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<p> An innovative "turn-on" surface-enhanced Raman scattering (SERS) biosensor for ultrasensitive ochratoxin A (OTA) monitoring by a tetrahedral DNA nanostructure (TDN)&#xa0;is introduced, which provides high mechanical strength and stability. The TDN framework was engineered with an OTA-specific aptamer conjugated at one edge, while two adjacent vertices were functionalized with Ag@4-aminothiophenol (4-ATP) nanoparticles via thiolated linker strands. Upon target recognition, aptamer-OTA binding triggers a programmable conformational switching of the TDN. This switching spatially regulates the electromagnetic field coupling between adjacent Ag@4-ATP hotspots, thereby amplifying the SERS signal in a target-dependent manner. Compared to conventional SERS platforms, this strategy exhibits higher sensitivity, with a linear response over six orders of magnitude (0.39–10000&#xa0;pg/mL, <i>R</i><sup>2</sup> = 0.998) and an ultralow limit of detection (LOD) of 0.117&#xa0;pg/mL. Field validation using spiked peanut and soybean samples showed excellent correlation with high-performance liquid chromatography (HPLC) reference measurements, while reducing the analysis time from &gt; 1&#xa0;h to &lt; 5&#xa0;min per sample. By modifying the tetrahedral DNA sequences, this approach holds promise for the detection of multiple mycotoxins in food enhancing food safety and protecting public health.</p> Graphical abstract <p></p>

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A surface-enhanced Raman scattering sensor based on tetrahedral DNA-Ag@4-ATP nanostructures for ultrasensitive detection of ochratoxin A

  • 期刊论文

  • 发表日期：

    2026年2月26日

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  • Liming Guo,
  • Bo Wang,
  • Jie Zhang,
  • Xiangyu Ma,
  • XiuFang Zhu,
  • Liangdong Feng,
  • Ying Bao,
  • Jiadong Zhang,
  • Yi Chen

摘要

An innovative "turn-on" surface-enhanced Raman scattering (SERS) biosensor for ultrasensitive ochratoxin A (OTA) monitoring by a tetrahedral DNA nanostructure (TDN) is introduced, which provides high mechanical strength and stability. The TDN framework was engineered with an OTA-specific aptamer conjugated at one edge, while two adjacent vertices were functionalized with Ag@4-aminothiophenol (4-ATP) nanoparticles via thiolated linker strands. Upon target recognition, aptamer-OTA binding triggers a programmable conformational switching of the TDN. This switching spatially regulates the electromagnetic field coupling between adjacent Ag@4-ATP hotspots, thereby amplifying the SERS signal in a target-dependent manner. Compared to conventional SERS platforms, this strategy exhibits higher sensitivity, with a linear response over six orders of magnitude (0.39–10000 pg/mL, R2 = 0.998) and an ultralow limit of detection (LOD) of 0.117 pg/mL. Field validation using spiked peanut and soybean samples showed excellent correlation with high-performance liquid chromatography (HPLC) reference measurements, while reducing the analysis time from > 1 h to < 5 min per sample. By modifying the tetrahedral DNA sequences, this approach holds promise for the detection of multiple mycotoxins in food enhancing food safety and protecting public health.

Graphical abstract