Colorimetric detection of pathogenic bacteria in food still faces many challenges. Herein, a novel label-free and ultrasensitive colorimetric aptasensor was firstly established for the detection of food-borne pathogenic like Staphylococcus aureus (S. aureus) based on oligonucleotide-mediated the oxidase-mimicking activity of octahedral Mn₃O₄ nanoparticles (NPs). The study confirmed that the common oligonucleotide such as SA31 aptamer can adsorb on the surface of octahedral Mn₃O₄ NPs, and significantly inhibit the oxidase-mimicking activity by blocking their electron transfer to 3,3′,5,5′-tetramethylbenzidine. In the presence of S. aureus, aptamers will preferentially bind to bacterial cell, resulting in the recovery of oxidase-mimicking activity. The naked eye can easily recognize the color change from green to yellow, with the increase concentration of S. aureus from 10 CFU·mL⁻¹ to 2 × 10⁵ CFU·mL⁻¹. The colorimetric aptasensor shows a low detection limit of 3 CFU·mL⁻¹ (S/N = 3). This strategy has excellent selectivity whether the presence of other competitive bacteria, and has been successfully applied to the non-enrichment detection of S. aureus in milk and pork samples.

食品中致病菌的比色检测仍面临诸多挑战。在此，基于寡核苷酸介导的八面体Mn ₃ O ₄纳米颗粒（NPs）的氧化酶模拟活性，首次建立了一种新型的无标记超灵敏比色适体传感器，用于检测食源性致病菌如金黄色葡萄球菌（S. aureus）。 . 研究证实，常见的寡核苷酸如SA31适体可以吸附在八面体Mn ₃ O ₄ NPs的表面，并通过阻止其电子转移到3,3',5,5'-四甲基联苯胺，显着抑制氧化酶模拟活性。在存在金黄色葡萄球菌的情况下，适体将优先与细菌细胞结合，导致氧化酶模拟活性的恢复。随着金黄色葡萄球菌的浓度从10 CFU·mL ^-1增加到2×10 ⁵ CFU·mL ^-1，肉眼可以很容易地识别出从绿色到黄色的颜色变化。比色适体传感器显示出 3 CFU·mL ^-1 (S/N = 3)的低检测限。无论是否存在其他竞争性细菌，该策略都具有出色的选择性，并已成功应用于牛奶和猪肉样品中金黄色葡萄球菌的非富集检测。