Sensitive and electroactive surface development for electrochemical HER2 detection based on CS@CeO₂/MWCNTs nanocomposites

In this work, CS@CeO₂/MWCNTs nanocomposites (NC)-modified electrode surface was investigated as a highly electroactive surface for HER2 detection. The electrode modification was studied using CV and EIS. The detection was based on the resistance/current change caused by the movement of the [Fe (CN)₆]^3−/4− toward the conductive channels of the CS@CeO₂/MWCNTs/gold electrode, which was caused by the recognition of biomarker HER2. The synthesized NC simultaneously has the electroactive property of CeO₂ and a large surface coverage of 2.53 × 10⁻⁹ mol cm⁻², which results in the enhancement of the detection signal. Different concentrations of HER2 were analyzed using DPV. The immunosensor exhibited a detection range of 1 fg mL⁻¹ to 1 µg mL⁻¹, with a 0.01 pg mL⁻¹ LOD (S/N = 3) and a 0.03 pg mL⁻¹ LOQ for HER2. The immunosensor showed good sensitivity, specificity, and long-term storage stability for HER2, indicating significant promise for applications in early breast cancer diagnosis.