The development of high sensitive alpha-fetoprotein immune-electrochemical detection method using an excellent...

A novel 3D C-based nano Cu₂[Fe(CN)₆]-C (C-CuFC) nanocrystals with unusually electrical-conductivity was synthesized based on reduced carboxylated graphene oxide (COOH-rGO) and copper nanoparticles (CuNPs) by using room temperature (RT) K₃[Fe(CN)₆]-solution growth. During the fabrication of C-CuFC electrode, rGO-COOH enabled the Cu²⁺ to tunnel the electrons, which contributed to form a 3D petal-liked structure (Flo.-C), meanwhile, the synthetic 3D Flo.-C induced crystal of the electroactive cubic CuFC-C in K₃[Fe(CN)₆] solution. Another, the [Cu(CN)₄]^2-, [Fe(CN)₆]^4- and quinones with high conductivity were produced, and the free Fe²⁺ and Cu²⁺ existed on solid (electrode)-liquid (electrolyte) interface also increased the electric signal directly, so this CuFC-C showed amazing electrochemical current, which was 29-folds larger than the current intensity of bare electrode. With attaching on electrode, CuFC-C nanomaterial can significantly improve the electrical conductivity of sensor. Impressively, such 3D-CuFC-C nanocrystals shows excellent anchoring ability toward the AFP-antibodies (Ab) ascribed to the unreduced COOH-group of CuFC-C. Hence, a 3D Ab/CuFC-C/GCE electrochemical immunosensor was constructed based the promising conductivity and biocompatibility. Meanwhile, the Ab/CuFC-C/GCE biosensor exhibited ultra-low detection limit (LOD: 1.40 × 10^-8 ng mL^-1) and a fast response time (0.4 min). Additionally, the developed biosensor displayed excellent stability and good recovery (92.07%-101.91%) for AFP in human serum. Therefore, this sensing-platform has great potential in rapidly and sensitively detecting biomarkers and the other race targets.