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 Fe₃O₄@hollow-TiO₂/Au nanochains (Fe₃O₄@h-TiO₂/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 Fe₃O₄ 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.

四环素（TC）由于在畜牧业和水产养殖业中的滥用，对食品和环境安全构成了极大的威胁。因此，需要一种有效的分析方法来检测 TC，以防止可能的危害。在此，基于适体、无酶 DNA 电路和 SERS 技术构建了用于灵敏测定 TC 的级联放大 SERS 适体传感器。捕获探针和信号探针是通过将DNA发夹H1和H2结合到制备的Fe ₃ O ₄ @hollow-TiO ₂ /Au纳米链（Fe ₃ O ₄ @h-TiO ₂/Au NCs) 和 Au@4-MBA@Ag 纳米粒子。EDC-CHA 电路的双重放大显着促进了适体传感器的灵敏度。_{此外，Fe 3} O ₄的引入由于其卓越的磁性而简化了传感平台的操作。在最佳条件下，开发的适体传感器对 TC 表现出明显的线性响应，检测下限为 15.91 pg mL ^-1. 此外，所提出的级联扩增传感策略表现出优异的特异性和储存稳定性，其实用性和可靠性通过实际样品的TC检测得到验证。该研究为食品安全领域特异灵敏的信号放大分析平台的开发提供了一个有前途的思路。