Based on a β-cyclodextrin (β-CD) subject-object competition model, a simple and sensitive electrochemical aptamer sensor for the determination of tetracycline (TET) was fabricated. First, the TET aptamer modified with ferrocene (Fc) as a signal molecule was captured by β-CD loaded onto the gold electrode. Subsequently, TET was added to the detection system, causing a binding event between the target and aptamer with strong affinity during which process the aptamer configuration was changed from the original upright linear state to an agglomeration structure, resulting in its departure from the electrode surface. Consequently, an “off-signal” was turned along with the presence of the target. The results indicated that the TET concentration had a linear response to the signal ranging from 0.01 to 100 nM and the accurate detection limit could reach as low as 0.008 nM (3δ). The fabricated TET biosensor also showed outstanding detection specificity. Moreover, the suitability of the developed method was demonstrated in the determination of TET concentrations in different samples comprising water, milk, and bacteria culture medium, achieving acceptable recoveries for spiked samples ranging from 96.0 to 104.4%. This detection system was simple, economical, time-saving but remarkably sensitive, selective, and efficient, potentially rendering services in food safety screening and medical testing.

基于β-环糊精（β-CD）主体竞争模型，制造了一种简单灵敏的电化学适体传感器，用于测定四环素（TET）。首先，被二茂铁（Fc）修饰为信号分子的TET适体被负载在金电极上的β-CD捕获。随后，将TET添加到检测系统中，从而在靶标与适体之间形成具有强亲和力的结合事件，在此过程中，适体构型从原始的直立线性状态变为团聚结构，导致其脱离电极表面。因此，随着目标的出现，“关闭信号”被关闭。结果表明，TET浓度对信号的线性响应范围为0。01至100 nM，准确的检测限可低至0.008 nM（3δ）。制成的TET生物传感器也显示出出色的检测特异性。此外，在测定包括水，牛奶和细菌培养基的不同样品中TET浓度时，证明了所开发方法的适用性，加标样品的回收率在96.0％至104.4％之间，可以达到可接受的回收率。该检测系统简单，经济，省时，但非常灵敏，选择性和高效，有可能在食品安全筛查和医学检测中提供服务。牛奶和细菌培养基，加标样品的回收率在96.0％至104.4％之间。该检测系统简单，经济，省时，但非常灵敏，选择性和高效，有可能在食品安全筛查和医学检测中提供服务。牛奶和细菌培养基，加标样品的回收率在96.0％至104.4％之间。该检测系统简单，经济，省时，但非常灵敏，选择性和高效，有可能在食品安全筛查和医学检测中提供服务。