Huge discoveries can come from the smallest places — from the empty spaces between minerals and microchips, to the intricate bonds between molecules and atoms. Deep within Duke’s halls, there are machines quietly humming away that make studying these tiny details possible.  

Some machines are about the size of a microwave, while others take up an entire room. Each device is a scientific marvel itself, representing a cutting-edge investment by the university into the future of research. 

Check out just a few of the amazing devices at Duke that let us explore our world from very, very up close. 

Capillary Printer

Inking Out the Future of Electronics

Within the sleek crimson-and-black box that is the Hummink NAZCA printer, a performance takes place on a tiny metallic stage. In the spotlight is a slender glass pipette that sweeps and curves with delicate precision, leaving microscopically thin traces of ink on the surface below. It’s a dance choreographed on a submicron scale, and it could help pave the way for the future of modern electronics. 

Aaron Franklin, the Addy Distinguished Professor of Electrical and Computer Engineering and Chemistry at Duke, first discovered the Hummink NAZCA (which he refers to as “the Hummink”) through a research conference, where he was immediately struck by its potential. As someone who develops environmentally friendly printed electronics, Franklin recognized that this machine could help bridge a gap that had long frustrated the field: How to print electronic materials small enough to be competitive with commercial devices while still using sustainable techniques. 

“The goal isn’t to compete with high-performance computing chips,” he explained, “but to get printed devices that approach the size and performance scale of what’s used in displays and flexible electronics.”  

Securing the Hummink took time. The Shared Materials Instrumentation Facility (SMiF), Duke’s open-access facility for advanced materials science equipment, played a key role in arranging an initial lease for the Hummink at the university. This allowed Franklin and other researchers to test the printer’s capabilities and put together a compelling grant to the NIH for the roughly $400,000 purchase. Their efforts paid off: Today, Duke has one of the first and only Hummink printers currently operating in the United States. 

The Hummink stands apart through its use of capillary flow printing. Within the machine’s stage, a glass micropipette filled with ink hovers near a given surface, and natural capillary forces gently draw out the ink to form continuous, ultrathin lines on the surface. The pipette oscillates at a specific frequency that allows for smooth deposition of the ink as the pipette moves along. 

Franklin’s team filled the pipette with semiconducting carbon-based inks and printed on substrates such as Kapton, a type of plastic film used widely in electronics. The results were flexible thin-film transistors with features that were only a few microns long. The gaps between these printed features — an important element for electrical performance — were even smaller, achieving submicron levels: They measured just nanometers across, or about a thousandth the width of a human hair. 

This level of precision is revolutionary in printed electronics. Traditional methods, like aerosol jet printing, are typically limited to around 10 microns in resolution. The Hummink breaks that barrier, enabling Franklin’s team to create thin-film transistors for devices like displays and folding smartphones in a less costly and waste-intensive manner compared to other production processes. 

Looking ahead, Franklin envisions the Hummink enabling new collaborations across fields—from bioscience to materials engineering—where printing minuscule patterns of expensive or delicate reagents could open new avenues of research.  

“It’s critical to invest early in technologies like this,” he said. “If the U.S. doesn’t continue building new capabilities and supporting tools like this, we risk falling behind in the global technology leadership we’ve always had. These machines let us explore what’s possible before it becomes common—and that’s how breakthroughs happen.” 

MicroCT Scanner

Scanning Across Both Space and Time

Geomaterials are materials that originate from the earth — from the rocks and soil beneath our feet to the cement and concrete that make up buildings. But what happens when rain trickles down through soil, or when concrete is put under the load of a thousand tons? 

Laura Dalton, an assistant professor of civil and environmental engineering, studies how geomaterials respond to changing environmental conditions. So, when she joined Duke, one of the first instruments she sought for her new lab was the Tescan UniTOM XL (nicknamed “Tessie” for short): a top-of-the-line X-ray micro-computed tomography (CT) scanner capable of revealing the hidden intricacies of geomaterials and other structures in real-time. 

Dalton purchased Tessie in spring 2023 with her faculty startup funds—a level of institutional support that she describes as a major reason she chose Duke. The instrument, which cost just under $1 million to purchase, weighs several tons and initially had to be temporarily housed in Gross Hall before being moved to Dalton’s lab. 

But for Dalton, the expenses and wait were worth it. “Everything I do comes back to imaging,” she explained, describing how Tessie allows her team to peer more intimately into the processes that shape built and natural environments. 

A microCT scanner works somewhat like a hospital CT scanner, but at much finer scales. It takes thousands of X-ray images of a sample from different angles, then reconstructs a three-dimensional model that reveals the sample’s shape and interior—showing tiny cracks, pores and other structural elements that shed light on how materials respond to environmental forces. 

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Tessie’s highest scanning resolution is just under one micron and it can house samples up to 1 meter long and 100 pounds in weight. This combination lets Dalton study the smallest details in even relatively large samples. 

But what really makes Tessie impressive is its temporal abilities. Unlike most other microCT scanners, Tessie can perform fast dynamic scans. Thanks to its continuously rotating stage, it can capture a complete 3D image of a sample as quickly as every five seconds, compared to the hour-long scans typical of older machines. This allows Dalton to observe how samples respond to changing conditions — including being crushed by external forces — in real time. 

Dalton also collaborates with other researchers such as Leanne Gilbertson, an associate professor of civil and environmental engineering, to investigate how water, nutrients and contaminants travel through soil structures. Tessie’s ability to visualize change over time helps answer critical environmental questions, such as how pollutants move through the ground. 

