A colorimetric aptasensor was developed for selective and sensitive detection of Salmonella typhimurium (S. typhimurium) based on the enhancement of bacteria for the peroxidase-like activity of dual aptamers modified bovine serum albumin stabilized-gold nanoclusters (aptamers@BSA-AuNCs). Micro-sized bacteria was found to be able to capture aptamers@BSA-AuNCs and 3,3′,5,5′-tetramethylbenzidine (TMB), thus promoting the proximity of aptamers@BSA-AuNCs to TMB and greatly increasing the local concentrations of the enzyme-mimetic nanoparticles and their substrate. As a result, addition of bacteria promoted the formation of blue products in the catalytic system, which was utilized to achieve bacteria detection by colorimetry. The parameters influencing the colorimetric aptasensor were optimized by an orthogonal test. Under the selected conditions, the aptasensor exhibited a wide linear response to S. typhimurium in the concentration range of 10¹–10⁶ cfu mL⁻¹ with a detection limit as low as 1 cfu mL⁻¹. The feasibility of the aptasensor was verified by successful detection of S. typhimurium in egg samples with recoveries in the range of 92.4%–110%.

开发了一种比色适体传感器，用于选择性和灵敏检测鼠伤寒沙门氏菌（S. typhimurium) 基于增强细菌对双适配体修饰的牛血清白蛋白稳定金纳米簇 (适配体@BSA-AuNCs) 的过氧化物酶样活性。发现微型细菌能够捕获 aptamers@BSA-AuNCs 和 3,3',5,5'-四甲基联苯胺 (TMB)，从而促进 aptamers@BSA-AuNCs 与 TMB 的接近并大大增加局部浓度酶模拟纳米颗粒及其底物的研究。结果，细菌的加入促进了催化体系中蓝色产物的形成，用于通过比色法实现细菌检测。通过正交试验优化了影响比色适体传感器的参数。在选定的条件下，适体传感器对鼠伤寒沙门氏菌表现出广泛的线性响应在 10 ¹ –10 ⁶ cfu mL ^-1的浓度范围内，检测限低至 1 cfu mL ^-1。通过成功检测鸡蛋样品中的鼠伤寒沙门氏菌，验证了适体传感器的可行性，回收率在 92.4%–110% 范围内。