Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100083, China.
Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR, 72701, USA.
Talanta. 2022 Mar 1;239:123095. doi: 10.1016/j.talanta.2021.123095. Epub 2021 Nov 26.
A lab-on-a-tube biosensor was established to rapidly, sensitively and automatically detect foodborne bacteria through a rotatable Halbach magnet to form and rotate magnetic nanobead (MNB) chains for specific isolation of target bacteria, gold@platinum nanocatalysts (Au@PtNCs) to label target bacteria for efficient amplification of detection signal and Raspberry Pi App to collect and analyze the image of catalysate. First, the glass tube was successively preloaded with the mixture of MNBs, sample and Au@PtNCs, the washing buffer (skim milk) and the substrate (hydrogen peroxide-3,30,5,50-tetramethylbenzidine), and they were separated by air gaps. After the tube was placed on the biosensor, the MNB chains were stably formed and continuously rotated using the Halbach magnet and the mixture was moved back and forth using a programmable peristaltic pump, thus making the formation of MNB-bacteria-Au@PtNCs complexes. After the washing buffer was moved to wash the complexes, the substrate was then moved to resuspend the complexes, resulting in the catalytic reaction that changed the color of the substrate. Finally, the catalysate was moved to the designated area, the image of which was analyzed by the Raspberry Pi App to quantitatively determine the concentration of bacteria in the samples. This biosensor was able to detect Salmonella in spiked chicken samples in 1 h with lower detection limit of 8 CFU/50 μL and a recovery from 88.96% to 99.74%. This biosensor based on a single tube is very promising to automatically detect foodborne bacteria due to its low cost, high integration and simple operation.
一种管中实验室生物传感器通过可旋转的 Halbach 磁铁快速、灵敏和自动地检测食源性病原体，形成并旋转磁性纳米珠 (MNB) 链以特异性分离目标细菌，金@铂纳米催化剂 (Au@PtNCs) 标记目标细菌，以有效放大检测信号，Raspberry Pi App 收集和分析催化剂图像。首先，将玻璃管依次预加载 MNBs、样品和 Au@PtNCs、洗涤缓冲液（脱脂乳）和底物（过氧化氢-3,30,5,50-四甲基联苯胺），并用气隙隔开。将管放置在生物传感器上后，使用 Halbach 磁铁稳定形成并连续旋转 MNB 链，并使用可编程蠕动泵来回移动混合物，从而形成 MNB-细菌-Au@PtNCs 复合物。在移动洗涤缓冲液以洗涤复合物后，然后移动底物以重新悬浮复合物，从而引发改变底物颜色的催化反应。最后，将催化剂移动到指定区域，由 Raspberry Pi App 分析其图像以定量确定样品中细菌的浓度。该生物传感器能够在 1 小时内检测到鸡肉样本中的沙门氏菌，检测限为 8 CFU/50 μL，回收率为 88.96%至 99.74%。由于其低成本、高集成度和简单操作，基于单管的这种生物传感器非常有希望用于自动检测食源性病原体。
