Paper-based device enables smartphone detection of cancer biomarker

MicroRNAs are small non-coding RNA molecules that regulate gene expression. Aberrant expression of specific microRNAs is closely linked to cancer initiation and progression. In particular, miRNA-21 is significantly upregulated in numerous solid tumors including breast, lung, and colorectal cancers, making it a valuable diagnostic biomarker.

Conventional detection techniques such as quantitative PCR and microarray analysis require sophisticated instrumentation, specialized personnel, and lengthy procedures—limitations that prevent their deployment in resource-limited settings or for rapid point-of-care testing.

In this study, researchers developed a highly specific and sensitive colorimetric microfluidic paper-based analytical device for the rapid detection of miRNA-21. The sensing platform leverages the exceptional peroxidase-mimicking activity of synthesized Au@Pt NPs, which catalyze the TMB oxidation to generate a distinct blue color signal. The fabricated paper chip demonstrated excellent analytical performance with a wide linear detection range from 1 to 2,000 nmol/L and a remarkable detection limit of 0.25 nmol/L.

More importantly, the platform exhibited outstanding specificity in discriminating miRNA-21 from closely related miRNA sequences and maintained satisfactory detection accuracy in spiked human serum samples. These results collectively validate the great potential of nanozyme-based paper chip as a reliable, cost-effective tool for point-of-care cancer diagnosis and miRNA expression profiling.

The work entitled “Nanozyme-catalytic colorimetric microfluidic paper-based analytical device for rapid detection of miRNA-21” was published on Systems Microbiology and Biomanufacturing (published on Mar. 17, 2026).