RNA-on-Nanowire: A Metallic Nanowire Biosensor for Ultrasensitive MiRNA Detection at Single-Nucleotide Resolution

MicroRNAs (miRNAs) are vital in regulating biological processes and serve as effective biomarkers for tumor diagnosis in clinical trials. However, current miRNA detection approaches either lack sensitivity and selectivity among similar sequences in complex biofluids, or require cumbersome instruments and tedious operations, making convenient miRNA testing challenging, especially in the field of point-of care clinical diagnosis. Here, an ultrasensitive single metallic nanowire-based biosensor with stem-loop probes modified by redox substances for one-step miRNA detection with single base detection resolution (RNA-on-Nanowire) is presented. Using miRNA-16 as a proof-of-concept, the developed RNA-on-Nanowire biosensor demonstrates high sensitivity with a wide detection range of 10 am-1 pm and a low limit of detection (LOD) of 0.54 am in mock samples. Furthermore, the biosensor showed excellent selectivity to miRNA-16 among various miRNAs with the detection capability of single base substitution. Moreover, the successful detection of miRNA in serum samples with an LOD of 0.89 am suggest the great potential of the RNA-on-Nanowire biosensor for clinical applications. Overall, the presented RNA-on-Nanowire biosensor holds advantages in small sample consumption, high sensitivity, high specificity, and excellent portability which provides a promising strategy to meet the point-of-care testing demand for diagnosis and prognosis of various genetic diseases. This work presents an ultrasensitive single metallic nanowire-based biosensor with stem-loop probes modified by redox substances for one-step miRNA detection (RNA-on-Nanowire). The developed biosensor demonstrates high sensitivity with a wide detection range, and excellent selectivity at the single-nucleotide resolution in serum samples. This promising strategy offers great potential for the diagnosis and prognosis of various genetic diseases.image