Ultrasensitive biosensor for breast cancer screening

Background: MicroRNAs (miRNAs) are non-coding and single-stranded RNAs between 17-22 nucleotides that found in plants, animals and some viruses. Expression of miRNAs is changed in tumor compared to normal tissue and can be used as biomarkers for early detection of cancer diseases. Previous studies indicated that miRNA-155 plays an important role in the pathogenesis of breast cancer. Since the expression of miRNA-155 rises in patients with breast cancer, so it is considered as a breast cancer risk factor.Objective: We introduced an electrochemical biosensor for miRNA-155 detection with high sensitivity for breast cancer screening.Materials and Methods: Briefly, probe was immobilized through self-assembly onto a gold electrode. Then, target (miRNA-155) was hybridized to the probe. In the final step, silver nanoparticles were casted onto the modified gold electrode. Due to the oxidation of silver nanoparticles, significant electrochemical signal is produced.Results: The designed electrochemical biosensor provided an ultrasensitive detection of miRNA-155 at very low concentrations with the detection limit of 20 zeptomoles and a wide linear range from 20 to 2×109 zeptomoles. Moreover, such biosensor detected miRNA-155 in serum samples with satisfactory results.Conclusion: In the current work, a versatile, simple, cost-effective and highly sensitive electrochemical biosensor for the detection of miR-155 is presented. This sensor achieves an ultralow detection limit. Moreover, normal and cancerous serums were diagnosed by the biosensor successfully that is important for biomedical research and clinical POC applications.

Keywords:

Silver nanoparticles , miRNA-155 , Breast cancer , Biosensor