Written by Mike Krapfl and Rachel Cramer | Illustrations by John Jay Cabuay
Researcher Balaji Narasimhan says nanoparticles provide big advantages.
Nanovaccines can be room-temperature stable for up to three years. They can be delivered by a puff from a nasal device. And they’re just the right size to deliver drugs and vaccine components to immune cells in the lungs.
All that is “game-changing,” says Narasimhan, an Anson Marston Distinguished Professor in Engineering and the Vlasta Klima Balloun Faculty Chair who directs the Nanovaccine Institute based at Iowa State University.
“The most important thing I learned from my mentors was to work on problems that matter to people,” he says.
And these days, many of those people problems have nanosized solutions.
The Nanovaccine Institute’s 82 researchers from 27 institutions have teamed up to attract $30-plus million in support and are finding new ways to prevent disease. In many projects they’re formulating nanoparticles with proteins that can train our immune systems to attack pathogens, even cancers.
They rely on those tiny, tiny particles because they efficiently, effectively do the job.
“We shouldn’t do nano for the sake of nano,” Narasimhan says. “We do it because it confers a certain advantage that other scales cannot.”
Jonathan Claussen turns up the enthusiasm standing near a laser engraver that creates all kinds of biosensors in Carmen Gomes’ Nanoscale Biological Engineering Lab on the third floor of Sukup Hall. He’s explaining the idea behind a line on his research group’s website: “WE ARE NANOENGINEERS.” (That’s declarative capitalization by Claussen.)
“I say that because this is really a multi-discipline field. You need an understanding of materials, chemistry, biology, and manufacturing,” he says.
Learn all that, and the website says lab alumni will be ready for, “working in the cutting edge of the world’s innovation economy in industry, national laboratories, and academia.”
“This is a new field, and we’re trying to show that our students have this diverse background they wouldn’t get from a more traditional lab,” says Claussen, an associate professor of mechanical engineering.
Claussen and Gomes, also an associate professor of mechanical engineering, have collaborated for years on the invention and development of printed and laser-treated electrodes for biosensors that take advantage of the unique properties of graphene nanostructures.
Graphene is a wonder material. It’s a carbon honeycomb just one atom thick that’s known for its strength, electrical conductivity, flexibility, and biocompatibility.
Claussen and Gomes have been studying how graphene can be printed or laser-treated to create and tune sensors for everything from detecting COVID to ensuring food safety to measuring plant nutrients.
Claussen demonstrated that last job during a tour of his Nanomaterials and Applications Lab, also on the third floor of Sukup Hall, just a few doors from the Gomes research group.
He slid a beaker from a corner of a countertop and peeled away a plastic sheet covering what looked like liquid grime. Inside, gold metal chips about an inch long held a neat row of four little black sensors that tracked typical plant nutrients such as potassium and nitrate.
The sensors could help hydroponic farmers add just the right amount of fertilizer, boosting production while reducing costs. Claussen says the sensors could be modified for use as soil sensors to monitor nutrients for conventional crops.
Claussen and Gomes have made enough progress in their sensor work – and published enough papers in journals such as Nanoscale Horizons and American Chemical Society Nano – to establish a startup company, NanoSpy, Inc. The company is developing biosensors to quickly detect pathogens in food. As the company declares on its website: “Collection- to-detection in 20 minutes!”
The company just completed phase one of a federal Small Business Innovation Research grant to study the feasibility and commercial potential of sensors that detect Salmonella bacteria and other food contaminants.
“It took a lot of validation to accomplish that,” Gomes says. “We tested different graphene surfaces. We tested reproducibility. We tested that signal response was the same. We tested food safety compliance.”
And now the company is ramping up for a phase two application that would lead to even more testing and development, which could lead to new ideas and inventions.
One idea from the labs is flexible, wearable biomedical sensors that do a quick analysis of your sweat, Gomes and Claussen explained. So, one day the nanoengineers of Iowa State may help you put real-time numbers on your hydration and fatigue levels.
During a recent walk-around tour of his one-of-a-kind nanoscope, Jigang Wang observed that his research group has recently crossed a line.
