SAVANNAH SZEMETHY
Microfluidic and SEM Art
THE SCIENCE BEHIND THE ART
THE STEAM MOVEMENT
Incorporating the Arts into STEM
The STEAM Movement is a recent drive to reform STEM education through incorporation of the Arts to in order to foster creativity and encourage diversity in science. By providing students the opportunity to create art, they will be allowed to follow their own unique thinking and analysis. STEAM focuses on the development of critical thinking and innovation, which is sometimes lost in STEM education due to its emphasis on following very specific procedures.
WHY MICROFLUIDICS?
Microfluidic devices are small chips with channels and features at the microscale that are intended to scale down laboratory procedures in order to decrease cost and increase efficiency. Microfluidic devices are particularly useful in the biotech industry and for biochemical engineering research due to their ability to mimic the cellular environment.
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Microfluidic devices are the perfect media to bridge the gap between art and science. Because of their small scales, microfluidic chips have a low Reynolds number, thus creating a very smooth laminar flow, allowing for the production of fluid-based artwork. The high resolution of these devices also allows for crisp, clean linework.
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THE MICROFLUIDIC DESIGN AND CREATION PROCESS
Artistic microfluidic devices are created using the processes of photolithography and replica molding.
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First, an artwork is sketched by hand or in Adobe Photoshop. Next, Adobe Illustrator is used to trace over the design for proper scaling. Illustrator is a vector-based software, so any features can be scaled up or down without distorting the image. The design file is then converted to black-and-white and printed as a high-resolution photomask. The design can be initially sketched in color but then needs to be converted to black-and-white for proper transparency. The Illustrator image is also mirrored before printing to ensure proper orientation on the final device.
The photomask is brought into a clean room, where photolithography is performed. As part of the photolithography process, layers of photoresist are spin-coated and baked onto a silicon wafer. The final layer of photoresist is exposed to UV light, baked, and developed in order to transfer the design to the wafer.
A batch of polydimethylsiloxane (PDMS) is mixed in the proportions specified by the manufacturer (typically 10 elastomer : 1 curing agent) and then degassed for 30 min - 2 hours in order to remove all air bubbles. The length of time in the degas chamber is a function of vacuum strength, so stronger, more-tightly sealed chambers will degas much faster. Next, the vacuumed PDMS mixture is poured onto the silicon wafer and baked around 75 Celsius for about an hour.
Once solidified, the area of the PDMS with the design is cut out, and inlets are drilled at their appropriate locations using a Dremel with a very skinny drill-bit or a biopsy punch. The cut PDMS is then plasma-fused to a glass slide for 2-3 minutes in order to create the microfluidic chip. To strengthen the plasma bond, the completed chip can be baked on the hot plate for an additional 30 min at 65 Celsius.
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The completed device is filled using a liquid handling syringe pump in order to ensure precise control of flow rates. Because of their large feature sizes, artistic microfluidic devices have a greater chance of flooding due to a lower amount of bonded surface area between the PDMS and glass slide. By using a liquid handling pump, however, flow can be directed at low rates of <3 mL/hr to reduce the risk of leakage.
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The colored fluid for filling consists of a mixture of DI water, food gel, and ethanol. The food gel is highly concentrated to maximize color intensity. Ethanol is needed to increase the ease of flow through the hydrophobic PDMS.
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Design Process Schematic
Sketch - Illustrator File - Mask - Wafer - Filled Device
Microfluidic art is temporary.
Compared to other forms of art, microfluidic art is a dynamic, temporary medium. While a photograph can eternally preserve the static image, the lifespan of the filled chip itself only lasts for a few hours while liquid still remains. As the fluid evaporates, remnants of dye are left behind, leaving a faint trace of color.
Microfluidic art is reusable.
Even though the colored image only lasts until the fluid evaporates, microfluidic chips can be reused over and over again. The chips can be cleaned with DI water to remove any previous dye residue. This creates the opportunity to experiment with different colors and gradients to see which best suit the design.
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Pictured below are two color variations of the Gothic Spectres design. While the blue and yellow fill run provided better fill and better color mixing, the overall color scheme of the black and purple run better suits the Gothic theme.
BREATHING NEW LIFE INTO SCANNING ELECTRON MICROGRAPHS
With a splash of color, a greyscale Scanning Electron Micrograph can be transformed and express new meaning.