL-MoS₂/chitosan/GCE; (c) anti-CRP/Au NPs/IL-MoS₂/chitosan/GCE; (d) BSA/anti-CRP/Au NPs/IL-MoS₂/chitosan/GCE; (e) CRP/BSA/anti-CRP/Au NPs/IL-MoS₂/chitosan/GCE; (f) Ir NPs/GO-DN labled-anti-CRP/CRP/BSA/anti-CRP/Au NPs/IL-MoS₂/chitosan/GCE.