Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States.
Department of Biological Sciences, University of Wisconsin-Milwaukee, WI 53211, United States.
Biosens Bioelectron. 2018 Jul 1;110:16-22. doi: 10.1016/j.bios.2018.03.014. Epub 2018 Mar 9.
Contamination of surface and drinking water due to the presence of Escherichia coli bacteria is a major cause of water-borne disease outbreak. To address unmet challenges for practical pathogen detection in contaminated samples, we report fabrication of thermally reduced graphene oxide-based field-effect transistor (rGO FET) passivated with an ultrathin layer of AlO for real-time detection of E. coli bacteria. The sensor could detect a single E. coli cell within 50 s in a 1 µL sample volume. The ultrathin layer of AlO acted as a barrier between rGO and potential interferents present in the sample. E. coli specific antibodies anchored on gold nanoparticles acted as probes for selective capture of E. coli. The high density of negative charge on the surface of E. coli cells strongly modulates the concentration of majority charge carriers in the rGO monolayer, thereby allowing real-time monitoring of E. coli concentration in a given sample. With a low detection limit of single cell, the FET sensor had a linear range of 1-100 CFU in 1 µL volume of sample (i.e., 10 to 10 CFU/ mL). The biosensor with good selectivity and rapid detection was further successfully demonstrated for E. coli sensing in river water. The rGO-based FET sensor provides a low cost and label-free approach, and can be mass produced for detection of a broad spectrum of pathogens in water or other liquid media.
由于大肠杆菌细菌的存在，地表水和饮用水的污染是水传播疾病爆发的主要原因。为了解决在污染样本中实际病原体检测方面的未满足的挑战，我们报告了基于热还原氧化石墨烯的场效应晶体管 (rGO FET) 的制造，该晶体管用超薄的 AlO 层钝化，用于实时检测大肠杆菌细菌。该传感器可以在 50 s 内检测到 1 µL 样品体积中的单个大肠杆菌细胞。超薄的 AlO 层充当 rGO 和样品中存在的潜在干扰物之间的屏障。固定在金纳米颗粒上的大肠杆菌特异性抗体充当探针，用于选择性捕获大肠杆菌。大肠杆菌细胞表面的高密度负电荷强烈调节 rGO 单层中多数电荷载流子的浓度，从而允许实时监测给定样品中的大肠杆菌浓度。该 FET 传感器具有单细胞的低检测限，在 1 µL 体积的样品中具有 1-100 CFU 的线性范围（即 10 至 10 CFU/mL）。该具有良好选择性和快速检测的生物传感器进一步成功地展示了在河水大肠杆菌检测中的应用。基于 rGO 的 FET 传感器提供了一种低成本和无标记的方法，可以大规模生产，用于检测水中或其他液体介质中的广谱病原体。
