Miniaturized microPADs as platforms for biochemical assays. (A) Calibration curve as generated from a colorimetric paper-based glucose assay. The data was fit with a linear trendline. Data points represent the mean of eight replicates and error bars represent one standard deviation of the mean. (B) Calibration curve for a colorimetric horseradish peroxidase (HRP) assay. The data was fit with a linear trendline. Data points represent a single replicate. (C) Photograph of the test zones after performing the HRP assays. Higher HRP concentrations produced higher color intensities in the test zones.