Fig. 1.

The dynamic range of digital PCR for miR-31 quantification in sputum of healthy individuals. The generated cDNA was diluted by twofold across seven orders of magnitude ranging from 1:8 to 1:512 and run for miRNA quantification by using digital PCR. a Each well of the samples and a negative template control (NTC) sample contained at least 10,000 droplets, suggesting that sputum could successfully be analyzed by digital PCR. b Intensity plots of DX100 QuantaSoft results for quantification of miR-31 in the serially diluted sputum samples. c Concentration represented by copy number of miR-31 per μl of PCR reaction measured by digital PCR assay. The error bars associated with each point represent the 95 % confidence interval. d Comparison of digital PCR and qRT-PCR using the serially diluted samples for quantification of miR-31 suggested high correlation of copy number obtained from digital PCR with expression levels determined by qRT-PCR. The dynamic range of quantification of miR-210 by using digital PCR and qPCR displayed similar results (data not shown)