An optical aptasensor for real-time quantification of endotoxin: From ensemble to single-molecule resolution

Pancheng Zhu, Vasileios Papadimitriou, Jeanne E. van Dongen, Julia Cordeiro, Yannick Neeleman, Albert Santoso, Shuyi Chen, Jan C.T. Eijkel, Hammin Peng, Loes Segerink* (Corresponding Author), Alina Rwei* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

12 Citations (Scopus)
53 Downloads (Pure)


Endotoxin is a deadly pyrogen, rendering it crucial to monitor with high accuracy and efficiency. However, current endotoxin detection relies on multistep processes that are labor-intensive, time-consuming, and unsustainable. Here, we report an aptamer-based biosensor for the real-time optical detection of endotoxin. The endotoxin sensor exploits the distance-dependent scattering of gold nanoparticles (AuNPs) coupled to a gold nanofilm. This is enabled by the conformational changes of an endotoxin-specific aptamer upon target binding. The sensor can be used in an ensemble mode and single-particle mode under dark-field illumination. In the ensemble mode, the sensor is coupled with a microspectrometer and exhibits high specificity, reliability (i.e., linear concentration to signal profile in logarithmic scale), and reusability for repeated endotoxin measurements. Individual endotoxins can be detected by monitoring the color of single AuNPs via a color camera, achieving single-molecule resolution. This platform can potentially advance endotoxin detection to safeguard medical, food, and pharmaceutical products.
Original languageEnglish
Article numbereadf5509
Number of pages9
JournalScience advances
Issue number6
Publication statusPublished - 8 Feb 2023


  • AuNPs
  • Endotoxins
  • sing-molecule


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