SiMBiT sensing measurements according to the protocol described in Figure4, carried out in: c) in PBS added with CD55 at 10 zm. The leftmost panels feature the schematics of the gate pillars illustrating the chem-SAM, the capturing recognition elements (anti-MUC1, anti-CD55, b-BRAS), and their affinity ligands; the negative control experiments involve a gate functionalized with BSA that is exposed to all the three markers (KRAS, MUC1, and CD55) at a concentration of 10 10−9m. The central panels show the sensing currentI(red curves) and the baselineI0(blue curves) during the cycling involving the measurement of 20 transfer characteristic curves (IDvsVGSin the 0 to −0.5 V range at fixedVD= −0.4 V measured in deionized water). The rightmost panels give the current relative change (I−I0)/I0= ΔI/I0vs cycles (topx-axis) and time (bottomx-axis). The current is measured in deionized water and the ΔI/I0data-points are taken atVGS= −0.5 V andVD= −0.4 V, one for each of the 20 cycles. The whole cycling takes 2.5 min. The data points are the average values over three replicates taken on three different gates. The blue dots are evaluated after incubation in the reference fluid (PBS), while the red ones are measured after incubation in PBS added with a single marker. The gray shaded area is the standard deviation over the three replicates. The black dashed lines in the rightmost panels are the relative current changes measured on the lateral gate serving as reference electrode. The limit-of-identification (LOI) level is also shown as a dashed-dotted black line (see text for details).
