Better insight into kidney stones with ‘kidney on a slide’

ENGINEERINGNET.BE – About 12% of people suffer from kidney stones and the condition is becoming more and more common worldwide. Rather, it is a recurring problem in a large percentage of patients. Therefore, it is important to thoroughly understand the chemical processes behind the formation of kidney stones.

“The kidneys are still kind of a black box for us,” researcher Burak Eral said. “We can measure what’s going in and what’s going out, but it’s really hard to see what’s going on inside.”

So the researchers developed a microfluidic platform, called a “kidney on a chip,” to be able to see kidney stone formation on a microscopic scale.

The kidney on a chip actually consists of a narrow duct with two entrances: one with fluid similar to the fluid in the kidney, and the other with oil. After a drop of renal fluid is injected into the duct, a drop of oil is added.

In this way, drops of renal fluid are separated from each other, creating renal microenvironments. The tube and drops are so small that the tiniest crystal formation of a kidney stone can be seen with a microscope.

By modifying the composition of the kidney fluid, researchers were able to determine exactly which factors influence the formation of kidney stones. Changes in the pH value and in the concentration of magnesium ensured that formation was delayed or even prevented.

Researcher Fatma Ibis: “This is the first time that this kind of experiment has been carried out on such a small scale, which makes it possible to observe the first signs of crystal formation. On a larger scale, it is only possible to observe the growth of kidney stones that have already formed. So now we can to see the direct effects of changes in renal fluid.”

The researchers used only the most important components to mimic kidney fluid, in fact kidney fluid is more complex. Eral: “The next step is to use synthetic urine, for example, and make the system more complex.”

Ultimately, the researchers believe it will be possible to use the mechanism with patients’ urine to determine a specific treatment for their condition.

Ibis: “Many factors play a role in the formation of kidney stones, and these factors vary from patient to patient. Personal treatment would be an effective way to help patients with kidney stones.”