Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles

<table>Nyquist diagram (−Im(<svg height="8.4250002" id="M103" style="vertical-align:-0.273pt" version="1.1" viewbox="0 0 8.5874996 8.4250002" width="8.5874996" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,8.013)"><path d="M475 445l-64 -69q-119 -128 -289 -280q27 6 81 -15q66 -26 102 -26q48 0 111 93l23 -19q-41 -84 -75.5 -116.5t-73.5 -32.5q-37 0 -147 53q-43 21 -63 7q-22 -15 -38 -41q-4 -7 -11 -7q-8 10 -8 26q0 38 47 83l292 273q-32 -5 -67 -1q-63 7 -105 7q-32 0 -53.5 -22
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</svg>) versus Re(<svg height="8.4250002" id="M104" style="vertical-align:-0.273pt" version="1.1" viewbox="0 0 8.5874996 8.4250002" width="8.5874996" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,8.013)"><path d="M475 445l-64 -69q-119 -128 -289 -280q27 6 81 -15q66 -26 102 -26q48 0 111 93l23 -19q-41 -84 -75.5 -116.5t-73.5 -32.5q-37 0 -147 53q-43 21 -63 7q-22 -15 -38 -41q-4 -7 -11 -7q-8 10 -8 26q0 38 47 83l292 273q-32 -5 -67 -1q-63 7 -105 7q-32 0 -53.5 -22
t-47.5 -67l-25 13q15 39 38 78q40 66 83 66q57 0 120 -12q52 -10 80 -10q29 0 67 42z" id="x1D467"></path></g>
</svg>)) for the non-Faradic impedance measurements (at −400 mV versus SCE, in PBS solution 10 mM pH 7.4) corresponding to the various layers grafted onto the gold electrode (system based on SAM): AUT, AUT-GA, AUT-GA-Neut., and AUT-GA-Neut.- Biot.ScAb. Spectra were obtained between 0.05 Hz and 100 kHz. Amplitude of ac voltage: 10 mV.</table>

Journal of Sensors

fig9

Figure 9

Figure 9: Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles 