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Where the two hottest fields of engineering intersect, researchers at Montana State University have literally made a small breakthrough, but this breakthrough could have had a huge impact on a wide range of applications.
Additive manufacturing (AM) has become an increasingly viable option for manufacturing fluid equipment. Reduced polymer printing (VPP) such as stereolithography (SLA) and digital light processing (DLP) is a popular technique for creating 3D printed microfluidics due to its high resolution. 3D printing creates high-throughput fluid devices in one step in computer-aided design (CAD) software and directly adjusts device parameters. Simply share design files and distribute and replicate designs and equipment across different facilities. In this paper, a research team led by Assistant Professor Stephan Warnat from Montana State University in the United States demonstrates the integration of miniature sensors on glass with high-resolution 3D printing technology, a new way to make microfluidic devices using 3D printing technology, including manipulating very small volumes of liquid to measure water quality or study microbes.
Glass substrates are a viable way to create optically transparent channels using high-resolution printing techniques such as VPP or material jetting above, but sensor integration often requires a multi-step integration process. In this study, a glass-based impedance conductivity sensor was integrated directly into a 3D printed flow channel as a proof-of-concept device. The device shows that it can be used as both a conductivity sensor and a bacterial cell detector. This is achieved by printing directly on a glass substrate with patterned electrodes without using the base layer of the DLP resin printer.
Optically transparent surfaces within microfluidic devices are essential for accurate quantification of chemical, biological, and mechanical interactions. However, despite the manufacturing flexibility of 3D printed microfluidic prototypes compared to traditional technologies, 3D printed resins can also create translucent channels due to surface roughness and defects. Although it is theoretically possible to create a transparent device using a transparent resin, inherent surface defects can cause light to diffuse, creating translucent channels.
The image comes from the Internet
Warnat and his team demonstrated using the new method that they could 3D print directly on glass to form a fine channel containing liquid (less than 1 millimeter wide). The new process significantly reduces manufacturing time and enables researchers to easily produce affordable prototypes of custom devices in their labs – microfluidic chips. Warnat says the entire transition from production start to final testing can take up to a day. He estimates that the material cost of using the new method to make a typical chip is about $1.
Images of the micromachined sensors used in this work
Michael Neubauer, a graduate student at Montana State University who co-authored the article with Warna, made metal sensors using a microfabrication facility in Montana that he described as interlocking fingers that could measure changes in current to detect certain minerals in water.
Warnat himself plans to use the new technology to further develop new, cheaper miniature sensors for measuring water quality in rivers and soils. His project is one of three projects that MSU received $50,000 in "seed" funding granted last year through the Consortium for Environmental Water Systems Research (CREWS), which received $20 million from the National Science Foundation earlier in 2019. The Cruise Research Seed Award Program is designed to fund innovative research to build research capacity in Montana's institutions of higher education.
Other MSU researchers at the MSU Biofilm Engineering Center have expressed interest in using this new technique for a variety of research projects involving microbes. Christine Foreman, a professor in the Department of Chemical and Biological Engineering who has been working with the Warnert team, said: "These sensors are low cost and small size, making them ideal for use in environmental and industrial applications that require extensive measurements at multiple locations."
Dan Miller, head of the Mechanical and Industrial Engineering Department, said: "There are indeed many opportunities for applying this technology to research across a wide range of disciplines. Future research is being done in these interdisciplinary teams, and as such, Warnat is in the lead. ”
Stephan Warnat (left) and PhD student Michael Neubauer are working on 3D printed microfluidic chips with embedded sensors in their labs. Image credit: Adrian Sanchez-Gonzalez
Warnat said the collaborative nature of the Biofilm Engineering Center, combined with the capabilities of the Montana micromanufacturing facility, helps inspire and support the development of 3D printing technology. And the response to this achievement has been very encouraging.
The new findings allow sensors to be 3D printed directly on motor organs
Source of this article: DOI: 10.1088/2631-8695/ab5e9f