A novel synergistic enhanced chemiluminescence achieved by a multiplex nanoprobe for biological applications combined with dual-amplification of magnetic nanoparticles

A multiplex nanoprobe (CuS/DNA/Au/DNA/MNP) achieving a novel synergistic enhanced chemiluminescence (SECL) system is applied in a signal amplified bioassay strategy based on magnetic nanoparticles (MNPs) acting as both DNA molecular carriers and reporter labels, and further amplifying the signals by dual-amplification (DNA amplification and metal ions amplification). In this study, a luminol–H2O2–Cu2+–Fe3+ SECL system is proposed for the first time, which is achieved by a multicomponent nanoparticle probe and significantly intensifies the CL signal compared to monometallic Cu2+ or Fe3+ catalyst. The combination of the remarkable sensitivity of the SECL method with the amplification of MNPs achieves the detection of specific DNA sequences and Ramos cells as low as 6.8 aM and 56 cells mL−1, respectively, which is one of the most sensitive approaches for bioassays. In addition, the strategy is able to differentiate between Ramos target cells and CEM control cells based on the high specificity of the aptamer for Ramos cells, indicating the wide applicability of it for diseased cell detection.