Novel Label-Free Electrochemical Impedance Immunosensor Using a Three-Dimensional Flower-Shaped Gold Nanoparticle@Molybdenum(IV) Sulfide/Graphene Composite for the Ultrasensitive Determination of Procalcitonin

Abstract

Procalcitonin (PCT) is an inflammatory marker with significance in the early diagnosis of sepsis. The label-free electrochemical impedance immunosensor has good prospects for the determination of this disease marker due to its cost-effectiveness, high specificity and simple operation. However, developing an immunosensor for procalcitonin faces challenges due to the absence of satisfactory electrodes. Herein, a novel label-free electrochemical impedance immunosensor using the three-dimensional (3D) flower-shaped gold nanoparticle@molybdenum(IV) sulfide/graphene (Au NPs@MoS₂/graphene) composite is reported for procalcitonin. Under the optimal conditions, the immunosensor presents a linear response from 10 fg mL⁻¹ to 50 ng mL⁻¹ and an ultra-low detection limit of 2.3 fg mL⁻¹ for for procalcitonin. The excellent performance is due to the unique 3D flower-shape and the synergistic effect of Au NPs@MoS₂/graphene, generating a large surface area, high electrical conductivity, and increased immobilization of anti-PCT. Additionally, the immunosensor exhibits suitable specificity, stability, and reproducibility, and was used to determine procalcitonin in serum which may allow clinical screening and diagnosis of sepsis.

Keywords:

• Electrochemical impedance immunosensor
• label-free
• procalcitonin (PCT)
• three-dimensional (3D) flower-shaped gold nanoparticle@molybdenum(IV) sulfide/graphene (Au NPs@MoS₂/graphene) composite

Acknowledgments

The authors would like to thank Wei Xiao and Lili Zou for their help with the ethical review.

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

This work was supported by the Special Fund Project for Guangdong Academy of Sciences to Build First-Class Research Institutions by grant numbers 2021GDASYL-20210103027 and 2021GDASYL-20210302002; the Science and Technology Program of Guangzhou by grant numbers 202201011351, 2023A04J1400, and 202102021028; and the Natural Science Foundation of Guangdong Province by grant number 2021A1515010501.