Wang says in previous visits dating back to 2016 and the early days of building that new sort of microscope, the group could only report some very basic discoveries about electricity traveling without resistance through materials. The early work was all about understanding how fast, powerful flashes of light could control those supercurrents and access exotic states of matter.
Now, with more than $1 million in support from the W.M. Keck Foundation of Los Angeles (www.WMkeck.org), Wang’s lab has a fully functioning Cryogenic Magneto-Terahertz Scanning Near-field Optical Microscope. That’s cm-SNOM for short. And the instrument is as fancy as its name.
There are computerized control systems. A laser source. A maze of mirrors that make an optical path for light pulsing at trillions of cycles per second. A superconducting magnet that surrounds the sample space. A custom-made atomic force microscope. A bright and shiny yellow cryostat that lowers sample temperatures to the kind of cold that turns helium to liquid – about -450 Fahrenheit.
“No one has it. It’s the first in the world,” says Wang, a professor of physics and astronomy who’s also affiliated with the U.S. Department of Energy’s Ames National Laboratory.
The instrument is designed to work in extreme scales of space, time, and energy – billionths of a meter, quadrillionths of a second, and trillions of light waves per second. It’s housed just northwest of campus in the Ames National Lab’s Sensitive Instrument Facility.
Now that the nanoscope is operating, gathering data, and contributing to experiments, Wang says his research group has crossed the line to applied science, the “Science with Practice” highlighted in the middle of the Iowa State seal.
A recent paper from the lab reported the nanoscope can focus down to 20 nanometers, or about 20 billionths of a meter. That’s small enough to give researchers a read on the superconducting properties of materials at extreme scales. That can help researchers understand, and ultimately develop, the inner workings of quantum computing – the emerging generation of super-fast computers based on the mechanics and energies at the quantum world’s atomic and subatomic scales.
“Superconducting technology is a major focus of quantum computing,” Wang says. “So, we need to understand and characterize superconductivity and how it’s controlled with light.”
To make that kind of contribution, the nanoscope will have to be even more precise. Wang is building partnerships that will help make that happen, including work with the Department of Energy’s Superconducting Quantum Materials and Systems Center. And the companies developing quantum computing are taking note of the nanoscope and its promise to help them see, understand, and control the nanostructures in advanced materials.
No wonder Wang enjoys showing off his new lab and its nanoscope.
“The history of modern scientific research,” wrote Wang and his operations team in a recent research paper, “stands upon cycles of great discoveries enabled by the development of revolutionary new machines.”
When she fires up her computer to report her latest research findings, Rizia Bardhan can look to the right for a fifth-floor view of the campus horse barns. Look left, and there on the bookshelf is a framed photo of the family’s three dogs: Nano, Fermi, and Bubbles.
(Nano, for Bardhan’s science. Fermi, after Enrico Fermi, winner of the 1938 Nobel Prize in Physics and namesake of nanomaterials’ “Fermi” energy level. Bubbles, as named by her two young sons.)
Bardhan is an associate professor of chemical and biological engineering who’s also affiliated with the Nanovaccine Institute based at Iowa State. She studies nanostructures with special properties that can be switched on with light, heat, or other stimuli. Those properties can be useful in bioimaging or in treatments for cancers, neurodegenerative disorders, and other diseases.
Visit Bardhan’s Nanophotonics and Nanomedicine Lab, also on the fifth-floor of the Advanced Teaching and Research Building, and you get a short course on the body’s blood-brain barrier.
Bardhan and a team of researchers recently won a grant from the National Science Foundation to develop nanocarriers – they’re no more than 100 billionths of a meter in diameter – that can transport drugs across the barrier and into the brain for treatment of Alzheimer’s disease, epilepsy, and other disorders.
The body makes that very hard to do. The blood-brain barrier is all about keeping bacteria, toxins, pathogens – all the bad stuff – out of the brain. So how do you get medicines across the barrier and into brain cells?
