Researchers develop remarkable dust-sized microgrippers to collect tissue samples autonomously during a biopsy

Microgrippers up close

When a doctor requires a tissue sample to help provide a more detailed medical diagnosis, they have to use traditional tools like forceps and a scalpel. This process is referred to as a biopsy in the medical field, of which there are several different types.

Thanks to developments in recent technology, it looks like doctors may be able to soon rely on “mu-grippers” or tiny electronic devices designed to collect tissue samples (mu stands for micro in Greek). The devices are so small that internal impact would be minimal, and a unique heat activated technology allows them to remain free of batteries, wires or tethers. They’re essentially metal discs, about 300 micrometers in size (making them a little too big to be dubbed as nanotechnology), and they serve one very specific purpose. Thanks to unique metal arms, coated in heat-sensitive polymer, the microgrippers are able to collect tiny bits of tissue which can then be used to provide a diagnosis quickly and more efficiently.

The microgrippers are made entirely of nickel, but the unique polymer coating permits them to contract and expand under various conditions, ultimately allowing the devices to close tightly on bits of tissue. Because of their metal composition they’re obviously magnetic which makes them a lot easier to extract once the job is finished.

Unfortunately, that’s one of the current problems with the microgrippers. After releasing a swarm of them into a source, they can be retrieved with a magnetic catheter but some of the units may actually end up being left behind. It can be compared to dropping sharp objects on a carpet or rug, even with the right tools cleanup can still be quite difficult.

Dr. Gracias from John Hopkins University developed the tiny microgrippers, and his team has also tested the remarkable devices several times. During one of the tests, his team used a pig’s colon as a model because of how similar it is to a human colon.

Another member of the research team, Florin M. Selaru talked about how the project still has further to go until the devices can be used on humans.

“The next step is improving how we deploy the grippers. The concept is sound, but we still need to address some of the details. The other thing we need to do is thorough safety studies.”

The team is currently seeking help from Biotechnology investors and as such they’ve applied for grants to help fund the continuation of the research project. It seems we’re still a few years away from seeing technology used like this in the wild, but it’s still remarkable, nonetheless.

Oh, and in case you’re wondering, the microgrippers have been compared to “dust,” that should provide a more reasonable example of their size.

[via John Hopkins University, Gizmag]

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  • Briley Kenney

    [@kc4cop] Were you speaking directly to Ashraf or me?

    Like [@Coyote] mentioned, when the grippers close down on tissue they collect very small samples. This tissue is what doctors can use to diagnose a patient.

    The devices work autonomously, and like you said it seems possible for them to remain unorganized when collecting samples. How they actually work once inside a body, I’m afraid there’s no mention.

    As for the arms leaving fragments of the infected tissue behind, that definitely seems like a valid concern. The researchers just mentioned that “safety” in general is one of the next hurdles to tackle. So it’s possible they may be aware of something like that- at least I would certainly hope so.

    I’ll admit I have no investment in the medical field nor do I have extensive knowledge. I do my research when writing, but to me this was purely from a technology standpoint. Thanks for outlining those points, it’s always good to hear someone more experienced comment on the matter. :)

  • Coyote

    [@kc4cop] I myself have no medical training but some of this sounds a lot like the “juicers” that were a nano-medical surgery/assisination tool in the old RPG Shadowrun.

    In this case it sounds like the rippers err grippers are sent to a general area where they close their arms collecting from the tissue. By using magnets they could possibly direct the little guys all over the body which isn’t mentioned in this article but is also a new tech being tested. As for how they were used in Shadowrun… much the same.. actually retrieval was not a problem…

  • Ashraf:

    I have practiced medicine for 27 years. I have included biopsing lesions as one of the many diagnostic techniques that I use to help identify a tissue sample. A microscopic dot of tissue selected as supposedly being representative of an entire lesion could be misleading in many of the cases where a biopsy is indicated. Often times we biopsy (example: “excisional biopsy”) a suspected pathological area of tissue looking for the border of the lesion in our biopsy. Depending on the indication for performing a biopsy we might include removal and histological examination of lymph node groups along with the excisional biopsy (surgically removing what appears to be the entire lesion). This would be important in instances such as a malignancy where we want to know “did we get it all”.

    “Shotgun biopsies” where bits and pieces of noncontiguous tissue samples are obtained for study would be a poor way of examining a non-organized lesion. Conclusions would likely be non-diagnostic. One sample may look nothing like other samples, evaluation of the borders of the lesion (if they exist) would be meaningless, and so on.

    How does this biopsy machine described in the above article remove tissue? If protocol requires that one remove the small biopsy machines with a magnet plus if one takes into account the description of the device’s “arms” then one could surmise that the device obtains its tissue sample by ripping small portions of tissue from an intact lesion. Such action would distort the biopsied tissue and make histological examination meaningless.

    Leaving a number of microscopic biopsy entities behind could be a problem – or not. In most cases the biopsy entities would eventually be rejected by the body’s tissue (“spit out”) because the immune system would treat the man-made device as a “foreign body”. Even minimal foreign body rejection or an allergic reaction would lead to pruritus (itching) and the development of a secondary pathological process.

    The above is but a small representation of the facts behind me rejecting this device as becoming a useful diagnostic tool.

    Would I invest any of my money on this research? Nope. I expect that others in the medical community would agree with my interpretation that this device is nothing more than a gimmick. If ever used, I would expect this device to be associated with close to 100% dissatisfaction by patient and clinician alike.