Design of electrochemical nanobiosensor to detect microRNA-423-5p as a risk factor of oral cancer

Abstract

Oral cancer is one of the most common cancers and one of the top ten causes of death worldwide. Among oral cancers, squamous cell carcinoma (OSCC) has the highest prevalence and low survival rate. MicroRNAs are short non-coding RNAs that regulate gene expression and play a very important role in tomogenesis. Many studies have been conducted on the role of different microRNAs in OSCC tissue. Several studies show that miR-423-5p is increased in the saliva of OSCC patients. The results of the studies indicate that the high expression of miR-423-5p is not only related to the growth of human oral cancer, but it is also a possible option as a diagnostic marker of OSCC in the future. On the other hand, the ability to detect many cancers in the early stages is of particular importance to improve patient outcomes in terms of morbidity and mortality. The use of new nano biosensors as a new and modern solution can be used for early detection of this cancer. To prepare DNA-based biosensor, we used glassy carbon electrode modified with gold nanoparticles along with CTAB template and sulfuric acid. In this research, a specific oligonucleotide is fixed on a glassy carbon electrode modified with gold nanoparticles. Cyclic voltammetry and differential pulse voltammetry techniques were used to monitor the electrochemical behavior of the DNA-based biosensor. Field emission scanning electron microscope was used to examine the morphological pattern and structural characteristics of the surface of the glassy carbon electrode modified with gold, after fixing the probe and after the hybridization reaction. Gold nanostructure was investigated in order to fix specific probe on its surface and detect hybridization with different sequences with high sensitivity. In this research, a thiolated oligonucleotide probe was designed based on reverse complementary sequence. Electrochemical measurements were performed in a conventional three-electrode cell. After depositing the gold nanostructure on the surface of the glassy carbon electrode, the DNA probe was fixed on the surface of the modified electrode, and in order to deactivate the oligonucleotide-free sites on the prepared electrode, mercaptoethanol solution was used. Hybridization with the complementary sequence of the target was done in order to identify the specific sequence. According to the results, the electrode modified with gold nanoparticles effectively detects the complementary sequence of the target through the hybridization process after stabilizing the DNA probe encapsulated inside the dendrimeric silicate mesopress compounds (KCC-1). The designed biosensor showed good selectivity in detecting the complementary DNA sequence compared to the non-complementary sequence. The biosensor based on engineered DNA in this research has the ability to detect the complementary sequence in the linear range of 1-10 × 1 M to 1 × 10-12 M, and its lowest detection limit is 1 picoM (M 1 × 10-12 ) Obtained.