Figure 3 | Scientific Reports

Figure 3

From: A handheld platform for target protein detection and quantification using disposable nanopore strips

Figure 3

Measuring and modeling the fraction of tagged events as a function of HGD65 target-to-scaffold/fusion ratio. (a) EMSA assay showed increasing fraction of target-bound scaffold/fusion molecules as HGD65 antibody concentration increases, using a 217 bp/PNA-peptide detection reagent. (b) The data are the tagged fraction of recorded events with the 95% confidence interval \((Q\pm 1.96\sqrt{Q\mathrm{(1}-Q)/N})\) at six different target-to-scaffold/fusion ratios X. The fitted three-parameter model Ftag(X) is defined in Eq. (1). The reagent for each ratio X was measured sequentially on the same pore (P15, Supplementary Table S19), with 5 minutes of event-free buffer only recording in between reagents. The number of events N and ordered recording periods for each X were: (i) X = 0, N = 475 in 7 min, (ii) X = 2.8, N = 819 in 17 min, (iii) X = 1.4, N = 685 in 14 min, (iv) X = 0.7, N = 615 in 13 min, (v) X = 0.35, N = 516 in 10 min, (vi) X = 3.7, N = 663 in 16 min, (vii) X = 7.4, N = 783 in 14 min. Model fitting error was 2.2% using a normalized root-mean-square (Supplementary Table S20). The Q data for X = (0.35, 0.7, 1.4) are sufficiently below saturation to permit concentration estimation, as described in the main text. The results are estimated (0.53 ± 0.07, 1.4 ± 0.05, 2.8 ± 0.3) nM compared to knowns (0.7, 1.4, 2.8) nM (Supplementary Table S21). Thus, a single pore nominally has a 2-log detection range and 1-log quantitative range.

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