Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing 100083, China.
Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China.
Lab Chip. 2024 Aug 20;24(17):4039-4049. doi: 10.1039/d4lc00366g.
Point-of-care testing of pathogens is becoming more and more important for the prevention and control of food poisoning. Herein, a power-free colorimetric biosensor was presented for rapid detection of using a microfluidic SlipChip for fluidic control and Au@PtPd nanocatalysts for signal amplification. All the procedures, including solution mixing, immune reaction, magnetic separation, residual washing, mimicking catalysis and colorimetric detection, were integrated on this SlipChip. First, the mixture of the bacterial sample, immune magnetic nanobeads (IMBs) and immune Au@PtPd nanocatalysts (INCs), washing buffer and HO-TMB chromogenic substrate were preloaded into the sample, washing and catalysis chambers, respectively. After the top layer of this SlipChip was slid to connect the sample chamber with the separation chamber, the mixture was moved back and forth through the asymmetrical split-and-recombine micromixer by using a disposable syringe to form the IMB--INC sandwich conjugates. Then, the conjugates were captured in the separation chamber using a magnetic field, and the top layer was slid to connect the washing chamber with the separation chamber for washing away excessive INCs. Finally, the top layer was slid to connect the catalysis chamber with the separation chamber, and the colorless substrate was catalyzed by the INCs with peroxidase-mimic activity to generate color change, followed by using a smartphone app to collect and analyze the image to determine the bacterial concentration. This all-in-one microfluidic biosensor enabled simple detection of as low as 101.2 CFU mL within 30 min and was featured with low cost, straightforward operation, and compact design.
即时检测在食源性致病菌的防控中发挥着越来越重要的作用。本研究构建了一种无需外部供电的比色生物传感器，用于快速检测。该传感器采用微流控 SlipChip 进行微流控操作，以 Au@PtPd 纳米催化剂进行信号放大。所有操作步骤，包括溶液混合、免疫反应、磁分离、残留洗涤、模拟催化和比色检测，都在这个 SlipChip 上完成。首先，将细菌样品、免疫磁性纳米珠（IMBs）和免疫 Au@PtPd 纳米催化剂（INCs）、洗涤缓冲液和 HO-TMB 显色底物分别预加载到样品、洗涤和催化室中。当上层 SlipChip 滑到与分离室连接时，通过一次性注射器使混合物在不对称分裂-重组微混合器中来回移动，形成 IMB-INC 三明治偶联物。然后，使用磁场将偶联物捕获在分离室中，并将上层 SlipChip 滑到与分离室连接，以洗涤掉多余的 INCs。最后，将上层 SlipChip 滑到与催化室连接，具有过氧化物酶模拟活性的 INCs 将无色底物催化生成颜色变化，然后使用智能手机应用程序收集和分析图像以确定细菌浓度。这种一体化微流控生物传感器可以在 30 分钟内以低至 101.2 CFU/mL 的浓度简单检测到，具有成本低、操作简单和设计紧凑的特点。
