Mad for MXenes

A decade after their discovery at Drexel, the two-dimensional materials are pushing engineers and scientists to reimagine the possible.

Dr. Yury Gogotsi

It’s said that big things come in small packages. And for the past decade, MXenes — two-dimensional fusions of carbon and transition metals first developed at Drexel — have been proving that point, driving innovation across multiple fields of science. Now, a new partnership is opening avenues to help MXenes save lives.

The agreement, a licensing deal between Drexel and Nephria Bio, a U.S. subsidiary of South Korean medical device company EOFlow Co., Ltd., will put MXenes to work as a filter in a wearable artificial kidney device that Nephria Bio is developing. The technology could improve the lives of millions of people who spend hours hooked up to immobile dialysis machines each week.

But new discoveries weren’t always so easy to come by in the field of MXenes. Yury Gogotsi, PhD, Distinguished University and Charles T. and Ruth M. Bach Professor of Materials Science and Engineering and director of the A.J. Drexel Nanomaterials Institute (DNI), was among the researchers who first discovered the materials at Drexel in 2011. The discovery was announced not long after the Nobel Prize in Physics had been awarded to a pair of researchers from England who had done groundbreaking research in graphene, a two-dimensional carbon material. Gogotsi recalls that, in the wake of the Nobel Prize, a flood of research followed on graphene, leaving discovery around MXenes in a relative stasis.

“It took four or five years before the community started paying attention and noticed that we had created many different MXenes that showed unique properties,” Gogotsi shares. “From there, research began to grow.”

This latest development, Gogotsi explains, is due to a discovery that MXenes can be used to filter very small particles, specifically urea, from blood.

MXenes can be used to filter very small particles, streamlining the process of dialysis.

Dialysis is traditionally done by passing blood through several membranes to remove toxins,  typically done by a healthy kidney. The toxins are then carried away by a liquid solution called dialysate. Gogotsi and the DNI discovered that MXenes can help streamline the process.

“I’ve been working for a long time developing carbon-based adsorbents for biomedical applications, but one of the problems is that carbon cannot filter urea, which is very small and easily dissolved in liquid,” he says. “Understanding the chemistry of MXenes, we worked on a hunch to try to find out whether they could adsorb urea. When we found out they could, we published a paper, which got noticed by EOFlow.”

Because the ultimate goal of the project — an artificial kidney the size of a cell phone that can be worn on a belt — would work continuously, it could free patients from the need to undergo treatment multiple times per week due to toxins building up when not directly connected to a machine. This could help them lead fuller, more active lifestyles, improving their overall health results.

In addition to partnering with Nephria Bio, Gogotsi and DNI are working with Meera Harhay, MD, an associate professor of Medicine in Drexel’s College of Medicine, to study the possible health benefits. And while the device is some years away still, use of MXenes can still revolutionize dialysis as we know it today.

“Because MXenes are so much more efficient at filtering, a dialysis machine using MXenes would need far less dialysate to carry toxins away,” Gogotsi explains. “This could drastically reduce the size of the machine, perhaps to the point where patients could have one in their home. As with all important developments, this will happen in several steps, first improving the existing technology and then replacing it with something better down the line.”

“It’s always exciting to discover something. However, it doesn’t mean by default that the research community or community in general will embrace your discovery. You need to show that it matters and it’s important.”

Yury Gogotsi

The project has received grants from the Coulter Foundation and from the National Science Foundation to develop the process. A major boost could come if the group is successful in the Kidney Innovation Accelerator competition, organized by the US Department of Health and Human Services and the American Society of Nephrology, to develop the actual artificial kidney.

Elsewhere in the healthcare field, DNI is teaming with researchers at the University of Pennsylvania to explore the use of MXenes in implantable medical electrodes for monitoring and stimulating electrical activity in the body. Gogotsi explains that MXenes offer several benefits over electrodes made with traditional materials.

“MXene electrodes are stronger, more flexible, and suffer from far less signal loss than those made with gold and platinum,” he says. “And because the transitional metals used to create MXenes are more abundant than precious metals, over time, they will become less expensive and more abundant.”

The funding from the National Institute of Health is helping to explore the possibility that technology can be used to create next-generation monitors to measure muscle function and heart health.

MXenes are also inspiring innovation in the fight against cancer. In a collaboration with Fox Chase Cancer Center, DNI is investigating using MXenes in photodynamic therapy.

“We know that MXenes can adsorb red light, and that light can be converted into heat,” Gogotsi explains. “Targeted heat has been known to kill cancer cells, so we had hoped to focus our research around that. Other researchers started picking up the same ideas and publishing papers, so it’s becoming tough to get funding.”

But competition isn’t necessarily a bad thing in the world of science.

“It’s always exciting to discover something,” Gogotsi says. “However, it doesn’t mean by default that the research community or community in general will embrace your discovery. You need to show that it matters and it’s important.”

In the decade since the first MXene was made, they have come to display properties that no other material can match. They conduct electricity like other metals but can be dispersed in water to make a conductive clay. They can be sprayed onto a surface without any binders, resulting in an ultra-thin film that has already been proven to be as effective at providing cellular signal at bandwidth competing with modern phones. They have a variety of optical properties and can come in in any color of the rainbow, making them perfect for wearable devices. The discovery just doesn’t stop.

“There’s so much that MXenes can do,” Gogotsi says. “The’re the best material for protecting electronic devices from electromagnetic noise. They can protect people from potential microwave radiation. And, because of their conductivity, MXenes can be incorporated into devices with batteries that can be charged within milliseconds, not hours.”

The key to continuing to push the envelope is awareness. As the number of engineers and other scientists who work with the materials increases, their potential uses multiply. And Gogotsi believes that MXenes are on the precipice of an explosion of innovation.

“We held the first-ever international conference on MXenes in 2018, and we had about 200 attendees,” he recalls. “The next year, we had about 450 participants. When the pandemic canceled our plans to host the conference in 2020, we had already seen more than 2,000 registered participants from over 750 different organizations across 60 countries. You can really feel the scale of how this research is expanding. And Drexel, the place where it all started, is still a leader in the field.”