Yuan et al. 2023 — Fluorescent aptasensor for As(III) detection using triple-helix molecular switch
This paper from the Shanghai Engineering Research Center of Food Rapid Detection describes a novel fluorescence-based aptasensor for the detection of As(III) ions using a triple-helix molecular switch (THMS) platform. The system uses an arsenic-binding aptamer combined with a dual-labeled signal transduction probe (FAM fluorophore and BHQ1 quencher); in the absence of As(III) the triple helix structure holds the probe open and fluorescence is high, while As(III) binding breaks the triple helix and releases the probe to fold back into a hairpin that quenches fluorescence. The sensor achieves a detection limit of 69.95 nM (approximately 5.2 µg/L) with a linear range of 0.1 to 2.5 µM, and the total detection process takes 30 minutes. Real-sample validation was performed using Huangpu River water with good recoveries, and the authors estimate cost per test below USD 1.
Key numbers
- LOD: 69.95 nM As(III) (~5.2 µg/L)
- Linear range: 0.1 to 2.5 µM As(III)
- Detection time: 30 min
- Real sample: Huangpu River water, acceptable recoveries (specific values not extracted from abstract)
- Cost: <USD 1 per test
Methods (brief)
Fluorescent aptasensor based on triple-helix molecular switch (THMS). Signal transduction probe labeled with FAM (fluorophore) and BHQ1 (quencher). As(III) specifically disrupts the triple helix causing fluorescence quenching. Optimized unwinding temperature 60°C; optimal aptamer arm length 10 bases (Apt-10). No ICP-MS or speciation instrument required.
Implications
Certification: Not directly applicable to HMT&C threshold setting; no food matrix concentration data reported. Courses: Useful for illustrating low-cost, field-deployable arsenic detection alternatives to ICP-MS; relevant to testing method module. App: Not applicable (no food concentration data).