| 초록 |
Signal amplification is essential to obtain highly sensitive electrochemical immunosensors with low detection limits. There is signal amplification method that uses silver (Ag) enhancement (i.e., electroless Ag deposition). We reports a novel enzymatic Ag-deposition scheme combined with chemical–chemical redox cycling by reduced -nicotinamide adenine dinucleotide. When a solid surface is used for enzymatic Ag deposition, a label containing only an enzyme can be used. To construct a simple immunosensor, only ALP was used as a label, and a working electrode was used for electroless Ag deposition. In this study, an indium-tin oxide (ITO) electrode was used as a working electrode. Electroless Ag deposition occurred even on avidin- and BSA-modified ITO electrodes and enhanced Ag deposition was more evident. The novel scheme allows a higher Ag-deposition rate than a scheme using only enzymatic Ag deposition. Therefore, it can be applied for the highly sensitive detection of a cardiac biomarker, creatine kinase-MB. When the scheme was applied to the detection of CK-MB, a detection limit of ca. 10 pg mL-1. The enhanced Ag deposition obtained using CC redox cycling could be used to develop high-contrast immunohistochemical staining methods as well as highly sensitive immunosensors and DNA sensors. |
