FIGURE 4.

Schematics of (A) Synthetic Route for Antibody-Modified Fe₃O₄@Ag Magnetic Tags and diagram of the Magnetic SERS Strip for Detecting Two Respiratory Viruses (Wang et al., 2019). Copyright 2019, American Chemical Society (B) Analyte Detection Using Magnetic Nanozyme-Based LFIA Strips (Kim et al., 2017b). Copyright 2019, American Chemical Society (C) Bio-separation of target molecules from blood plasma by functional Fe₃O₄ magnetic nanoparticles (MNPs), followed by the MNP mediated nano-SPR assay. The application of MNP results in an enhancement of the LSPR shift at peak absorption wavelength (Tang et al., 2013). Copyright 2017, American Chemical Society (D) Assay for the detection of tumor-associated plasma (and serum) p53 autoantibody. A neutravidin-modified screen-printed carbon electrode was functionalized with biotinylated p53. Serum/plasma samples containing p53-specific autoantibody were then incubated onto the electrode surface followed by the incubation with IgG/Au−NPFe₂O₃NC nanocatalyst. The surface-attached Au−NPFe₂O₃NC nanocatalyst catalyzed the oxidation of TMB in the presence of H₂O₂ and produced a blue-colored complex product (naked eye), which turned yellow after the addition of an acid to the reaction media. The level of p53 autoantibody was detected via measuring the intensity (UV−vis) and amperometric current generated by the yellow product (Masud et al., 2017b). Copyright 2017, American Chemical Society.