A Novel Aptasensor Based on Graphene/Graphite Carbon Nitride Nanocomposites for Cadmium Detection with High Selectivity and Sensitivity

Aptamers as new modes of detection have strong affinity and specificity for targets. A novel sensor was developed by constructing a composite system of specific aptamers and reduced graphene oxide (rGO)/graphitic carbon nitride (g-C₃N₄) (GCN) for detecting the cadmium cation. Attributed to the incorporation of rGO and aptamers with designed terminal groups as well as the delicate bonding of aptamers with g-C₃N₄, this electrochemical biosensor exhibited good sensitivity, specificity, reproducibility, and stability for Cd²⁺ detection. The linear calibration curves range from 1 nM to 1 μM and from 1 μM to 1 mM, and the limit of detection (LOD) was calculated to be 0.337 nM. The practical application of the proposed method was also verified in the real sample.