Au nanoparticles/g-C3N4 modified biosensor for electrochemical detection of gastric cancer miRNA based on hairpin locked nucleic acids probe

Objective: The annual incidence of cancer in the world is growing rapidly. The most important factor in the cure of cancers is their early diagnosis. miRNA, as a biomarker for early detection of cancer, has attracted a lot of attention. Methods: In this study, an electrochemical biosensor was developed to detect the amount of miR-106a, the biomarker of gastric cancer, by modifying a glassy carbon electrode (GCE) with a composite of graphitic carbon nitride and gold nanoparticles. Complementary DNA strand of miR-106a which modified with biotin was used as a probe. Nanoparticles of titanium phosphate modified with Streptavidin and zinc ions were used to generate the electrochemical signal in square wave voltammetry. To characterize the g-C3N4 functional group, the chemical composition of the titanium phosphate nanoparticles, the morphology and elemental composition of composite Fourier transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-Ray Spectroscopy (EDS) were used, respectively. Results: The peaks of C, N, and Au in EDS spectrum confirmed composite formation. The linear range and detection limit of the modified biosensor for miRNA-106a were obtained from 0.6 to 6.4 nM and 80 pM, respectively. Conclusion: Ultimately, Au nanoparticles/ g-C3N4 composite modified electrode can be a good platform for making electrochemical biosensor to diagnosis cancer in early stages.