Enzyme chemotaxis on paper-based devices

Microfluidics has served as a technology for the design and development of a myriad of devices owing to their reduced reagent consumption rate and short sampling-to-result time. Chemotaxis is the movement of materials, particularly biological species, in response to the influence of chemical stimulation. Herein, we describe, for the first time, chemotactic behavior on a microfluidic paper-based analytical device (μPAD) to afford a distribution of products not obtainable under other (non-μPAD) experimental conditions using as a model enzyme-substrate system glucose oxidase (GOx) and glucose. μPADs are easily fabricated by patterning hydrophobic materials in hydrophilic paper. They are low cost, compatible with biological samples, and have shown promise as platforms for various applications and in resource-limited settings.