Think of 3-D printing and you probably think of plastic gadgets like this bizarre toothbrush, but the technology can also be used for “bioprinting” things like human stem cells. Using a hacked MakerBot printer, a bioengineering researcher has discovered that 3-D-printed stem cells are physiologically viable when they come out of the machine–which means they could one day be used to replace animal testing of new drugs.
“The inherent problem with animal testing is that you’re trying to get a human response to a drug, but animals, of course, aren’t the same and give you a different response,” says Alan Faulkner-Jones, a PhD student in biomedical microengineering at Heriot-Watt University in Scotland. “The standard approach is that you tweak the drug so that it works better on animals, which unfortunately means that sometimes it works less well on humans and can create side effects.”
The majority of experimental drugs, in fact, don’t make it past the animal testing phase. In the U.S., the FDA reports that nine out of 10 drugs fail when they’re actually tested on humans. And yet animal testing remains a required step in the approval process for most drugs.
That’s where the bioprinter comes in. The technology works in a complex series of steps: Researchers take cells from healthy people, turn them into stem cells, turn the stem cells into organ-specific cells, and then use the printer to pattern them into correct structures in three dimensions. At the end of the process, the researchers end up with a “micro-tissue” that’s smaller than an organ but has the same physiological responses. “We can use these for drug testing, and if we get it right, they will respond the same way they would in the body,” said Faulkner-Jones.
The mini-organs could also be put together in what’s being called a “human on a chip”–a micro-scale version of the human body that can show how the entire system would respond to a particular drug. It could also eventually be used with a specific person’s cells to help test their individual response to a drug.
Faulkner-Jones estimates he and other researchers will be able to create the micro-tissues in five years. Then, after jumping through the necessary regulatory hoops, drug developers could start using the process to make better medicine.
Of course, the technology will also help spare future mice from a life in the lab. “The basic motivating factor for me is that the engineering itself is very interesting and challenging,” Faulkner-Jones said. “But as soon as we worked out that this could be used for–hopefully–bringing an end to animal testing, that was pretty motivating as well.”