The one-step fabrication process rapidly produces miniature chemical factors that could be used to detect diseases or analyse substances.
4 January 2024
13:37
Massachusetts Institute of Technology
An example of one of the devices created by the researchers.
MIT researchers have used 3D printing to develop self-heating microfluidic devices, demonstrating a technique which the team says could one day be used to rapidly create cheap, but accurate, tools to detect various diseases.
Microfluidics, miniaturised machines which manipulate fluids and facilitate chemical reactions, can be used to detect disease in small samples of blood or fluids. At-home Covid-19 test kits for example contain a simple type of microfluidic.
According to the team at MIT, many microfluidic applications necessitate specific temperature chemical reactions. These elaborate gadgets are equipped with heating elements crafted from gold or platinum, manufactured through an expensive process.
The group of MIT researchers employed multi-material 3D printing to construct microfluidic devices that self-heat. These devices, with heating elements integrated, were made using a cost-efficient, single-step process. These designed devices can warm fluid to a designated temperature as it courses through the minuscule channels within the machine.
As reported by the team, the technique is adaptable, enabling an engineer to create a microfluidic device that warms fluid to a specific temperature or delivers specified heating contours within a particular device region. They claim that this approach requires approximately $2 worth of materials to create a ready-to-use microfluidic device.
The method, the researchers suggest, could be particularly beneficial for producing self-heating microfluidics for isolated areas in developing nations. These regions may lack access to the pricey laboratory equipment necessary for some diagnostic procedures.
“Clean rooms, particularly those used for creating these devices, are rather costly to construct and maintain. Nonetheless, we can fabricate equally effective self-heating microfluidic devices using additive manufacturing, much quicker and cheaper than the conventional methods offer. This, indeed, is a step towards democratization of this technology,” opined Luis Fernando Velásquez-García, a top scientist at MIT’s Microsystems Technology Laboratories (MTL) and the senior author of a paper that details this novel technique.
In a conversation with TCT in April 2023, Velásquez-García discussed an MIT venture wherein researchers fabricated wholly 3D printed sensors for satellites. Assisting him on the paper for this innovative process is the lead author, Jorge Cañada Pérez-Sala, a student pursuing graduate studies in electrical engineering and computer science.
This innovative method involves multi-material extrusion 3D printing, a technique where various materials can be expelled via the printer’s nozzles to construct a device. The monolithic nature of the process implies that the device can be manufactured entirely in one step on the 3D printer, eliminating any need for additional assembly post production.
The scientists used two materials to build the devices – polylactic acid (PLA) and an attentively modified version of PLA. The latter is essentially a concoction of PLA and copper nanoparticles, which convert the substance into an electric conductor when mixed into the polymer.
Velásquez-García made an intriguing statement about the behavior of PLA material, explaining, “It’s astonishing to consider. While PLA is normally dielectric, the introduction of these nanoparticle impurities utterly transforms its physical characteristics. This is a phenomenon we haven’t fully comprehended, but it is consistent and repeatable.”
Using this single-step fabrication method, the researchers managed to develop a prototype capable of heating the liquid by 4 degrees Celsius while moving from the inlet to the outlet. This could allow the scientists to build devices that heat fluids in specific patterns or along defined gradients.
Velásquez-García further expressed, “These two materials provide us with the ability to construct chemical reactors tailored to specific needs. We have the ability to establish a specific heating profile while retaining all the functions of the microfluidic system.”
However, they acknowledged a constraint associated with this technique: PLA starts to deteriorate at roughly 50 degrees Celsius. According to the team, many chemical reactions, like those involved in polymerase chain reaction (PCR) tests, need temperatures of 90 degrees or above. To regulate the device’s temperature precisely, the researchers believe that integrating a third, temperature-sensitive material is necessary.
As well as managing these constraints in future projects, Velásquez-García expresses his desire to incorporate magnets directly into the microfluidic device. The group suggests that these magnets could facilitate chemical reactions that necessitate the sorting or alignment of particles.
4 January 2024
13:37
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