We demonstrate that polysiloxanes can be tuned to be partially hydrophilic for manipulating the fluidic flow in the pores of cotton thread-based microfluidic devices. A mixture of methanol and isopropanol was used as a diluent for siloxane precursor, which was included into the thread to enable rapid curing of polysiloxanes for fluidic control and enhance detection sensitivity. Interestingly, twelve-fold diluted polysiloxanes enabled desirable fluidic delay and optimum interaction between the targeted antigen and detection antibody-gold nanoparticles (dAb-AuNPs) in the thread-based immunoassay, generating more antigen-dAb-AuNP complexes that bound to the capture antibody (cAb) at the test zone and achieved signal enhancement (∼10-fold over unmodified device). The phenomenon of fluidic delay was evaluated by mathematical simulation, through which the fluidic movement on the polysiloxanes-coated region was observed and the simulation data was in agreement with the experimental data. This polysiloxanes-modified device could detect Salmonella enterica serotype Enteritidis (as a model analyte) in phosphate buffered saline, spiked whole milk, juice and lettuce with the detection limit of 500, 1000, 1000 and 5000 CFU/mL, respectively, which was comparable to or even more sensitive than the existing immunoassays. This work expands the application of polysiloxanes in the microfluidic devices for biomedical diagnosis, water quality monitoring, and food safety surveillance.

我们证明聚硅氧烷可以被调整为部分亲水的，以操纵基于棉线的微流体装置的孔中的流体流动。甲醇和异丙醇的混合物用作硅氧烷前体的稀释剂，该混合物被包括在螺纹中，以能够快速固化聚硅氧烷以进行流体控制并提高检测灵敏度。有趣的是，十二倍稀释的聚硅氧烷能够在基于线程的免疫测定中实现理想的流体延迟和目标抗原与检测抗体-金纳米颗粒（dAb-AuNPs）之间的最佳相互作用，从而产生更多与捕获抗体结合的抗原-dAb-AuNP复合物（cAb）在测试区域并实现了信号增强（比未经修改的器件高约10倍）。通过数学模拟评估了流体延迟现象，通过该过程观察到在聚硅氧烷涂覆区域上的流体运动，并且模拟数据与实验数据一致。这种聚硅氧烷改性的装置可以检测磷酸盐缓冲液，加标全脂牛奶，果汁和生菜中的肠炎沙门氏菌血清型肠炎沙门氏菌（作为模型分析物），其检出限分别为500、1000、1000和5000 CFU / mL。现有的免疫测定。这项工作扩大了聚硅氧烷在生物医学诊断，水质监测和食品安全监测中的微流体装置中的应用。