An engineering approach yields a highly potent combination of four antinematode drugs at lower dosages than individual drugs.

In paper microfluidics, the development of smart and versatile switches is critical for the regulation of fluid flow across multiple channels. Past approaches in creating switches are limited by long response times, large actuation fluid volumes, and use of external control circuitry. We seek to mitigate these difficulties through the development of a unique actuator device made entirely out of chromatography paper and incorporated with folds. Selective wetting of the fold with an actuation fluid, either at the crest or trough, serves to raise or lower the actuator's tip and thus engage or break the fluidic contact between channels. Here the actuator's response time is dramatically reduced (within two seconds from wetting) and a very small volume of actuation fluid is consumed (four microliters). Using this actuation principle, we implement six switch configurations which can be grouped as single-pole single-throw (normally OFF and normally ON) and single-pole double-throw (with single and double break). By employing six actuators in parallel, an autonomous colorimetric assay is built to detect the presence of three analytes - glucose, protein, and nitrite - in artificial saliva. Finally, this work brings the concept of origami to paper microfluidics where multiple-fold geometries can be exploited for programmable switching of fluidic connections.

We developed an open microfluidic system to dispense and manipulate discrete droplets on planar plastic sheets. Here, a superhydrophobic material is spray-coated on commercially-available plastic sheets followed by the printing of hydrophilic symbols using an inkjet printer. The patterned plastic sheets are taped to a two-axis tilting platform, powered by stepper motors, that provides mechanical agitation for droplet transport. We demonstrate the following droplet operations: transport of droplets of different sizes, parallel transport of multiple droplets, merging and mixing of multiple droplets, dispensing of smaller droplets from a large droplet or a fluid reservoir, and one-directional transport of droplets. As a proof-of-concept, a colorimetric assay is implemented to measure the glucose concentration in sheep serum. Compared to silicon-based digital microfluidic devices, we believe that the presented system is appealing for various biological experiments because of the ease of altering design layouts of hydrophilic symbols, relatively faster turnaround time in printing plastic sheets, larger area to accommodate more tests, and lower operational costs by using off-the-shelf products.