A multifunctional magnetic composite material (MSp@PDA) featuring with helical structure, superparamagnetism, photothermal properties, and fluorescence quenching capability was synthesized through sequential magnetization and in-situ polydopamine coating on the Spirulina surface, then applied for multi-scenario application of pathogens capture, sterilization, and sensitive detection. The pathogens capture and sterilization was investigated by loading bacterial broad-spectrum recognition molecule (MPBA) on MSp@PDA, the capture efficiencies of 91.6 % and 94.2 % were obtained for Escherichia coli and Staphylococcus aureus in 15 minutes, respectively, with complete photothermal sterilization achieved within 4 minutes. The fluorescence real-time detection of E. coli and S. aureus was realized by connecting dual-color fluorescent carbon dots to MSp@PDA through specific aptamers (dCD-apt-MSp@PDA), the corresponding detection limits were 2 and 3 cfu·mL⁻¹, respectively, with linear ranges of 10¹∼10⁷ cfu·mL⁻¹. The spiked recovery rates of target bacteria in actual samples were 97.4∼101.1 % and 98.2∼101.4 % for E. coli and S. aureus, respectively. The constructed capture, sterilization, and fluorescence detection methods demonstrated promising application value for on-site monitoring of food-borne pathogens in complex matrices.

中文翻译：

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一种用于光热灭菌和食源性病原体双色荧光检测的聚多巴胺包覆磁性螺旋可切换复合材料


通过顺序磁化和螺旋藻表面原位聚多巴胺涂层，合成了具有螺旋结构、超顺磁性、光热性能和荧光猝灭能力的多功能磁性复合材料 （MSp@PDA），并应用于病原体捕获、灭菌和灵敏检测的多场景应用。通过在 MSp@PDA 上加载细菌广谱识别分子 （MPBA） 来研究病原体的捕获和灭菌，在 15 分钟内对大肠杆菌和金黄色葡萄球菌的捕获效率分别为 91.6 % 和 94.2%，并在 4 分钟内实现完全光热灭菌。通过特异性适配体 （dCD-apt-MSp@PDA） 将双色荧光碳点连接到 MSp@PDA 实现对大肠杆菌和金黄色葡萄球菌的荧光实时检测，相应的检测限分别为 2 和 3 cfu·mL⁻¹，线性范围为 10¹∼10⁷ cfu·mL⁻¹。大肠杆菌和金黄色葡萄球菌在实际样品中目标细菌的加标回收率分别为 97.4∼101.1 % 和 98.2∼101.4 %。构建的捕获、灭菌和荧光检测方法在复杂基质中食源性病原体的现场监测中显示出良好的应用价值。