The idea Bardhan and her collaborators are working on involves developing hybrid, soft/hard nanocarriers small enough to cross the barrier and big enough to be filled with brain medicines. There is a soft, fat-like, liposome interior (which is already a clinically approved drug carrier) surrounded by a hard shell of gold nanoparticles.
“If it’s too soft, it will get stuck in cell membrane,” Bardhan says. “If it’s too hard, some immune cells will uptake the nanoparticle and clear it out of the cell.”
This hybrid way, Bardhan says, “provides a broad range of mechanical properties to achieve high cellular intake.”
Faculty, students, and research scientists work in the neighboring laboratories of the Advanced Teaching and Research Building. The Nanovaccine Institute took over the floor in late 2020 and it didn’t take long for counters, shelves, and workspaces to fill with instruments, supplies, lab notebooks, and people.
The $7 million project was made possible with university and donor support, including major gifts from alumni Jim Balloun (’60 industrial engineering), Mike (’59 chemical engineering) and the late Jean Steffenson, and Bob Lane (’68 chemical engineering).
Bardhan has filled her part of the floor with precision instruments such as a spectrophotometer and Raman microscopes. The team running the instruments and gathering the data include a research scientist, a postdoctoral research associate, and four doctoral students.
Just around the corner, her office swells with dozens of the healthiest plants you’ll ever see, and more dog pictures including 10-year-old Nano, a little Cavalier King Charles Spaniel.
“Good things come in small packages, just like nanoparticles,” she says.
Researchers in the Laboratories for Functional Textiles and Protective Clothing are developing nanofiber sensors that could warn agricultural workers of pesticide exposure. The goal is to create something like a Band-Aid that workers could stick to their clothing. If the nanofiber “Band-Aid” detects high levels of pesticide particles in the air, it would change from blue to red.
“The color change would warn the person that they need to leave the area and get some fresh air,” says Chunhui Xiang, associate professor of apparel, events and hospitality management and lead researcher on the project.
Xiang says nanofibers have several unique advantages over traditional fabrics for a project like this. Along with being lightweight and flexible, nanofibers have significantly more surface area.
“They form something like a paper towel. Traditional paper towels are made of thousands of short staple fibers, while the nanofiber mats are made of one single, very thin and long filament with huge surface area,” Xiang says.
This structural difference matters because the nanofiber mats can absorb more chemicals, making the material highly sensitive to pesticide particles. To create their nanofiber sensors, Xiang says the process is similar to making spaghetti noodles.
“You load ingredients into a machine, which combines them and pushes the dough through a die, and the fibers are mechanically drawn to the needed fineness. With nanotechnology, instead of being mechanically drawn, we use electrostatic forces to whip the fibers into nanosize,” Xiang says.
The whipped fibers are deposited on copper mesh or foil. Once dry, the material resembles white tissue paper. It’s soft but strong, almost like skin. The sheets are exposed to UV radiation which gives the sensing materials their initial blue color.
Xiang says the next stage of the research project will focus on developing prototypes and testing them in real-life conditions. With a background in biodegradable nanomaterials, Xiang says she wants to create something that could be discarded in a field and break down naturally.
The nanofiber sensor project is just one example of researchers in the Laboratories for Functional Textiles and Protective Clothing working to improve the health and safety of workers. Other projects include the development of biological self-decontaminating medical gowns and respirators to protect healthcare professionals against live pathogens.
Another project focuses on improving the safety and function of gloves for firefighters and other first responders. With a recent grant from the Federal Emergency Management Agency (FEMA), the researchers are also exploring how to properly clean gear contaminated at fire scenes by smoke and other chemicals.
The lab pulls in expertise from kinesiology, physiology, physics, chemistry, ergonomics, statistics, and mechanical engineering and applies emerging technologies to material and system design. It’s led by Guowen Song, a professor and the Noma Scott Lloyd Chair in Textiles and Clothing.
“We focus on human-centered design and take an interdisciplinary approach for our next generation PPE system. The nanotechnology, as one of the emerging technologies, will ultimately change the textile material and PPE system, and make it smarter,” Song says.