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  1. source
    View attachment 28184 Painful injections could eventually be a thing of the past, thanks to a breakthough by a team at Seoul National University in South Korea.

    A new laser-based system that blasts microscopic jets of drugs into the skin is set to make jabs as painless as being hit with a puff of air.

    Jack Yoh, professor of mechanical and aerospace engineering at the university, developed the device along with his graduate students.

    The system uses an erbium-doped yttrium aluminum garnet, or Er:YAG, laser to propel a tiny, precise stream of medicine with just the right amount of force.

    This type of laser is commonly used by dermatologists, particularly for facial aesthetic treatments, said Professor Yoh, who described the injector in a paper published in the Optical Society of America's journal Optics Letters.

    The laser is combined with a small adapter that contains the drug to be delivered, in liquid form, plus a chamber containing water that acts as a "driving" fluid.

    A flexible membrane separates these two liquids. Each laser pulse, which lasts just 250 millionths of a second, generates a vapour bubble inside the driving fluid.

    The pressure of that bubble puts elastic strain on the membrane, causing the drug to be forcefully ejected from a miniature nozzle in a narrow jet a mere 150 millionths of a metre (micrometres) in diameter, just a little larger than the width of a human hair.

    Professor Yoh said: "The impacting jet pressure is higher than the skin tensile strength and thus causes the jet to smoothly penetrate into the targeted depth underneath the skin, without any splashback of the drug."

    Tests on Guinea pig skin show that the drug-laden jet can penetrate up to several millimetres beneath the skin surface, with no damage to the tissue.

    Because of the narrowness and quickness of the jet, it should cause little or no pain, Professor Yoh said.

    The team's aim is the epidermal layer, which is located closer to the skin surface, at a depth of only about 500 micrometres.

    This region of the skin has no nerve endings, so the method will be completely pain-free, he insisted.

    Although other research groups have developed similar injectors, they are mechanically driven, using piston-like devices to force drugs into the skin, which gives less control over the jet strength and the drug dosage.

    "The laser-driven microjet injector can precisely control dose and the depth of drug penetration underneath the skin," the Professor added.

    "Control via laser power is the major advancement over other devices."

    Friday 14 September 2012, Sky News

Comments

  1. Gradient
    Here's the initial publication: A laser syringe aimed at delivering drug into the outer layer of human skin

    This is a very interesting innovation, but - in the interest of full disclosure - there are some significant limitations when considered from a recreational perspective.

    To put this in perspective, 100nanoliters is equivalent to 0.0001cc or 0.0001mL - or, 0.01% of 1mL or cc; this is a very, very small volume. Granted, if one was working with a very concentrated solution - you could simply do several administrations to reach your target. They showed that simply doing several injections increased the payload volume, so it'd simply take a little bit of calculating to figure out how much is delivered per injection - but I imagine there's a ceiling. Given that it's ostensibly painless, no biggie there. However, this is further limited by another characteristic of this technology.

    Note how they don't discuss the maximal depth obtained in 7% gelatin, the toughness replicating animal skin; they maxed out at 1.2mm - which is sufficient for intravenous delivery only in certain areas. They're not marketing this as an IV delivery method, but this would be something to consider from a recreational perspective; injectors will have to program this device to proper depths in order to hit the depth of vasculature - and not over/undershoot. All things considered - I'd imagine that this kind of device would be better suited for intramuscular delivery, rather than intravenous.

    However, this somewhat shallow depth shouldn't be an issue given that you're not puncturing epithelial cells - though, the obvious next step for them is to evaluate the effects of this delivery modality on the integrity of vascular epithelial cells. If repeated penetration between epithelial cells disrupts integrin, collagen, etc. function - then this may translate to vascular necrosis, which can become hairy very fast.

    Regardless, this is a very interesting development that'll likely lead to further innovations.
  2. nigh
    I don't see how this could be scaled up without causing significant tissue damage. I can see this as being useful in the future for drugs active at the µg level such as LSD and possibly 25i-NBOMe, but not anything else. Botulinum toxin is the most potent toxin known to man, with therapeutic dosages obviously below its LD50 - the original Botox contained 25 ng (ref) of botulinum toxin. Just to drive the point home, that's 10,000,000 times less than 250 mg.
  3. Hanstara
    or 5,000,000 times less than 125 Mg. ""Kind like breaking down a fraction"".
  4. Aminatrix
    Or to actually make it easier to understand, 1,000,000 times less than 25mg.

    Or 10,000 times smaller than 250ug for our microgram rc fans.


    If the laser was capable of delivering a constant stream at that intensity and level of control, it could easily be utilized in IV injection technology. However like someone above pointed out, you would need to ensure that continued exposure to this medium would not be toxic to the cells.

    Using the laser in it's current condition to inject say, 250ug of 25I subcutaneously... interesting although i don't know if it'd be effective.
  5. nigh
    I used 250 mg because it's a visual amount that most IV drug users are familiar with.

    The problem with utilizing a device like this continuously is many-fold. I used to be very interested in lasers (obviously the women loved me), and I can tell you that maintaining the very high wattages that pulsed lasers create (1 joule*250 microseconds is 40,000 Watts) is an immense challenge. Let's put this into perspective. You can cut decently thick steel with a 50W sustained beam CO2 laser. Not only would a continuous pulse 40kW laser amputate the arm someone's injecting in, it'd also take their monthly electric bills up quite a bit.
  6. source
    I find it impossible to try and imagine how a laser would be able to administer say, 0.8mL, intravenously, especially when the method at the moment is highly based on touch and feel. Not everyone has exactly the same type of veins, there are differences in condition, size and depth under the skin etc. For a laser to be able to judge all of this for itself before administering the drug intravenously would be pretty impressive and I'd have thought impossible.

    But then a year or so ago the above article would have seemed pretty impressive yet impossible..
  7. Gradient
    Wait wait, no one's talking about anything approaching 1J, they're talking about 1400mJ - and that's at the peak. Also, they didn't discuss any continuous delivery - just several shots staggered after each other at ~1hz. If you spread this over a wide surface area, it's really not appropriate to compare this to something like an IV drip.

    I see this technology as an alternative to transdermal delivery with solvents like DMSO or microinjectors. However, once the system is optimized for intravenous delivery - perhaps we'll then be talking about something comparable. Of course, that's assuming there's no destructive effect on vascular epithelium.

    nigh - I also suspected there may be some deleterious interaction with epithelial ECM components, but I don't see any problems if the mechanism is basically diffusion between epithelial cells. Do you have something more specific in mind, or are you just imagining type 1 collagen, integrins, stromal components ripped from epithelial cells?
  8. Hanstara
    Just think though of the future of medical tec.... We have gone so far... It was not very long ago that the first injection took place i think in 1840's or somthing ??? Fast forward to the future and you have all this new gear and high tec gadgets. I think the future of syringes might be with some other type of delivery system like the one mentioned. Just look at this picture of a older model, Kind of Barbaric.
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