Figure 3
The results of cotton-based diagnostic device analysis of nitrite, urobilinogen, BSA and uric acid in a buffer system and clinical sample.
We diluted purified nitrite (0.156 ~ 2.5 mM, 2-fold serially dilution) for A, BSA (1.875 ~ 30 μM, 2-fold serially dilution) for B, urobilinogen (7.8 ~ 125 μM, 2-fold serially dilution) for C, uric acid (100 ~ 1600 μM, 2-fold serially dilution) for D with PBS buffer and urobilinogen (7.8 ~ 125 μM, 2-fold serially dilution) for E with urine sample. After data readout (via desktop scanner to scan the reacting test pad and turn the colorimetric output signal into a grayscale value to analyze the color intensity via the graphics processing software, ImageJ), we obtained sensitivity by parabola (nitrite and uric acid assays) and a linear (BSA and urobilinogen assays) equation to generate an Orginpro 8 curve fitting. This figure shows the calibration plot for the mean intensity (I) of the colorimetric results for reagent compound reaction in our cotton-based diagnostic device versus the amount of the substrate absorbed by each test pad. Each value is the mean of ten replicates (samples number N = 10) and the error bars represent the standard deviations of the measurements. The R2 values of the curve fit to the data using the equation are nitrite: 0.99, BSA: 0.98, urobilinogen: 0.95, uric acid: 0.99 and urobilinogen in clinical sample: 0.95 in this study.
