Chemical-chemical redox cycling for improving the sensitivity of the fluorescent assay: A proof-of-concept towards DNA methylation detection

Overview on the Development of Electrochemical Immunosensors by the Signal Amplification of Enzyme- or Nanozyme-Based Catalysis Plus Redox Cycling

“…The electrochemical oxidation of the deposited Ag could produce a high electrochemical signal. In addition, such redox cycling systems have been widely used in optical bioassays, such as chemiluminescence [ 68 , 69 , 70 , 71 , 72 ], fluorescence [ 38 , 39 ], and SERS assays [ 43 ].…”

“…For this consideration, electrochemical immunosensors, DNA sensors, and aptasensors have been widely developed through enzymatic reaction plus redox cycling [ 34 , 35 , 36 , 37 ]. The integration of redox cycling and enzymatic catalysis can also be introduced into optical bioassays, including fluorescence [ 38 , 39 ], colorimetry [ 40 , 41 , 42 ], and surface-enhanced Raman scattering spectroscopy [ 43 ].…”

Optical Bioassays Based on the Signal Amplification of Redox Cycling

“…For instance, Zhang et al reported the fluorescence immunoassay of DNA methylation, in which the generated AA by ALP enzymatic catalysis could trigger chemical–chemical redox cycling and improve sensitivity [ 73 ]. At the same time, they also constructed a universal fluorescent sensing platform for DNA methylation detection based on AA-carried liposome and redox cycling amplification ( Figure 7 ) [ 74 ]. In this study, MnO 2 nanosheets were coated in situ on the surface of Ru(bpy) 3 2+ -loaded silica nanoparticles (Ru@SiO 2 @MnO 2 ).…”

“… Schematic illustration of ( a ) procedure of methylated DNA detection and ( b ) liposome assisted chemical–chemical redox cycling signal amplification for methylated DNA detection [ 74 ]. Copyright 2023 Elsevier B.V. …”