Electrochemiluminescence ultrasensitive immunoassay for carbohydrate antigen 125 based on AgInS2/ZnS nanocrystals

• Published in: Analytical and bioanalytical chemistry Vol. 413; no. 8; pp. 2207 - 2215
• Main Authors: Yin, Min, Wang, Yan, Gao, Xuwen, Du, Shichao, Cheng, Yan, Yu, Shuai, Zou, Guizheng, Xue, Fumin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2021; Springer Nature B.V
• Subjects: Analytical Chemistry; Antigens; Biochemistry; Biocompatibility; Carbohydrates; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Crystals; detection limit; early diagnosis; Electrochemiluminescence; electrochemistry; Food Science; Immunoassay; immunoassays; Immunosensors; Laboratory Medicine; Monitoring/Environmental Analysis; Nanocrystals; Ovarian cancer; ovarian neoplasms; Photoluminescence; Photons; Research Paper; Valence band; water solubility; ZnS NCs; AgInS; Carbohydrate antigen 125 (CA125); Electrochemiluminescence (ECL); Immunosensor
• ISSN: 1618-2642; 1618-2650; 1618-2650
• DOI: 10.1007/s00216-021-03191-0

We developed a near-infrared (NIR) electrochemiluminescence (ECL) immunosensor for sensitively and selectively determining carbohydrate antigen 125 (CA125) with toxic-element-free and environmental-friendly AgInS 2 /ZnS nanocrystals (NCs) as tags. The core/shell-structured AgInS 2 /ZnS NCs not only can be conveniently prepared via an aqueous synthetic procedure, but also has high photoluminescence quantum yield (PLQY) of up to 61.7%, highly monodispersed, water-soluble, and desired biological compatibility. As AgInS 2 /ZnS NCs can be oxidized via electrochemically injecting holes into their valence band at + 0.84 V, both the monodispersed AgInS 2 /ZnS NCs in solution and the surface-confined AgInS 2 /ZnS NCs immobilized in sandwich-typed immuno-complexes with CA125 as analyte can exhibit efficient oxidative-reduction ECL around 695 nm under physiological conditions with the presence of tri-n-propylamine (TPrA). The ECL intensity from the AgInS 2 /ZnS NCs immobilized in sandwich-typed immuno-complexes increases linearly and selectively with an increased concentration of CA125 from 5 × 10 −6 to 5 × 10 −3  U/mL, and limit of detection (LOD) was 1 × 10 −6  U/mL (S/ N  = 3). This reliable platform can provide an effective detection method in the early diagnosis and treatment of ovarian cancer. Graphical abstract