Department of Medical Biotechnology and Translational Medicine, University of Milan, via F.lli Cervi 93, 20054, Segrate, Milan, Italy.
Microfluidics Cluster UPV/EHU, Analytical Microsystems & Materials for Lab-on-a-Chip (AMMa-LOAC) Group, Analytical Chemistry Department, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940, Leioa, Spain.
Mikrochim Acta. 2021 Mar 28;188(4):143. doi: 10.1007/s00604-021-04804-2.
A microfluidic, label-free optical sensor for water pollutants, which is based on a packed micro-column of microspheres with refractive index similar to that of water, is presented. The perfluoropolyether microspheres are synthetized by membrane emulsification followed by UV irradiation. The microfluidic channel hosting the packed column is transparent when filled with pure water as a consequence of refractive index matching, whereas it scatters light in presence of compounds with lipophilic moieties that spontaneously adsorb on the fluorinated microspheres. The device is characterized by investigating the response to cationic and anionic surfactants. Both the signal growth rate and the recovery rate measured during washing with water depend on the type and concentration of the compounds. The cationic surfactants tested display a larger signal increase, linearly scaling with concentration. A limit of detection of 1 μM is obtained in the current configuration. The water index-matched microspheres enable to access an additional analytical parameter, that is the propagation velocity of the scattering signal along the column. This parameter is also found to scale linearly with concentration, hence providing a complementary analytical tool sensitive to the adhesion kinetics.
提出了一种基于具有与水相似折射率的微球填充微柱的微流控无标记光学水污染物传感器。全氟聚醚微球通过膜乳化法合成，然后进行紫外线照射。当充满纯水时，微流道充满了填充柱，由于折射率匹配，它会散射光，而在具有亲脂性部分的化合物存在下，它会自发吸附在氟化微球上。该装置的特点是研究对阳离子和阴离子表面活性剂的响应。在用水洗涤过程中测量的信号增长率和恢复率都取决于化合物的类型和浓度。测试的阳离子表面活性剂显示出更大的信号增加，与浓度呈线性关系。在当前配置中获得了 1 μM 的检测限。水指数匹配的微球能够获得附加的分析参数，即沿柱传播的散射信号的传播速度。该参数也被发现与浓度呈线性关系，因此提供了一种对粘附动力学敏感的补充分析工具。
