Figure 5.

| Colorimetric detection of PSA in human serum by the MeLISA. A double-blind experiment was performed for PSA detection in serum samples. a, Photograph for the detection in 30 independent real samples using the MeLISA. b, Vertical scatter plots of the values of A_{620 nm}/A_{520 nm} for positive and negative samples. c, ROC curve for PSA in clinical samples. d, Coefficient of variation (CV) plotted with different patient numbers. The CV was obtained through three independent experiments and the marked cut-off was 15%.