This work proposed a novel and flexible immunosensor for highly selective and sensitive determination of cortisol in sweat. The flexible electrode was developed by transferring multi-walled carbon nanotubes (MWCNTs) film on polydimethylsiloxane (PDMS) substrate and subsequent electrochemical deposition of Au nanoparticles (AuNPs) on the MWCNTs surface. The obtained AuNPs/MWCNTs/PDMS electrode was then covalently immobilized with anti–cortisol monoclonal antibody (Anti-C_mab) and blocked with BSA. Scanning electron microscope confirmed that MWCNTs have been firmly combined with PDMS and AuNPs distributed uniformly on the surface of MWCNTs. The PDMS-based sensor possesses a good mechanical stability against stretching, bending and twisting, displaying stable electrochemical performance under deformation. After optimizing the analytical parameters, the developed immunosensor allowed a facile quantification of cortisol in the range of 1 fg/mL–1 μg/mL with a detection limit of 0.3 fg/mL. The cortisol immunosensor was further used to evaluate cortisol levels in human sweat, and the results corresponded closely with commercially available chemiluminescence immunoassay (CLIA) method. Results indicated that the new cortisol immunosensor could provide an effective tool for the noninvasive, point of care measurement of sweat cortisol levels and is promise to be a wearable biosensor for the healthy monitoring.

这项工作提出了一种新型灵活的免疫传感器，用于高选择性和灵敏地测定汗液中的皮质醇。柔性电极是通过在聚二甲基硅氧烷 (PDMS) 基板上转移多壁碳纳米管 (MWCNTs) 膜和随后在 MWCNTs 表面电化学沉积 Au 纳米颗粒 (AuNPs) 来开发的。然后将获得的 AuNPs/MWCNTs/PDMS 电极与抗皮质醇单克隆抗体（Anti- _Cmab) 并用 BSA 阻止。扫描电子显微镜证实，MWCNTs与均匀分布在MWCNTs表面的PDMS和AuNPs牢固结合。基于PDMS的传感器对拉伸、弯曲和扭曲具有良好的机械稳定性，在变形下表现出稳定的电化学性能。在优化分析参数后，开发的免疫传感器可以轻松量化 1 fg/mL–1 μg/mL 范围内的皮质醇，检测限为 0.3 fg/mL。皮质醇免疫传感器进一步用于评估人体汗液中的皮质醇水平，结果与市售的化学发光免疫测定（CLIA）方法密切对应。结果表明，新的皮质醇免疫传感器可以为无创、