For more than 3 million people around the world, kidney failure is a life-altering diagnosis. While about 17 percent of people in the U.S. with end-stage kidney disease are now getting transplants, the average time spent waiting is 3-5 years. These people spend several hours multiple times each week attached to a dialysis machine that cleans the toxins from their blood.
The atom-thin layers of MXene materials have proven to be an effective filter for urea molecules.
Dialysis can temporarily replace the function of the kidney while patients await a transplant. But it can also impose quite a few limitations on the quality of their life - effectively tethering patients to a dialysis machine and likely a medical facility. It's such an imposing sentence that some people choose to delay or forego the procedure and take their chances while waiting for a kidney transplant.
For more than three decades, biomedical engineers and doctors have been working toward a more portable version of the dialysis machine that would restore some normalcy for dialysis patients. But the big problem standing in the way of reducing its size is the large volume of water required to cleanse blood of a particularly persistent waste product called urea.
So the key to downsizing dialysis is removing urea in some other way. That way might be a thin filter made from a unique type of few-atoms-thin material called a MXene, according to research from an international group of scientists, doctors and engineers, led by Drexel University's Yury Gogotsi, PhD, Distinguished University and Bach professor in Drexel's College of Engineering.
MXene materials are composed of nanometer-thin layers whose chemical composition and spacing can be tailored to make them incredibly selective filters. MXene materials have been put to use in trapping electromagnetic radiation, transmitting radio waves and enhancing the flow of electricity. In the paper ACS Nano, the group explains how they can also be designed to filter urea molecules.
"Similar to clays, MXenes' layered structure can be intercalated and deintercalated with water and organic molecules, such as hydrazine, urea and cationic dyes," they write. "This suggests that the MXene structure could potentially be fine-tuned to absorb urea by optimizing the chemical composition and interlaminar distance of the material." In addition to this physical menagerie, the chemical arrangement of the layers also creates a molecular attraction to the urea particles, according to the researchers.
While there is still a long road of refinement and testing ahead of the technology, the possibility of modifying and integrating MXene materials could remove some of its most daunting obstacles. The next step for the researchers is to figure out which type of MXene is the best for filtering urea and to continue tests that show it is safe to use in medical applications.
"This seemingly small discovery, that some new materials can remove urea from the blood, could actually have quite a significant impact on the quality of lives for people with kidney failure," said Sergey Mikhalovsky, PhD, a co-author from the University of Brighton's School of Pharmacy and Biomolecular Sciences, who is currently co-director of a nanomaterials consulting startup called ANAMAD. "Giving patients an alternative to in-clinic dialysis, and a chance to maintain a more normal routine while waiting for a kidney transplant, will ultimately save lives."