Double-Amplified Electrochemiluminescence Immunoassay Sensor for Highly Sensitive Detection of CA19-9 Using a Ternary Semiconductor CdSSe
Zhengxing Gong, Baoyu Lu, Huan Wang, Xiang Ren, Xuejing Liu, Hongmin Ma, Dan Wu, Dawei Fan, Qin Wei
Abstract
In this paper, an electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of CA19-9 was constructed using ternary compound CdSSe nanoparticles as ECL emitter. The immunosensor employs Cu 2 S and gold-doped diindium trioxide (Au–In 2 O 3 ) nanocubes as coreaction accelerators to achieve a double-amplification strategy. In general, a hexagonal maple leaf-shaped Cu 2 S with a large surface area was selected as the template, and the in situ growth of CdSSe on its surface was achieved using a hydrothermal method. The presence of Cu 2 S not only inhibited the aggregation of CdSSe nanoparticles to reduce their surface energy but also acted as an ECL cathode coreaction promoter, facilitating the generation of SO 4 •– . Consequently, the ECL intensity of CdSSe was significantly enhanced, and the reduction potential was significantly lower. In addition, the template method was employed to synthesize Au–In 2 O 3 nanocubes, which offers the advantage of directly connecting materials with antibodies, resulting in a more stable construction of the immunosensor. Furthermore, In 2 O 3 serves as a coreaction promoter, enabling the amplification strategy for ECL intensity of CdSSe, thus contributing to the enhanced sensitivity and performance of the immunosensor. The constructed immunosensor exhibited a wide linear range (100 μU mL –1 to 100 U mL –1 ) and a low detection limit of 80 μU mL –1, demonstrating its high potential and practical value for sensitive detection of CA19-9.