The Preparation Of Graphite-phase C₃N₄and Its Application In The Breast Cancer Tumor Markers Detection

Breast cancer is a common malignancy in women, its incidence has increasedyear by year. Early detection and treatment is very important for patients to prolongthe survival time and improve quality of life. This article shows the study of twocommon tumor markers of breast cancer——Vascular endothelial growth factor andRelated Gene fragment of Human epidermal growth factor receptor2(Cerb B-2), toseek for a simple, non-invasive, high-sensitivity detection methods. In recent years,with the development of nanotechnology, the researchers found that carbon nitride(C3N4) not only has excellent physical and chemical properties, but also has a broadapplication in the field of biology and potential applications in malignant tumors. Inthis paper, we make a preliminary study for the graphite-phase C3N4(g-C3N4)synthesis and its application in the detection of breast cancer tumor-associatedmarkers.In the first part, it preliminary studys the preparation of graphite-phase C3N4,which was prepared by polymorization of melamine molecules under hightemperature. The g-C3N4nano flake (g-C3N4-NF) was obtained by liquid exfoliatingof as-prepared bulk g-C3N4in water. At the same time, a fluorescent sensor based ong-C3N4-NF was developed for the detection of Breast cancer Cerb B-2related gene.Under the best conditions, it was found that the fluorescence intensity showed a finelinear relationship with the concentration of target DNA in the range from0.1nM to200nM, the regression equation was F=32.12Log(C)+32.76, and the regressioncoefficient (r) was0.9974. The detection limit was calculated to be0.02nM.In the second parts, bulk graphite-like carbon nitride (bulk g-C3N4) was preparedby polymorization of formamide under microwave. The water-soluble g-C3N4nanoflake (g-C3N4-NF) was obtained by liquid exfoliating of as-prepared bulk g-C3N4in water. At the same time, a fluorescent sensor based on g-C3N4-NF and nickingendonuclease assisted signal amplification was developed for the detection of Breastcancer Cerb B-2related gene. Under the best conditions, it was found that thefluorescence intensity showed a fine linear relationship with the concentration oftarget DNA in the range from5fM to0.1pM, the regression equation wasF=183.9774－1.5259C, and the regression coefficient (r) was0.9970, The detectionlimit was calculated to be0.2fM.In the third parts, the detection of Vascular endothelial growth factor (VEGF)was studied based on the g-C3N4-NF which was prepared by the second parts. At thesame time, a fluorescent sensor based on g-C3N4-NF and aptamer technology wasdeveloped for the detection of VEGF in Breast cancer. Under the best conditions, itwas found that the fluorescence intensity showed a fine linear relationship with theconcentration of VEGF in the range from10pM to80pM, the regression equationwas F=153.195-1.72804C, and the regression coefficient (r) was0.9857. Thedetection limit was calculated to be3.5pM.