Au nanorods/ g-C3N4 composite based biosensor for electrochemical detection of chronic lymphocytic leukemia

With the increasing incidence of cancer and the dramatic effect of early detection on treatment and increase patient's life, many efforts have been devoted to making sensitive diagnosis systems. DNA as a biomarker for diagnosis of different types of cancers at the early stages of illness has attracted much attention.

In this research novel electrochemical biosensor was developed using Pb2+ modified titanium phosphate nanoparticles and two DNA as capture probes. Considerable amounts of lead ions were mounted on the surface of titanium phosphate which produced the electrochemical signal. The surface of the biosensor electrode was modified by Au nanorods/ g-C3N4 composite. The functional group on the surface of g-C3N4, the chemical composition of tip, the morphology of composite and elemental composition of the composite were investigated by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Spectroscopy (EDS), respectively.

The peaks of C, N, and Au were observed in the EDS spectrum. The presence of Au peaks in the EDS spectrum confirmed the formation of composite from Au nanorods and g-C3N4 sheets. Whit this biosensor the linear range from 0.6 nM to 6.4 nM and the detection limit of 20 PM for target DNA was obtained.

Finally, it seems that the glassy carbon electrode modified with Au-nanorods/g-C3N4 composite is a good candidate for cancer diagnosis in the early stages.