“Drop-slip” bulk sample flow on fully inkjet-printed microfluidic paper-based analytical device

• Published in: Sensors and actuators. B, Chemical Vol. 244; pp. 1129 - 1137
• Main Authors: Henares, Terence G., Yamada, Kentaro, Takaki, Shunsuke, Suzuki, Koji, Citterio, Daniel
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.06.2017; Elsevier Science Ltd
• Subjects: Analytical chemistry; Assaying; Colorimetry; Computational fluid dynamics; Copper; Fluids; Free surface flow; Hydrophilic surfaces; Inkjet printing; Liquid flow; Microfluidic paper-based analytical device; Sensors; Slip flow; Surface tension; Transport; Microfluidic paper-based analytical device; Free surface flow; Inkjet printing
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.01.088

[Display omitted] •Sample liquid transport by free surface flow on a paper device is demonstrated.•Channel width and surface tension of sample liquid are dominant factors.•Charged polymeric nanoparticles can immobilize water soluble colorimetric dyes.•No inter-assay cross-contamination by reagent diffusion for at least 60min.•Paper-based analytical devices are entirely fabricated by inkjet printing. With “drop-slip” (DS) bulk liquid flow on a fully inkjet-printed microfluidic paper-based analytical device (μPAD), a new method for the rapid transport of sample liquid is presented. The main driving force for DS flow is the slip flow of fluid on wetted porous cellulose acting as a lubricated surface, which is predominantly influenced by the width of the hydrophilic channel and the surface tension of the sample liquid. The application of DS flow is demonstrated by a model colorimetric metal assay (Zn2+, Cu2+, Fe2+) with inkjet-deposited indicators on a μPAD with optimized channel dimensions of 2mm width and 110μm height. The presence of bulk liquid on the entire device does not result in any mixing of assay components across adjacent sensing regions connected by microfluidic channels. DS flow is a useful alternative sample liquid transport method for μPADs, allowing to perform multiple fully independent assays with enlarged sample volumes without requiring any significant variation in device design and fabrication.