A "kidney on a chip" device from University of Michigan researchers mimics the flow of medication through human kidneys and measures its effect on kidney cells. The new technique supports more precise dosing of drugs, including some potentially toxic medicines often delivered in intensive care units.

The University of Michigan method closely replicates the environment inside a human kidney. A microfluidic chip device delivers a precise flow of medication across cultured kidney cells. The microfluidic technology sandwiches a thin, permeable polyester membrane and the layer of cultured kidney cells between top and bottom compartments.

"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, U-M professor of biomedical engineering. "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 the use of an artificial device provides the opportunity to run repeated tests in a controlled environment. Additionally, the researchers can alter flow through the device to simulate varying levels of kidney function.

The University of Michigan team pumped a gentamicin solution into the microfluidic device's top compartment, where the antibiotic gradually filtered through the cells and the membrane, simulating the flow of medication through a human kidney.

The researchers discovered that a once-daily dose of the medication is significantly less harmful than a continuous infusion.

Takayama said the techniques used in the study should apply to a wide variety of other organs and medications, enabling the gathering of detailed information on how medications affect the heart, liver, and other organs.