Electrochemical detection of serum miRNA-155 for breast cancer screening

MicroRNAs (miRNAs) are a class of short, approximately 19–25 nucleotides that regulate the expression of a wide variety of genes. miRNAs has garnered considerable attention in the field of disease biomarkers and exploited as new kinds of molecular targets for early detection and diagnosing of cancers because of their remarkable stability in blood, low cost, minimal invasiveness and their characteristic expression in different diseases. Recently, in studies that focused on the association between miRNAs and tumors, abnormal expression of miRNA-155 in patients with breast cancer has have attracted considerable attentions. As an oncogene, high expression of miRNA-155 was considered as a breast cancer risk factor. As a result, label-free, rapid, and sensitive detection for miRNA-155 is of great significance. In this study, we designed a sensitive and label-free assay for detection of miRNA-155 using positively charged silver nanoparticles. Briefly, thiolated 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. 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.

کلیدواژه ها:

Silver nanoparticles ، miRNA-155 ، Breast cancer ، Biosensor