An electrochemiluminescence immunosensor based on multipath signal catalytic amplification integrated in a Cu2+–PEI–Pt/AuNC nanocomposite

• Published in: Analyst (London) 2023-07, Vol.148 (14), p.3354-3358
• Main Authors: Wang, Haijun, Song, Yuhang, Chai, Yaqin, Ruo Yuan
• Format: Article
• Language: English
• Subjects: Amplification; Copper; Decomposition; Dissolved oxygen; Electrochemiluminescence; Gold; Hydrogen peroxide; Immunosensors; Nanocomposites; Platinum; Polyethyleneimine; Reducing agents
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d3an00721a

Here, the nanocomposite Cu2+–PEI–Pt/AuNCs with multipath signal catalytic amplification for a peroxydisulfate–dissolved oxygen electrochemiluminescence (ECL) system was prepared to fabricate a sensitive ECL immunosensor. Using polyethyleneimine (PEI), a linear polymer, as the reductant and template, Pt/Au nanochains (Pt/AuNCs) were prepared. Abundant PEI would adsorb on the surface of Pt/AuNCs via Pt–N or Au–N bonds, and further coordinate with Cu2+ to give the final nanocomposite Cu2+–PEI–Pt/AuNCs which possessed multipath signal catalytic amplification for the ECL of the peroxydisulfate–dissolved oxygen system in the presence of H2O2. First, PEI, as an effective co-reactant, could directly enhance the ECL intensity. Second, Pt/AuNCs could not only act as a mimicking enzyme to promote the decomposition of H2O2 to produce more oxygen in situ, but also act as an effective co-reaction accelerator to facilitate the generation of more co-reactive intermediate groups from peroxydisulfate, resulting in an obviously enhanced ECL signal. Then, Cu2+ could also accelerate the decomposition of H2O2 to produce more oxygen in situ, leading to a further improvement of the ECL response. Using Cu2+–PEI–Pt/AuNCs as a loading platform, a sandwiched ECL immunosensor was fabricated. As a result, the obtained ECL immunosensor possessed an ultra-sensitive detection performance for α-1-fetoprotein, providing effective information on the diagnosis and treatment of related diseases.