Concatenated dynamic DNA network modulated SERS aptasensor based on gold-magnetic nanochains and Au@Ag nanoparticles for enzyme-free amplification analysis of tetracycline.

Tetracycline (TC) poses a great threat to food and environmental safety due to its misuse in animal husbandry and aquaculture. Therefore, an efficient analytical method is needed for the detection of TC to prevent possible hazards. Herein, a cascade amplification SERS aptasensor for sensitive determination of TC was constructed based on aptamer, enzyme-free DNA circuits, and SERS technology. The capture probe and signal probe were obtained by binding DNA hairpins H1 and H2 to the prepared Fe ₃ O ₄ @hollow-TiO ₂ /Au nanochains (Fe ₃ O ₄ @h-TiO ₂ /Au NCs) and Au@4-MBA@Ag nanoparticles, respectively. The dual amplification of EDC-CHA circuits significantly facilitated the sensitivity of the aptasensor. Additionally, the introduction of Fe ₃ O ₄ simplified the operation of the sensing platform due to its superb magnetic capability. Under optimal conditions, the developed aptasensor exhibited a distinct linear response to TC with a low limit of detection of 15.91 pg mL ^-1 . Furthermore, the proposed cascaded amplification sensing strategy exhibited excellent specificity and storage stability, and its practicability and reliability were verified by TC detection of real samples. This study provides a promising idea for the development of specific and sensitive signal amplification analysis platforms in the field of food safety.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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