G-quadruplex fluorescent and lateral flow colorimetric aptasensor for the detection of capsaicin in illicit cooking oil

Mingwei Qin, Imran Mahmood Khan, Ning Ding, Shuo Qi, Xiaoze Dong, Yifei He, Yin Zhang, Zhouping Wang

Research output: Journal PublicationArticlepeer-review

Abstract

The safety of cooking oil is a major global concern and capsaicin (CAP) serves as a crucial marker for assessing its quality. To address this issue, we have devised an innovative biosensor using a truncated aptamer, Cap-1–2, as the foundation for a dual-mode aptasensor. The aptasensor employs a combination of Mg2+-dependent DNAzyme (MNAzyme) cleavage and hybridization chain reaction (HCR) to achieve highly sensitive CAP detection. Notably, the fluorescence signal originates from the inherent fluorescence of thioflavin T (ThT) embedded in a G-quadruplex (G4) structure, enabling the detection of CAP in high-throughput oil samples. Additionally, the biosensor employed the MNAzyme to cleave biotinylated DNA (S1-Biotin), which is subsequently ligated to functionalized gold nanoparticles (AuNPs-Poly A-cDNA), generating outstanding colorimetric signals on lateral flow test strips for immediate point-of-care testing (POCT). The linear detection ranges of the established fluorescence and colorimetric aptasensor were 0.15–80 ng mL−1 and 0.2–100 ng mL−1, respectively, and the limits of detection (LOD) were 0.054 ng mL−1 and 0.137 ng mL−1, respectively. These results demonstrate the practicality of the aptasensor for detecting CAP in real-world samples. Moreover, the aptasensor surpasses traditional biosensors in terms of high-throughput, portability, and sensitivity, making it highly promising for rapid detection in the food industry.

Original languageEnglish
Article number137003
JournalSensors and Actuators, B: Chemical
Volume425
DOIs
Publication statusPublished - 15 Feb 2025

Keywords

  • Capsaicin
  • Cooking oil
  • Food safety
  • High-throughput
  • Point-of-care testing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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