An integrated magnetic/photothermal capillary immunochromatographic assay based on rambutan-like Fe3O4@Cu2−xS@PDA-Au nanoparticles

• Published in: Talanta (Oxford) 2025-03, Vol.284, p.127189, Article 127189
• Main Authors: Wang, Boyu, Peng, Tao, Jiang, Zhiyuan, Shen, Liyue, Dong, Jiahui, Song, Zhenfei, Qu, Jifeng, Dai, Xinhua
• Format: Article
• Language: English
• Subjects: Atomic magnetometer; Capillary immunochromatographic assay; Magnetic nanoparticles; Photothermal; Weak magnetic field detection
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.127189

Highly sensitive and quantitative detection of tumor markers is critically important for the early diagnosis and treatment of cancers. In this study, we propose a novel magnetic/photothermal dual-sensing capillary immunochromatographic assay (CICA) strategy for the sensitive detection of carcinoembryonic antigen (CEA). To achieve this, we developed a rambutan-like Fe3O4@Cu2−xS@PDA-Au core-shell heterostructure with a high photothermal conversion efficiency of 59.1 % and stable magnetic characteristics through a shell-by-shell method. Under optimal conditions, the dual-mode CICA platform exhibited good linearity within the ranges of 0.5–10 ng mL−1 and 0.005–2.5 ng mL−1 for photothermal and magnetic modes, respectively. Notably, leveraging the biosensing system based on the atomic spin-exchange relaxation-free (SERF) effect, the magnetic mode achieved an enhanced sensitivity with a limit of detection as low as 0.0021 ng mL−1, two orders of magnitude higher than that of the photothermal mode. The complementary detection of dual signals effectively overcomes the limitations of the single-signal mode. These findings provide new insights into the sensitive and quantitative detection of low-abundance CEA analytes, exhibiting enormous potential for the detection of other biomarkers. [Display omitted] •A magnetic/photothermal capillary immunoassay for CEA detection with a LOD of 0.0021 ng mL−1.•Fe3O4@Cu2−xS@PDA-Au has an excellent photothermal performance (η = 59.1 %).•Fe3O4@Cu2−xS@PDA-Au has a stable magnetic characteristic.•Self-developed atomic magnetometer biosensing platform is based on atomic spin SERF effect.•The magnetic detection of CEA with a response linear range of 0.005–2.5 ng mL−1.