Simple reagent storage in polyester-paper hybrid microdevices for colorimetric detection

A challenge in developing microfluidic devices for fully portable and automated field analyses is the ability to integrate and store reagents in a stable form while maintaining a low cost for the system. Paper-based field-deployable devices are currently the most extensively explored platforms for field use; however, centrifugal devices offer a means for heightened device automation and portability. The basis for many field devices is chemical sensing via colorimetric reactions. Here, we describe the development of polyester-paper hybrid microfluidic devices using a fabrication method, compounded from the print, cut and laminate (PCL) technique, that allows for simple yet effective dry reagent storage for enhanced use with centrifugal or polymeric-based devices. We utilized various proof-of-principle colorimetric assays for multiple applications, including the analysis of total protein, serum albumin, cocaine, 2,4,6-trinitrotoluene (TNT) and iron content. Localized reagent integration facilitated by paper punches allowed for both reagent stability prior to reaction for storage, color stability post-reaction for image analysis, and was compatible for multi-step analyses. Qualitative and quantitative results were achieved with the broad range of sample applications trialed here, while still maintaining the ability for downstream processing. (C) 2017 Elsevier B.V. All rights reserved.