N-(4-Aminobutyl)-N-ethylisopropanol and Co2+ Dual-Functionalized Core-Shell Fe3O4@Au/Ag Magnetic Nanomaterials with Strong and Stable Chemiluminescence for a Label-Free Exosome Immunosensor

Recently, magnetic beads (MBs) are moving toward chemiluminescence(CL) functional magnetic nanomaterials with a great potential forconstructing label-free immunosensors. However, most of the CL-functionalizedMBs suffer from scarce binding sites, easy aggregation, and leakageof CL reagents, which will ultimately affect the analytical performanceof immunosensors. Herein, by using core-shell Fe3O4@Au/Ag magnetic nanomaterials as a nanoplatform, a novel N-(4-aminobutyl)-N-ethylisopropanol (ABEI)and Co2+ dual-functionalized magnetic nanomaterial, namely,Fe3O4@Au/Ag/ABEI/Co2+, with strongand stable CL emission was successfully synthesized. Its CL intensitywas 36 and 3.5 times higher than that of MB@ABEI-Au/Co2+ and ABEI and Co2+ dual-functionalized chemiluminescentMBs previously reported by our group, respectively. It was found thatthe excellent CL performance of Fe3O4@Au/Ag/ABEI/Co2+ could be attributed to the enrichment effect of the Au/Agshell and the synergistic enhance effect of the Au/Ag shell and Co2+. A related CL mechanism has been proposed. Afterward, basedon the intense and stable CL emission of Fe3O4@Au/Ag/ABEI/Co2+, a sensitive and effective label-freeCL immunosensor for exosome detection was established. It exhibitedexcellent analytical performance with a wide detection range of 3.1x 10(3) to 3.1 x 10(8) particles/mL anda low detection limit of 2.1 x 10(3) particles/mL, whichwere better than the vast majority of the reported CL immunosensors.Moreover, the proposed label-free CL immunosensor was successfullyused to detect exosomes in human serum samples and enabled us to distinguishhealthy persons and lung cancer patients. It has the potential tobe a powerful tool for exosome study and early cancer diagnosis.

Automated summary

A novel magnetic nanomaterial, Fe3O4@Au/Ag/ABEI/Co2+, with strong and stable chemiluminescence (CL) emission was synthesized. A label-free CL immunosensor for exosome detection was established based on this nanomaterial, exhibiting excellent analytical performance. The immunosensor has the potential for early cancer diagnosis.