A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A

- A photoelectrochemical immunosensor based on ZnO NAs and NBs was fabricated.
- Cosensitized structure of ZnO NAs, CdS and Mn improved the photocurrent response.
- An excellent sensitivity and selectivity of NDPK-A detection was obtained.

Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn2+ displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL−1 and a wide linear range from 0.5 pg mL−1 to 10 μg mL−1. The R2 of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A.

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