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

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.

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.

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.

Ultimately, Au nanoparticles/ g-C3N4 composite modified electrode can be a good platform for making electrochemical biosensor to diagnosis cancer in early stages.