MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases. Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for COVID-19, for example, incorporate a simple type of microfluidic. But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up. Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process.