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line-height: 1.3em;">ur kidneys are particularly susceptible to damage from toxins in our bloodstream because they filter our blood.

line-height: 1.3em;">Scientists have used a "kidney on a chip" device to mimic the flow of medication through human kidneys, a technique that may lead to more precise dosing of drugs, including some toxic medicines used in ICU.

Precise dosing in intensive care units (ICU) is critical, as up to two-thirds of patients in the ICU experience serious kidney injury.

Medications contribute to this injury in more than 20 per cent of cases, largely because many intensive care drugs are potentially dangerous to the kidneys.

The new technique offers a more accurate way to test medications, closely replicating the environment inside a human kidney.

It uses a microfluidic chip device to deliver a precise flow of medication across cultured kidney cells.

This is believed to be the first time such a device has been used to study how a medication behaves in the body over time, called its "pharmacokinetic profile," researchers said.

"When you administer a drug, its concentration goes up quickly and it's gradually filtered out as it flows through the kidneys," said Shuichi Takayama, professor at the University of Michigan.

"A kidney on a chip enables us to simulate that filtering process, providing a much more accurate way to study how medications behave in the body," Takayama said.

Takayama said the use of an artificial device provides the opportunity to run test after test in a controlled environment.

"Even the same dose of the same drug can have very different effects on the kidneys and other organs, depending on how it's administered," said Sejoong Kim, an associate professor at Seoul National University Bundang Hospital.

"This device provides a uniform, inexpensive way to capture data that more accurately reflects actual human patients," said Kim, a former University of Michigan researcher.

The team tested their approach by comparing two different dosing regimens for gentamicin, an antibiotic that is commonly used in ICUs.

They used a microfluidic device that sandwiches a thin, permeable polyester membrane and a layer of cultured kidney cells between top and bottom compartments.

They then pumped a gentamicin solution into the top compartment, where it gradually filtered through the cells and the membrane, simulating the flow of medication through a human kidney.

Researchers then measured damage to the kidney cells inside the device. The results of the test could help doctors better optimise dosing regimens for gentamicin in the future.

The study was published in the journal Biofabrication.