A Colorimetric Immunoassay Based on g-C₃N₄@Fe₃O₄ Nanocomposite for Detection of Carcinoembryonic Antigen

Figure 2

(a) UV-vis absorption spectra of (A) sodium salicylate (6 mg/mL), (B) g-C₃N₄@Fe₃O₄ + HCl + sodium salicylate, and (C) g-C₃N₄@Fe₃O₄ + HCl + sodium salicylate + EDTA in 400 nm–700 nm (the inset: photograph of b and c); and (b) UV-vis absorption spectra of (A) Ab₁/CEA/Ab₂-g-C₃N₄@Fe₃O₄ and (B) Ab₁/CEA/Ab₂-Fe₃O₄ for 1 ng/mL CEA in phosphate buffer solution (pH 7.0).

(a)

(b)