3-Amino-1,2,4-triazole-derived graphitic carbon nitride for photodynamic therapy

Graphitic carbon nitride (g-C 3 N 4 ) has been shown as a promising visible-light photosensitizer for photodynamic therapy (PDT) application. Nevertheless, its therapeutic efficiency is limited by the low efficiency of visible-light utilization. To overcome this issue, 3-amino-1,2,4-triazole-derived graphitic carbon nitride nanosheets (g-C 3 N 5 NSs) are prepared for PDT application. The addition of nitrogen-rich triazole group into the g-C 3 N 4 motif significantly makes the light absorption of g-C 3 N 5 NSs red-shift with the band gap down to 1.95 eV, corresponding to a absorption edge at a wavelength of 636 nm. g-C 3 N 5 NSs generate superoxide anion radicals (O 2 •– ) and singlet oxygen ( 1 O 2 ) under the irradiation of a low-intensity white light emitting diode. Owing to the high efficiency of visible-light utilization, g-C 3 N 5 NSs show about 9.5 fold photocatalytic activity of g-C 3 N 4 NSs. In vitro anticancer studies based on the results of CCK-8 assay, Calcein-AM/PI cell-survival assay and photo-induced intracellular ROS level analysis in living HeLa cells demonstrate the potential of g-C 3 N 5 NSs as a low-toxic and biocompatible high-efficient photosensitizer for PDT.