Water-borne pathogens are mostly generated due to poor sanitation, industrial effluents, and sewage sludge, leading to a significant increase in mortality rate. To prevent this, we need a simple, user-friendly, and rapid on-site detection tool of pathogens, i.e., a biosensor. As contaminated water mainly contains (80%) coliform bacteria, of which Escherichia coli is the major species, we have developed a screen-printed paper-based, label-free biosensor for the detection of E. coli in water. A nanoarchitectured graphene oxide (GO), as a fast electron-transfer flatland, was deposited on the screen-printed graphene (G) on a hydrophobic paper, followed by the immobilization of lectin Concanavalin A (ConA) as a biorecognition element for a GGO_ConA-biosensing electrode. The electrochemical characterization of GGO_ConA shows fast electron transfer with a calculated electroactive surface area of 0.16 cm². The biosensor performance was tested in the sludge water and beach water (real sample) as an analyte using the electrochemical impedance spectroscopy (EIS) technique. The charge-transfer resistance (R_ct) of GGO_ConA increases linearly with the bacterial concentration in the range of 10–10⁸ CFU mL^–1 with an estimated limit of detection (LOD) of 10 CFU mL^–1, which indicates the ultrasensitivity of our biosensor, with 100 times more sensitivity than previous studies. Our reported biosensor, being cost-effective, eco-friendly, and ultrasensitive, may serve greatly as a portable monitoring kit for checking water-borne bacterial contamination.

中文翻译：

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用于监测水生细菌污染的超灵敏、低成本纸质氧化石墨烯纳米生物传感器

水源性病原体主要是由于卫生条件差、工业废水和污水污泥而产生，导致死亡率显着增加。为了防止这种情况发生，我们需要一种简单、用户友好且快速的现场病原体检测工具，即生物传感器。由于受污染的水主要含有 (80%) 大肠菌群，其中大肠杆菌是主要种类，我们开发了一种基于丝网印刷的纸质无标签生物传感器，用于检测大肠杆菌在水里。将纳米结构的氧化石墨烯 (GO) 作为快速电子转移平面沉积在疏水纸上的丝网印刷石墨烯 (G) 上，然后固定凝集素伴刀豆球蛋白 A (ConA) 作为 GGO_ConA 的生物识别元件-生物传感电极。GGO_ConA 的电化学表征显示出快速电子转移，计算出的电活性表面积为 0.16 cm ²。使用电化学阻抗谱 (EIS) 技术在作为分析物的污泥水和海滩水（真实样品）中测试生物传感器的性能。GGO_ConA的电荷转移电阻 ( R _ct ) 在 10–10 ⁸ CFU mL ^–1范围内随细菌浓度线性增加估计检测限 (LOD) 为 10 CFU mL ^–1，这表明我们的生物传感器具有超灵敏性，其灵敏度是之前研究的 100 倍。我们报道的生物传感器具有成本效益、环保和超灵敏的特点，可以作为一种便携式监测工具，用于检查水传播的细菌污染。