Department of Chemical Engineering, Northeastern University , 360 Huntington Avenue, 313 Snell Engineering Center, Boston, Massachusetts 02115, United States.
Achira Labs Private Limited , 66B, 13th Cross Road, 2nd Main Road, J.P Nagar Phase III, Bangalore 560078, Karnataka, India.
Anal Chem. 2017 Apr 18;89(8):4671-4679. doi: 10.1021/acs.analchem.7b00275. Epub 2017 Apr 4.
The integration of flow control elements into low-cost biosensors presents a significant engineering challenge. This Article describes the development and integration of active, chemical valves into lateral flow devices, using a scalable, single-step, weaving-based manufacturing approach. The valve was constructed from an electrically conductive polymer, polypyrrole. The polymer switches between wetting and nonwetting states when it is reduced and oxidized via the application of an electrochemical potential. In this work, yarns were first coated with polypyrrole and integrated into fabric lateral flow sensors. The coated yarns were stimulated in situ via integrated electrodes. Coated textiles were characterized for their response to variations in the applied electrical potential, the duration for which the potential is applied, and the chemical composition of the polymer. Among these tuning parameters, the concentration of iron (iii) chloride utilized to catalyze the synthesis of the polymer, was found to be a significant determinant in the wetting range of the polymer. Complete ON/OFF flow control was achieved at applied potentials of 20 V.cm, within 120 s of stimulation, using 0.1 M iron (iii) chloride, making the valve fairly easy to incorporate into point-of-care format. The practical utility of the valve was demonstrated by performing a Lowry protein assay in the device, wherein fluid flow was deactivated to allow individual reaction steps to go to completion prior to reactivation. Significant improvements in the sensitivity and linear range of the devices are reported in a simple straight-channel, lateral flow device, with the potential to develop more complex channel geometries via the weaving-based approach.
将流量控制元件集成到低成本生物传感器中是一项重大的工程挑战。本文描述了使用可扩展的单步编织制造方法将活性化学阀集成到横向流动装置中的开发和集成。该阀由导电聚合物聚吡咯制成。当通过施加电化学电势将其还原和氧化时，聚合物在润湿和不润湿状态之间切换。在这项工作中，首先将聚吡咯涂覆在纱线上，并将其集成到织物横向流动传感器中。通过集成电极对涂覆的纱线进行原位刺激。对涂覆的纺织品进行了响应变化的特性研究，这些变化包括施加的电势能、施加电势能的持续时间以及聚合物的化学成分。在这些调谐参数中，发现用于催化聚合物合成的三氯化铁（iii）浓度是聚合物润湿范围的重要决定因素。在 20 V.cm 的施加电势下，使用 0.1 M 三氯化铁（iii），在 120 s 内即可实现完全的 ON/OFF 流量控制，这使得该阀非常容易集成到即时护理格式中。通过在设备中进行 Lowry 蛋白质测定来证明该阀的实际用途，其中通过停用流体流动来允许各个反应步骤在重新激活之前完成。在简单的直通道横向流动装置中，报告了灵敏度和线性范围的显著提高，通过基于编织的方法有可能开发更复杂的通道几何形状。
