Fig. 2.
(A) Typical cyclic voltammograms of (a) bare SPE (b) PPy/SPE, (c) n-SiNPs/PPy/SPE and (d) MC1R-Ab/n-SiNPs/PPy/SPE in 1 × PBS solution at pH 7.4 containing 1 mM[Fe(CN)6]3−, 0.1 M KCl, and 100 μM EDTA at scan rate 50 mV s−1. (B) Effect of the cell collection method (Tyrpsin–EDTA, by using 0.25% Trypsin–EDTA; scraped, by using a cell scraper; EDTA, by using 2% EDTA solution in 1 × PBS) on signal current for different SK-MEL-2 cell loads. CV responses of the immunosensor with (C) and without (D) MC1R-Abs in the absence (a) and in the presence of (b) 7500 SK-MEL-2 cells/2.5 mL and (c) 7500 WM-35 cells/2.5 mL. Experimental parameters: 1 × PBS solution at pH 7.4 containing 1 mM [Fe(CN)6]3−, 0.1 M KCl, 100 μM EDTA, room temperature; scan rate 50 mV s−1.
