Kind Of The Opposite Of A Lightsaber

Lightsabers are an elegant weapon for a more civilized age. Did you ever consider that cutting people’s hands off with a laser sword means automatically cauterized wounds and that lack of blood results in a gentler rating from the Motion Picture Association? Movie guidelines aside, a cauterizing pen is found in some first aid kits, but at their core, they are a power source and a heating filament. Given the state of medical technology, this is due for an upgrade, and folks at Arizona State University are hitting all the marks with a combination of near-infrared lasers, gold particles, and protein matrix from silk.

Cauterizing relies on intense heat, or chemicals, to burn flesh but this process uses less power by aiming the near-IR laser at only the selected areas, and since near-IR can penetrate soft-tissue it goes deep without extra heating. The laser heats the gold, and that activates the silk proteins. Early results are positive but lots of testing remains and it still will not belong in the average first aid kit for a while, lasers and all, but surgery for beloved pets and tolerable humans could have recovery time reduced with this advance.

If this doesn’t sate your need for magical space knight weaponry, we have options aplenty.

Via IEEE Spectrum. Image:

22 thoughts on “Kind Of The Opposite Of A Lightsaber

  1. I usually try to avoid negative comments, however this post comes way below the standards I’m used to on hackaday…
    You give a bare minimum explanation of what cauterization is, and then just say “lasers”.

    Is this a new idea?
    How does it change/improve on current methods?
    Does it open up any new possibilities?
    Could it revolutionise some niche use?
    Where could it be used?
    What technical obstacles might they face in developing the technology?

    Come on, where are the nerdy details & hard specs?

    1. Hey Doug, I wrote this article. I would not call your comment negative since you clearly said what you did not like about this article and that is constructive criticism.
      My approach to writing this article was to provide a teaser of the information contained in the paper with the eye-catching title, “Rapid Soft Tissue Approximation and Repair Using Laser‐Activated Silk Nanosealants.” That paper has all the technical stuff you crave while this article is meant to be a high-level scope. I was not trying to give a blow-by-blow of that paper; that would become a very long article. This article also provides a place for you to talk about the tech specs in detail with other commenters.
      Some of your other questions, “Is this a new idea?” “Does it open up any new possibilities?” are questions I want to answer as I write future articles. I have written less than 150 articles for Hackaday and I will consider your comment as some of the most valuable feedback I have gotten.

    2. Since Brian is so kind, I must follow suite. Who, what, when, where, why and how much, are good questions to generally remember to ask and answer. Sixth-grade101. And I would say we all, do not know some really common word. Cauterization is one. Back when we had TVs, some western showed us this when a fellow was shot in the shoulder with an arrow. The medicine was to break off the fletching and carve a groove into the remainder of the shaft which gets filled with the powder from about 2 cartridges. Once.lit, it is rapidly driven home and pulled through by a cohort. Cauterization. Don’t wear it out.

  2. “cauterizing pen is found in some first aid kits, but at their core, they are a power source and a heating filament. Given the state of medical technology, this is due for an upgrade, ”

    Ever hear of an electrosurgical generator? Not a modern update…weve been using bircher hyfrecators since the 1940s. Traditional Electrosurgicals do quite a bit of secondary thermal damage, BUT nothing compared to the filament pens you mention. Plasma mediated electrosurgical systems are vastly superior in cut quality. But dont take my word…..

    1. I recall the common device uses RF? I have seen them mostly on videos of arthroscopic surgeries in the abdomen. Also in the procedures to remove cysts where they stop small bleeders. They make heat, but not with a hot wire or blade.

    2. I had an electrosurgery cauterization performed on me when I was 3-4 years old, inside of my nasal cavity.
      While far superior to previous ‘hot knife’ or ‘hot iron’ methods in the days of old, the electric method still permanently destroyed my sense of smell.

      That isn’t to say I would have preferred the old wild west method of a railway spike sitting in a camp fire to be jammed up there instead (as comical as that mental image is) but imagine bringing the targeting and focus that even a pretty old DVD rom drive laser is capable of to this area, let alone optical tech we’ll have in another decade when this research bares fruit, and it’s hard to not get excited about what this could bring to the table.

      1. Did you know that doctors already have lasers? not just high end surgical suites….TONS of small clinics have surgical lasers. You can even buy one on ebay.

        Also the plasma mediated electrosurgical Ive mentioned, That technology can be used IN THE PLACE of a laser when doing corneal surgery. Its preferred when available because it does EVEN LESS thermal damage than a laser and is MORE precise.

        This article isnt even discussing anything similar. The innovation here isnt a laser that cauterizes bleeders. Its basically a laser activated band. Its using a laser to heat up gold particles in a biopolymer matrix. causing the matrix (silk) to melt and become more of a sticky glue

        This article would have better off discussing sutures, staples, and dermabond than to mention thermal cautery and imply that it was anywhere close to showing the state of medical cauterization. But its hackaday so you cant expect much. Thats why I dripped the update info.

  3. Mostly off topic but a hack of sorts. I got a small cut while shaving, had no alum block or any other product to stop the bleeding quickly enough (in a hurry to leave for work) but I did have a sewing needle and a lighter handy. Only a light touch of the hot needle was enough to cauterise the skin superficially and stop the bleeding. Yes, it stung a bit and surely there must be reasons why that wasn’t the best idea but desperate times… It did the job very efficiently though.

    It goes without saying I’m not encouraging anybody to do this.

    1. Same here, I expected a sword with an elongated black hole in place of the blade. How the hilt ecapes the gravitational attraction of the blade, however, requires Jedi abilities in suspension of disbelief.:)

  4. Brian also didn’t mention the “gold particles” are engineered nanostructures: gold nanorods. Maybe yesterdays news, but they’re pretty cool. Little itty bitty high-Q resonating antenna structures grown of gold. Man made, tuned to resonate with specific frequencies of light, by surface plasmon resonance. Their absorption rate can be so high that they routinely melt from incident pulsed laser light (which promptly de-tunes them and they don’t absorb any more). With the 800 nm CW laser the authors use, at 2-5 W/cm^2, the heating rate is modest, cooking the silk tissue patch at 60-100C.

    Gold nanorods are the optical equivalent of the microwave susceptor, previously seen here:

    1. I remember similar materials being used with diffuse lighting around the same wavelength a decade or so ago as part of a potential tumor treatment. Essentially, the materials were injected into the bloodstream of a (mouse) patient and allowed to precipitate out into tumors over the course of 10 minutes or so. This worked due to the high degree of serum leakage from the blood vessels in tumors.

      After precipitation occurred, the near-IR light source could be applied, causing localized heating inside the tumors, killing the cancer cells. Since tolerance for high heat is much less likely to develop in cancer than resistance to a specific form of chemotherapy, this was seen as a good supplemental treatment. Apparently, the process has been spun off into a company since then, so we may actually see this as a treatment at some point. (

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