Biosens Bioelectron 2019 May 18;133:94-99. Epub 2019 Mar 18.
Institute of Surface Analysis and Chemical Biology, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China; College of Optoelectronics Technology, Chengdu University of Information Technology, Chengdu 610225, China. Electronic address:
Protein-inorganic nanoflowers have been extensively used for sensing and biosensing applications by virtue of the signal enhancement of protein component---enzyme. Can the inorganic component of protein-inorganic nanoflowers be employed to amplify signal transducing for enzyme-free detection? In this work, a new kind of BSA-antibodies-copper phosphate hybrid nanoflowers (BSA-Ab-Cu(PO)) has been prepared by one-pot biomimetic mineralization process as signal enhancer for enzyme-free electrochemical immunoassay. C-reactive protein (CRP) has been chosen as a model biomarker. To the best of our knowledge, it is the first trial using the inorganic component---phosphate ions of BSA-Ab-Cu(PO) for transducing electrochemical readout, which features the following advantages: (1) the three-dimensional hierarchical porous nanoflower morphology with a high specific surface area could load more antibodies, and BSA for blocking non-specific sites, greatly increasing the sensitivity of the fabricated immunosensors, (2) the Cu(PO) hybrid nanoflowers can supply a huge amount of phosphate anions to react with molybdate yielding molybdophosphate precipitates and generating redox currents for more robust enzyme-free electrochemical signal readout. The fabricated immunosensor has exhibited good detection performance with a linear range of 5 pg/mL-1 ng/mL and a limit of detection of 1.26 pg/mL. Moreover, our method has presented good feasibility for clinical sample analysis.