Paper BI-TuP1
Combining Geometry of Folded Paper with Liquid-Infused Polymer Surfaces to Concentrate and Localize Complex Solutions

Tuesday, October 22, 2019, 6:30 pm, Room Union Station B

Diagnostic devices which can provide information relevant to health and safety on-site without the requirement for a fully-equipped laboratory are of great interest for medical, military, and disaster relief applications. However, most research and development work on such devices focuses on detection rather than the preliminary sample handling and preparation. In this work, we demonstrate how low-cost paper materials coated with liquid-infused polymer surfaces can be fabricated and folded to produce shapes which result in functional sample preparation; namely, the simultaneous localization and concentration of a liquid sample. Surfaces were fabricated by infusing commercially-available silicone-release paper with a compatible polydimethylsiloxane oil to create a liquid overlayer. Adhesion tests with Escherichia coli on these surfaces showed no remaining bacterial cells after exposure to a sliding droplet containing 10⁸ cells/mL, compared to the macro- and micro-scale bacterial residues remaining on the controls. Folding of the paper substrates into several 3D engineered arrays enabled clean separation of dye-containing liquids into discreet, pre-defined localized points, whereas the use of uninfused controls resulted in the retention of dye on the sides. When used with a bacterial solution, the combined features of low bacterial adhesion and liquid separation via geometry resulted in the localization of a solution of E. coli and simultaneous concentration by 23.1 (±6.5) times, compared to only 6.78 (±3.6) times for uninfused controls (P= 0.004). This work demonstrates the potential of paper-based materials with liquid-infused polymer surfaces for the manipulation and handling of complex samples which may help in the future design of on-site diagnostics.