Herein, we developed a sensitive sensing platform for tetracycline detection by combining the specific DNA aptamers with a novel TiO₂ nanocomposite. In this composite, cylinder-shaped TiO₂ nanorods were synthesized on MoS₂ nanospheres by a facile hydrothermal method to produce a MoS₂-TiO₂ composite, which was then aminated. Following that, gold nanoparticles (Au) were deposited on the aminated MoS₂-TiO₂ to form MoS₂-TiO₂@Au composite, on which thiolated DNA aptamers were applied to construct an electrochemical aptasensor. The tetracycline aptamer could well hybridize to its complementary biotin-DNA oligonucleotide (bio-cDNA), and then avidin-horseradish peroxidase (avidin-HRP) mediated by H₂O₂ was introduced to produce amplified electrochemical response. The competition between tetracycline and bio-cDNA for binding of the aptamer would decrease the electrochemical signal, which was used for quantitative detection of tetracycline. The prepared aptasensor showed a wide linear range from 1.5 × 10⁻¹⁰ to 6.0 × 10⁻⁶ M, and a low detection limit of 5 × 10⁻¹¹ M.

在这里，我们通过结合特定的DNA适体与新型TiO ₂纳米复合材料，开发了一种用于四环素检测的灵敏传感平台。在该复合材料中，通过简便的水热法在MoS ₂纳米球上合成了圆柱状的TiO ₂纳米棒，生成了MoS ₂ -TiO ₂复合材料，然后进行了胺化处理。之后，将金纳米颗粒（Au）沉积在胺化的MoS ₂ -TiO _2上以形成MoS ₂ -TiO ₂@Au复合材料，在其上应用了硫醇化的DNA适体来构建电化学适体传感器。四环素适体可以与其互补的生物素-DNA寡核苷酸（bio-cDNA）充分杂交，然后引入由H ₂ O ₂介导的亲和素-辣根过氧化物酶（亲和素-HRP）以产生放大的电化学反应。四环素和生物cDNA之间竞争适体的结合会降低电化学信号，该信号用于定量检测四环素。制备的适体传感器显示出从1.5×10 ^-10到6.0×10 ^-6  M的宽线性范围，和低检测限5×10 ^-11M  。