Early cancer detection based on guanine oxidation consequent to the hybridization between miRNA-21 and it s inosine substitute capture probe

Cancer is a one of the main cause of death in the world that its early diagnosis plays a critical role towards effective treatment outcome and patient survivals. Today biomarkers can provide a non-invasive approach for early detection of various types of cancers. These biological molecules give information about creation and development of cancer and can be measured simply, rapidly, reliably and cost effectively in body fluids. In this report, we used the advantage of nanomaterials along with the specificity of the nucleic acids to increase the sensitivity of miRNA biosensor. For this purpose, the glassy carbon electrode was modified by reduced grapheme oxide and gold nanoparticles (AuNPs/rGO/GC electrode). This electrode was modified with a self-assembled monolayer of mercapto acetic acid (MAA), as a linker to immobilization of the inosine substituted ss-DNA capture probe on the electrode surface (ss-DNA/MAA/AuNPs/rGO/GC electrode). The immobilization of mentioned components on ss-DNA/MAA/AuNPs/rGO/GC electrode surface was monitored by cyclic voltammetry (CV) method. The hybridization between ss-DNA and miRNA-21 was performed and oxidation of guanine during the hybrid formation was evaluated by differential pulse voltammetry (DPV). The observation of peak current increasing is related to hybridization process. We were able to directly detected 200 pM of synthetic miRNA-21 in buffer solution without the need of PCR and labeling reaction. Consequently this test will be valuable for sensitive, selective and label-free detection of miRNA and it s feasible for miRNA detection in serum and other biological samples.

کلیدواژه ها:

Reduced graphene oxide ، Gold nanoparticles ، miRNA-21 ، Differential pulse voltammetry ، Early cancer detection