New and improved surgical biopsies

When doctors are trying to figure out what’s wrong with you, they’ll often want to take a biopsy of the affected area. This usually means inserting a pair of biopsy forceps and pinching off a piece of your flesh. You can see an example of such a device below, courtesy of Device Technologies. 

If it makes you squeamish, note that the jaws of such tools are only a couple of millimeters long. That’s not tiny enough for the researchers at Johns Hopkins, however, who have manufactured and tested autonomous microgrippers that are ten times smaller.

This image depicts an mu-gripper near the opening of an endoscopic catheter. 
Credit: Evin Gultepe, Gracias Lab, Johns Hopkins University.

The minute star-shaped objects are composed of temperature-sensitive metals that squeeze closed when they are exposed to body temperature. Doctors can use a catheter to deploy hundreds, or even thousands, of them into a suspicious region of the body. In a few minutes, the microgrippers warm up and close around tissue samples. Because the grippers contain nickel, they can then be collected with a magnetic probe.

This is much less invasive than conventional tissue sampling for a number of reasons. First, you’re collecting much smaller samples. Second, you can deploy as many microgrippers as you need to be reasonably sure you’re getting a representative tissue sample. To get the same result, doctors might have to make tens of sequential forceps biopsies. Finally, you need far less precision and training to get the samples you want, which might make it faster and easier to perform biopsies.

So far, animal tests have been promising, though more refinements will be necessary before the doctors move on to human trials. At a minimum, I'm sure patients will want to know whether doctors can reliably retrieve every last microgripper and what the dangers are of leaving one behind.

Here's an animation explaining their usage:

Or watch one in action here:

Gultepe, E., Yamanaka, S., Laflin, K., Kadam, S., Shim, Y., Olaru, A., Limketkai, B., Khashab, M., Kalloo, A., Gracias, D., & Selaru, F. (2013). Biologic Tissue Sampling With Untethered Microgrippers Gastroenterology, 144 (4), 691-693 DOI: 10.1053/j.gastro.2013.01.066.