Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education & Key Disciplines Laboratory of Novel Micro-Nano Devices and System Technology, College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, China; International R & D Center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing, 400044, China.
Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China.
Talanta. 2024 Aug 1;275:126155. doi: 10.1016/j.talanta.2024.126155. Epub 2024 Apr 26.
Developing portable and sensitive biosensors for bacteria detection is highly demanded due to their association with environmental and food safety. Paper-based microfluidic chip is the suitable candidate for constructing pump-free biosensor since paper is hydrophilic, low-cost and easy to use. However, the contradiction between sensitivity and small sample volume seriously affects the application of paper-based chip for bacteria detection. Here, a new microfluidic biosensor, combining large PDMS reservoir for sample storage, hydrophilic paper substrate for pump-free water transport, coated microspheres for bacteria capture and super absorbent resin for water absorption, is designed for the detection of bacteria in aqueous samples. Once the sample solution is introduced in the reservoir, water will automatically flow through the gaps between microspheres and the target bacteria will be captured by the aptamer coated on the surface. To facilitate PDMS reservoir bonding and ensure water transport, the upper side of paper substrate is coated with Polyethylenimine modified PDMS and the bottom side is kept unchanged. After all the solution is filtrated, fluorescent dye strained bacteria are enriched on the microspheres. The fluorescent intensity representing the number of bacteria captured is then measured using a portable instrument. Through the designed microfluidic biosensor, the bacteria detection can be achieved with 2 mL sample solution in less than 15 min for water or 20 min for diluted milk. A linear range from 10 CFU/mL to 1000 CFU/mL is obtained. The paper-based 3D biosensor has the merits of low-cost, simple operation, pump-free and high sensitivity and it can be applied to the simultaneous detection of multiple bacteria via integrating different aptamers.
由于与环境和食品安全有关，因此人们非常需要开发用于细菌检测的便携式和灵敏的生物传感器。基于纸的微流控芯片是构建无泵生物传感器的合适候选者，因为纸具有亲水性、低成本和易于使用的特点。然而，灵敏度和小样本体积之间的矛盾严重影响了基于纸的芯片在细菌检测中的应用。在这里，设计了一种新的微流控生物传感器，它结合了用于储存样本的大 PDMS 储液器、用于无泵水输送的亲水纸基底、用于捕获细菌的涂覆微球以及用于吸水的高吸水性树脂，用于检测水样中的细菌。一旦将样品溶液引入储液器中，水将自动流过微球之间的间隙，并且目标细菌将被涂覆在表面上的适体捕获。为了便于 PDMS 储液器的键合并确保水的输送，纸基底的上侧涂有聚乙二胺改性 PDMS，而底侧保持不变。所有溶液都经过过滤后，荧光染料标记的细菌被富集在微球上。然后使用便携式仪器测量代表捕获的细菌数量的荧光强度。通过设计的微流控生物传感器，可以使用 2 mL 样品溶液在不到 15 分钟的时间内（对于水）或 20 分钟（对于稀释的牛奶）完成细菌检测。获得了从 10 CFU/mL 到 1000 CFU/mL 的线性范围。基于纸的 3D 生物传感器具有成本低、操作简单、无泵和高灵敏度的优点，并且可以通过整合不同的适体来应用于多种细菌的同时检测。
