The growing spread of pathogens, caused by anthropogenic activities, pushes the interest of the scientific community towards developing biosensors with improved performance for rapid, simple, and on-site pathogen detection. In this study, we present and discuss a label-free gold nanorod (Au NR) array for the rapid detection of Escherichia coli cells in water, resulting in an effective optical transducer, based on the phenomenon of localized surface plasmon resonance (LSPR). Au NRs with different aspect ratios are functionalized with a suitable antibody by an electrostatic-linking method, resulting in two different Au NR-based bioconjugates. We investigate the ability of the two bioconjugates to detect and spectroscopically recognize E. coli cells dispersed in water by specific antigen–antibody interaction. The results allow selecting the Au NR morphology more suited for preparing the Au NR bioactive array on a glass substrate with excellent optical and morphological properties. The antibody-functionalized Au NR array can detect E. coli cells with high sensitivity and a limit of detection of 8.4 CFU mL⁻¹, resulting in an excellent label-free spectroscopic biosensor. In addition, the multicolor thermoplasmonic properties of the Au NR array, triggered by appropriate light sources, are suited to enable on-demand photothermal disinfection, thus providing an extraordinary capacity for the biosensor to be both disinfected and, more importantly, reutilized.

中文翻译：

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无标记和可重复使用的抗体功能化金纳米棒阵列，用于快速检测水分散体中的大肠杆菌细胞

由人为活动引起的病原体日益蔓延，推动了科学界对开发具有改进性能的生物传感器的兴趣，以实现快速、简单和现场病原体检测。在这项研究中，我们提出并讨论了一种基于局部表面等离子体共振 (LSPR) 现象的无标记金纳米棒 (Au NR) 阵列，用于快速检测水中的大肠杆菌细胞，从而产生一种有效的光学传感器。具有不同纵横比的 Au NR 通过静电连接方法用合适的抗体功能化，从而产生两种不同的基于 Au NR 的生物偶联物。我们研究了两种生物偶联物检测和光谱识别大肠杆菌的能力细胞通过特异性抗原-抗体相互作用分散在水中。结果允许选择更适合于在具有优异光学和形态特性的玻璃基板上制备 Au NR 生物活性阵列的 Au NR 形态。抗体功能化的Au NR阵列可以高灵敏度检测大肠杆菌细胞，检测限为8.4 CFU mL ^-1，是一种出色的无标记光谱生物传感器。此外，由适当光源触发的 Au NR 阵列的多色热等离子体特性适用于实现按需光热消毒，从而为生物传感器提供了非凡的消毒能力，更重要的是，可重复利用。