Preparation of multiple-spectra encoded polyphosphazene microspheres and application for antibody detection

Polyphosphazene microspheres (PZS) multispectral encoded by fluorescence and surface enhanced Raman spectra (SERS) were prepared and used as solid phase carrier of capture antibody for antibody detection. A variety of fluorescent encoded polyphosphazene microspheres (FPZS) incorporating single and multiple fluorescent molecules were prepared. Multiple SERS encoded polyphosphazene microspheres (SPZS) were obtained by modification of different Raman reporters on the surface of PZS@Ag, which were fabricated with rough morphology through in situ deposition of Ag nanoparticles. Fluorescence and SERS spectral combined encoded polyphosphazene microspheres (FSPZS) were prepared by encoding of fluorescent molecules and SERS reporters. The optical signals in the two independent detection channels were separable and ensured the accuracy for the encoding method. Immunoassays of goat IgG, rabbit IgG and mouse IgG were performed by the as-prepared FPZS, SPZS and FSPZS as solid phase carrier of capture antibody and fluorescent labeled second antibody, using sandwich immunoassay method. The immunoassay results showed that the multiple-spectra encoded microspheres have stable and distinguishable encoding signals, large encoding volume and multiplexed analytical capability in sandwich immunoassays.