Only a handful of UniTOM XL scanners exist globally—Dalton estimates just four globally as of last year, with Tessie being the very first installed in the United States and the first in an academic setting. “A scanner that is this fast, down to the resolutions we can do—that is quite unique,” she said. “I have tons of experience using microCT scanners, but this one brings what we can achieve to a whole new level.” 

Cryo TEMs

Painting a Picture With Frozen Frames

Inside one of the tallest rooms in SMiF, a towering machine runs almost 24/7. Standing at around 13 feet, the Thermo Fisher Scientific Krios Cryo Transmission Electron Microscope  — lovingly called “Krios”— is proof that sometimes it takes some of the biggest tools to uncover the smallest secrets in science. 

A traditional microscope works by shining visible light through a sample and using glass lenses to magnify the resulting view. But when researchers need to see objects smaller than the wavelength of light, like viruses or individual proteins, that’s when Transmission Electron Microscopes (TEMs) come in. Instead of light, a TEM uses a beam of electrons, which have much shorter wavelengths and can reveal structures far smaller than any light microscope could. Samples are flash-frozen (hence the “cryo-” part of cryo-TEM), keeping every molecule locked in its natural shape. Beneath the tall hood of the cryo-TEM, a column of electromagnetic lenses focuses the beam of electrons that pass through the frozen sample and magnifies the resulting image for cameras and other detectors to pick up.  

Krios captures thousands of images of a single sample, which can later be reconstructed into a detailed 3D model. This reconstruction step is similar to what the UniTOM XL microCT scanner does, but at an even smaller scale: Krios’ highest resolution is less than 2 angstroms, which is precise enough to visualize individual atoms in a molecule. 

Installed at Duke in 2018, Krios was among the first four cryo-TEMs in the Carolinas. For engineers such as Tony Huang and Piotr Marszalek, who are both professors of mechanical engineering and materials science, it’s an essential tool for studying phenomena like acoustofluidics and biopolymer mechanics. But the power of Krios extends beyond engineering: It’s a resource shared by several schools at Duke.

“Cryo-TEM is an incredibly powerful tool because it doesn’t require large amounts of material,” said Natalia Pakharukova, a postdoc in the Lefkowitz lab at the School of Medicine who studies G-protein-coupled receptors—one of the most common types of protein receptors in biology. “With Krios, we can see how these receptors interact with other molecules at near-atomic detail.” 

The catch is, running a sample through Krios can take 24-48 hours, and the machine is always in high demand. To make sure researchers get the most out of their time and resources, in 2023 Duke onboarded Krios’ smaller sibling, Tundra. 

Although Tundra’s resolution is lower than Krios’ — around 3 angstroms — it can complete scans in just a few hours and allows researchers to visually screen their samples. A lot of factors can influence the quality of a sample, such as contamination, the thickness of the ice or the clumping behavior of the target molecules. With Tundra, researchers can identify the best-prepared samples relatively quickly and inexpensively before taking them to Krios.  

“Having Krios and Tundra at Duke helps us so much,” said Yang Suo, a postdoc in the Lee Lab at the School of Medicine who studies membrane proteins. “Before, we had to ship samples across the country to places like Portland or New York, but now we can just bring them across the street to SMiF. It saves a lot of time and makes our research much easier.” 

Overseeing Krios and Tundra is Nilakshee Bhattacharya, SMIF’s cryo-TEM Engineer and Cryo-Electron Microscopy (cryo-EM) Manager. With more than 15 years of experience as a cryo-EM expert, she cares for the machines like her own children. “Krios is temperamental sometimes, and I scold it when it acts up,” she said with a laugh. “But when those images appear on the screen, and you can see the viruses and ribosomes taking shape—that’s when everything becomes worth it. The invisible suddenly becomes visible.”

Cryo S/TEM

The Next Big Thing in the World of Small

One of the newest additions to Duke’s suite of imaging tools is currently being installed next door to Krios, and it rivals the towering cryo-TEM in size. The JEOL Grand Arm2 Cryo Scanning/Transmission Electron Microscope (Cryo-S/TEM) is about 13 feet tall and 7 feet wide, and represents an exciting new chapter for Duke’s exploration of the microscopic world.  

Like Krios and Tundra, the Grand Arm2 passes a beam of electrons through a flash-frozen sample to create an image. The main difference in the Grand Arm2’s imaging technique lies in the “scanning” part of its name. While a TEM electron beam illuminates an entire sample all at once, a S/TEM electron beam is focused into a probe that’s only about as wide as a single hydrogen atom. The probe scans the sample point by point, moving back and forth like a printer nozzle. This scanning method offers exceptional contrast and analytical precision — achieving resolutions down to nearly 50 picometers, or roughly quadruple Krios’ highest resolution.  

Miaofang Chi, an expert in atomic‑resolution imaging, recently joined Duke as a professor of mechanical engineering and materials science and will be one of the researchers spearheading the use of the Grand Arm2. Chi’s research focuses on how matter transforms at the smallest scales, with an eye toward applications for energy storage, electronics and sustainable technology. The Grand Arm2’s combination of high-resolution, high-speed scanning and cryogenic capabilities make it particularly useful for studying beam-sensitive materials such as battery and fuel cell components.   

Once the Grand Arm2’s installation is complete, Chi envisions it as a shared platform for discoveries across labs. “This instrument will be an empowering tool for our collaborative research with Professor Olivier Delaire on high-performance composite cathodes for lithium and sodium metal batteries,” she said.  

Many of SMiF’s facilities are also open to users outside of Duke, so the Grand Arm2 is expected to catalyze collaborations with local energy and sustainability industries. As one of only five units currently in the United States, Duke’s Grand Arm2 will provide researchers and industry partners alike a unique opportunity to peer into the some of the tiniest inner workings of our world.