Because they filter our blood, our kidneys are particularly susceptible to damage from toxins in our bloodstream. That's why kidney failure can occur when people are given too high a dosage of certain medications. So, how do drug developers know how much is safe? Typically, it's through animal testing, although University of Michigan researchers have now developed something that could be more accurate – a "kidney-on-a-chip."

One of the problems with using lab animals is that they tend to process medication at different rates than humans, leaving developers to extrapolate the results of tests. By contrast, the kidney-on-a-chip is said to much more closely mimic the rate at which human kidneys take up drugs in the bloodstream.

Additionally, while every animal is slightly different, the chip allows for parameters to be strictly regulated over a series of tests.

The glass slide-type device contains live cultured human kidney cells within a permeable polyester membrane, sandwiched between top and bottom compartments. Solutions containing different concentrations of medications are introduced to the top compartment, and are guided by microfluidic channels to flow through the membrane and kidney cells, before reaching the bottom. The cells are then examined under a microscope, to see how they fared.

Besides testing different dosages, it's also possible to try different methods of administering the same dose. In one experiment, for example, the scientists simulated both a high-concentration single shot of a commonly-used antibiotic, along with a lower-concentration drip of the type that would be gradually administered by IV. Although both methods ultimately delivered the same amount of the drug, it was found that less kidney damage occurred when the single-shot method was used.

A paper on the research was recently published in the journal Biofabrication.