In this study, a novel integrated photoelectrochemical (PEC) sensor platform was proposed, utilizing an optical fiber (OF) as the working electrode for guided in situ light. A CdS quantum dots (QDs)/ZnO nanosheets (NSs) n-n heterojunction was quickly and easily constructed on the OF surface by successive ionic layer adsorption and reaction (SILAR). Au nanoparticles (NPs)@dsDNA as a capturing probe were modified on the CdS QDs/ZnO NSs@OF (CZ@OF). Due to the energy transfer between Au NPs@dsDNA and CdS QDs, the resultant opto-electrode has a lower background near zero, enabling the “signal-on” detection of biomarkers (interleukin-6 (IL-6) as a model). The OF-PEC biosensor demonstrated a wide linear range from 1 to 100 pg mL–1 with a regression coefficient (R2) of 0.9958 and an impressive detection limit (LOD) of 0.19 pg mL–1. More significantly, the proposed OF-PEC can be successfully used for the detection of IL-6 in serum samples from patients with pulmonary arterial hypertension, and it showed consistency and is more sensitive to trace concentrations compared to BD FACSCanto II flow cytometry used at the hospital. This holds significance for an early disease diagnosis. Therefore, the proposed OF-PEC not only achieves integration of the light source and sensing interface but also enables sensitive and accurate “signal-on” detection of IL-6. Furthermore, due to the flexibility and remote detection capabilities of OF, the application of OF-PEC is expected to be expanded more widely. This approach opens up possibilities for advances in PEC sensing.
Xiaoyan Wang,Hao Zheng,Huiling Chen,Bin Qiu,Yunliang Liu,Qing Ye
Interleukin-6 (IL-6) is a common proinflammatory cytokine and can be adopted as an important biomarker for several diseases including nasopharynx cancer, pancreatitis, infections, and cardiovascular. It is thus necessary to design an effective method for monitoring IL-6. Herein, by preparing gold nanoparticles/graphdiyne (Au/GRD) nanohybrid with simple electroless deposition as the sensing substrate and UiO-66 metal–organic frameworks/ferrocene (UiO/Fc) as the signaling-amplifier, a highly efficient sandwich-type electrochemical immunosensing (SEI) platform was proposed for IL-6 determination. The superior electrical properties, easy preparation, high surface area, and stability of Au/GRD make it a desirable substrate to immobilize the primary antibody of IL-6. Meanwhile, the unique structure of UiO-66 is beneficial to immobilizing the Fc probe and the secondary antibody. By optimizing experimental conditions, the Fc current obtained at the as-designed SEI platform increases along with IL-6 increase, and the related linearity is 0.5 pg ml−1–1200.0 pg ml−1 coupled with a low detection limit of 0.2 pg ml−1. It is expected the as-designed SEI platform based on Au/GRD and UiO/Fc shows potential applications for IL-6 analysis.
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