Molybdenum blue mediated photothermal immunoassay for CEA detection based on Ag4P2O7@Ag nanocomposites

A photothermal immunoassay was built for tumor marker detection based on Ag4P2O7@Ag nanocomposites. Ag4P2O7@Ag nanomaterials were synthesized by precipitation-photoreduction reaction, and characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectra (XPS) and X-ray powder diffraction (XRD). Come about PO43− derived from Ag4P2O7@Ag under acidic conditions react with ammonium molybdate in the action of reductant generating molybdenum blue. The photothermal change is due to molybdenum blue solution depending on the concentration of carcinoembryonic antigen (CEA) in immunoassay. Under optimal conditions, there is a linear relation between ΔT and CEA concentration in the range of 1 pg mL−1–40 ng mL−1 with the detection limit of 0.33 pg mL−1. Meanwhile, the developed photothermal immunoassay displays preferable selectivity, repeatability, and stability. A novel photothermal immunoassay was constructed based on molybdenum blue. Molybdenum blue solution developed by Ag4P2O7@Ag nanocomposites reacted with ammonium molybdate under acidic conditions. Molybdenum blue has good photothermal stability and high photothermal conversion efficiency. Carcinoembryonic antigen in sample was detected sensitively by thermometer readout. [Display omitted] •The Ag4P2O7@Ag nanocomposites were synthesized, which can react with ammonium molybdate and produced molybdenum blue.•A novel photothermal immunoassay was built based on molybdenum blue for detection of CEA.•The sensitivity of immunoassay was improved due to high photothermal conversion efficiency of molybdenum blue.