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

Objective(s): 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 detection of cancer in early stage, has attracted a lot of attention. Methods: In this research, an electrochemical biosensor was designed to detect the amount of miR-106a, the biomarker of gastric cancer, by modifying a glassy carbon electrode (GCE) with a composite of g-C3N4 and Au 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 identify the g-C3N4 functional group, the chemical composition of the titanium phosphate nanoparticles, the morphology and elemental composition of composite Fourier transform Infrared Spectroscopy, X-Ray Diffraction, Field Emission Scanning Electron Microscopy, and Energy Dispersive X-Ray Spectroscopy were used, respectively. Results: The peaks of C, N, and Au in EDS spectrum confirmed composite formation. The linear range of the modified biosensor for miRNA-106a was obtained from 0.6 to 6.4 nM. The detection limit was calculated 80 pM. Conclusions: Ultimately, Au nanoparticles/ g-C3N4 composite modified electrode can be a good platform for making electrochemical biosensor to diagnosis cancer in early stages.