Creating novel medical diagnostics with a design for manufacturing

Paper-Based Optode Devices (PODs) for Selective Quantification of Potassium in Biological Fluids

This paper describes the design, fabrication, and feasibility of paper-based optode devices (PODs) for sensing potassium selectively in biological fluids. PODs operate in exhaustive mode and integrate with a handheld, smartphone-connected optical reader. This integrated measuring system provides significant advantages over traditional optode membranes and other paper-based designs, by obtaining a linear optical response to potassium concentration via a simple, stackable design and by harnessing a smartphone to provide an easy-to-use interface, thus enabling remote monitoring of diseases.

Microphysiological System Design: Simplicity Is Elegance

Design parameters for microphysiological systems (MPS) are driven by the need for new tools to answer questions focusing on human physiology in a robust and reliable manner. Within this perspective, engineering benchmarks and principles are identified to guide the construction of new devices in the MPS field, with emphasis placed on the design principles common to all tissues, as well as those unique to a subset of tissues. Leading organ replica technologies that recapitulate various functions of the brain, heart, intestine, and lung are highlighted as examples that meet the identified benchmarks and standards, with current barriers for large scale production and commercialization discussed. To reach their full potential and achieve widespread use, MPS will have to be recognized officially by government agencies, and toward this end, considerations of MPS as a potential regulatory tool are presented.

Overreliance on Cost Reduction as a Featured Element of Sensor Design

In this Perspective, we examine the role of cost in sensor design, its meaning within the context of converting academic prototypes into commercial products, and the importance of these issues to clear scientific communication. The possible motivations to consider the cost of a technology, sensor, or assay are both numerous and apparent. However, the idea that the cost of reagents and materials at the laboratory scale will directly translate to the purchase price for a user is inaccurate. While calculating the bill of materials is easy, there are many business considerations that make commercial products entirely different from academic prototypes. With these critical aspects of commercialization considered, academics are often not equipped to predict what the final price of an assay, sensor, or instrument will be to the end user. When used without proper context and accuracy, an overreliance on the phrase "low cost" in the absence of a sufficient discussion of cost weakens the meaning of this popular term and precludes practical scientific advancements. To demonstrate how the relationship between a bill of materials and "expected purchase price" breaks down when considering academic innovations, we discuss pregnancy tests as a case study where an academic bill of materials can lead to both overestimations and underestimations of pricing.

Ampli: A Construction Set for Paperfluidic Systems

The design and fabrication of reconfigurable, modular paperfluidics driven by a prefabricated reusable block library, asynchronous modular paperfluidic linear instrument-free (Ampli) block, are reported. The blocks are inspired by the plug-and-play modularity of electronic breadboards that lower prototyping barriers in circuit design. The resulting biochemical breadboard is a paperfluidic construction set that can be functionalized with chemical, biological, and electrical elements. Ampli blocks can form standard paperfluidic devices without any external instrumentation. Furthermore, their modular nature enhances fluidics in ways that fixed devices cannot. The blocks' ability to start, stop, modify, and reverse reaction flows, reagents, and rates in real time is demonstrated. These enhancements allow users to increase colorimetric signals, fine tune reaction times, and counter check multiplexed diagnostics for false positives or negatives. The modular construction demonstrates that field-ready, distributed fabrication of paper analytical systems can be standardized without requiring the "black box" of craft and technique inherent in paper-based systems. Ampli assembly and point-of-care redesign extends the usability of paper analytical systems and invites user-driven prototyping beyond the lab setting demonstrating "Design for Hack" in diagnostics.