BACKGROUND microRNA (miRNA) molecules are considered as biomarkers and have promising future for early-stage cancer diagnosis. Lawsone (Law) enriched carbon nanofibers (CNFs) were prepared via electrospinning process for the selective miRNA detection. Anti-miRNA molecules were attached on the CNFs immobilized screen printed electrodes (SPE) and used for the detection of miRNA molecules by observing guanine oxidation signal via differential pulse voltammetry (DPV) method. Three different miRNA molecules including the target (miRNA), single-base mismatched (SM.miRNA) and non-complementary (NC.miRNA) were hybridized with the previously attached anti-miRNA molecules (with guanine [PolyT(G)] and without guanine [PolyT(I)]) on the CNFs immobilized SPE surfaces. RESULTS Guanine oxidation signal decreased after the hybridization of miRNA with anti-miRNA molecules on CNF immobilized SPE surfaces. Guanine oxidation signal was not detected on the PolyT(I) attached samples, but the existence of guanine oxidation signal was clear detected after the addition of miRNA molecules on the previously attached PolyT(I). Because no hybridization of anti-miRNA molecules with the non-complementary miRNA (NC.miRNA) molecules occurred, the guanine oxidation signal was not significantly decreased after the interaction of NC.miRNA with the attached PolyT(G). Since there was no hybridization between the NC.miRNA molecules with the attached PolyT(I) on the SPEs, weak guanine peaks were detected at PolyT(I)-NC.miRNA samples as a result of the existence of residual NC.miRNA molecules on SPE after washing. CONCLUSIONS The measurement results confirm the enhanced selectivity of the miRNA molecules by using CNFs with SPEs and the developed biosensory system could be used to detect the specific RNA molecules. (c) 2021 Society of Chemical Industry (SCI).