The Future of Medicine: Injectable Sponges and Foam

xstat-combat-injury-treatment-injectable-spongesMedicine may be advancing by leaps and bounds in certain fields – mind-controlled prosthetics and bioprinting come to mind. But in some respects, we are still very much in the dark ages. Considering gunshot wounds, for example. When it comes to modern warfare, uncontrolled hemorrhaging caused by a bullet is the biggest cause of death. In fact, “bleeding out” is responsible for 80% of deaths caused in battle, more than headshots, chest wounds, or IEDs combined.

This startling statistic doesn’t just apply to soldiers who are wounded in the field, as about the same proportion of those who sustain bullet wounds die after being evacuated to a medical treatment facility as a result of hemorrhaging. In the ongoing conflicts in Iraq and Afghanistan, about 5,000 US troops have been killed, and some 50,000 injured, while combined military and civilian losses are estimated to have been some 500,000 people killed.

xstat-combat-injury-treatment-injectable-sponges-5The immediate cause of death in most of these cases was bleeding out, which is usually associated with deep arterial wounds that simply cannot be treated using tourniquets. As a result, combat medics pack these wound with a special gauze coated with a material that stimulates the clotting process, then applies strong direct pressure over the wound in the hopes that a clot will seal off the artery. If the bleeding is not controlled, the medic has to remove the gauze and try again.

This process is so painful that, according to John Steinbaugh, a former Special Ops medic, the patient’s gun is first taken away so that he will not try to kill the medic or himself to stop the agony. And in the end, people still die, and all because medical science has yet to find an effective way to plug a hole. Luckily, RevMedX, a small Oregon startup, has developed an alternative approach to treat such potentially survivable injuries.

xstat-combat-injury-treatment-injectable-sponges-4That’s Revmedx and its new invention, the XStat, comes into play. Contained within this simple plastic syringe are hundreds of small sponges (1 cm, or 0.4 inches, in diameter) made from wood pulp and coated with chitosan, a derivative of crustacean shells that triggers clot formation and has antimicrobial properties. When they are injected into a deep wound, the sponges expand to fill the cavity, and apply enough pressure to stop arterial bleeding.

And since they adhere to wet surfaces, the sponges counter any tendency for the pressure to push them out of the wound. After conducting tests of early prototypes, the final development was carried under a US$5 million U.S. Army contract. In most cases, an arterial wound treated using XStat stops bleeding within about 15 seconds. The sponges are also marked with an x-ray absorbing material so they can be located and removed from the wound once surgical treatment is available.

????????????XStat is currently awaiting FDA approval, bolstered by a request from the US Army for expedited consideration. Combined with a new Wound Stasis Technology (aka. a medical foam) that earned its inventors a $15.5 million from the Defense Advanced Research Projects Agency (DARPA) back in Dec of 2012, army medics will likely be able to save a good many lives which in the past would have been written off as “casualties of war” or the all-too-common “collateral damage”.

Similar to the XStat, the idea for this injectable foam – which consists of two liquids that, when combined, form a solid barrier to stop bleeding – the inspiration for this idea comes from direct experience. As a military doctor in Iraq and Afghanistan, David King – a co-investigator of the foam project and a trauma surgeon at Massachusetts General Hospital – saw a great many deaths that were caused by uncontrolled internal bleeding.

DARPA-FoamLocated in Watertown, Massachusetts, Arsenal Medical designed this substance that consists of two liquids to fill the abdominal cavity and form a solid foam that does not interact with blood. This is key, since the hardened foam needs to remain separate and stop the blood from flowing. Comprised of polyurethane molecules, this foam belongs to a family of materials that is already used in bone cement, vascular grafts, and other medical applications.

The team began by testing the foam in pigs that were subjected to an internal injury that cut the liver and a large vein. With the treatment, nearly three-quarters of the pigs were still alive three hours later. Afterward, the team began monitoring how the pigs fared once the foam was removed. In 2013, the company began working with the U.S. Food and Drug Administration to determine how to test the technology on the battlefield (though no dates as to when that might have been available yet).

gun_violenceAs always, developments in the armed forces have a way of trickling down to the civilian world. And given the nature and prevalence of gun violence in the US and other parts of the world, a device that allows EMTs the ability to seal wounds quickly and effectively would be seen as nothing short of a godsend. Between saving young people for gang violence and innocent victims from mass shootings, NGOs and medical organizations could also save countless lives in war-torn regions of the world.

Source: gizmag.com, technologyreview.com, medcrunch.net

Nanotech News: Smart Sponges, Nanoparticles and Neural Dust!

nanomachineryNanotechnology has long been the dream of researchers, scientists and futurists alike, and for obvious reasons. If machinery were small enough so as to be microscopic, or so small that it could only be measured on the atomic level,  just about anything would be possible. These include constructing buildings and products from the atomic level up, with would revolutionize manufacturing as we know it.

In addition, microscopic computers, smart cells and materials, and electronics so infinitesimally small that they could be merged with living tissues would all be within our grasp. And it seems that at least once a month, universities, research labs, and even independent skunkworks are unveiling new and exciting steps that are bringing us ever closer to this goal.

Close-up of a smart sponge
Close-up of a smart sponge

Once such breakthrough comes from the University of North Carolina at Chapel Hill, where biomedical scientists and engineers have joined forces to create the “smart sponge”. A spherical object that is microscopic — just 250 micrometers across, and could be made as small as 0.1 micrometers – these new sponges are similar to nanoparticles, in that they are intended to be the next-generation of delivery vehicles for medication.

Each sponge is mainly composed of a polymer called chitosan, something which is not naturally occurring, but can be produced easily from the chitin in crustacean shells. The long polysaccharide chains of chitosan form a matrix in which tiny porous nanocapsules are embedded, and which can be designed to respond to the presence of some external compound – be it an enzyme, blood sugar, or a chemical trigger.

bloodstreamSo far, the researchers tested the smart sponges with insulin, so the nanocapsules in this case contained glucose oxidase. As the level of glucose in a diabetic patient’s blood increases, it would trigger the nanocapsules in the smart sponge begin releasing hydrogen ions which impart a positive charge to the chitosan strands. This in turn causes them to spread apart and begin to slowly release insulin into the blood.

The process is also self-limiting: as glucose levels in the blood come down after the release of insulin, the nanocapsules deactivate and the positive charge dissipates. Without all those hydrogen ions in the way, the chitosan can come back together to keep the remaining insulin inside. The chitosan is eventually degraded and absorbed by the body, so there are no long-term health effects.

NanoparticlesOne the chief benefits of this kind of system, much like with nanoparticles, is that it delivers medication when its needed, to where its needed, and in amounts that are appropriate to the patient’s needs. So far, the team has had success treating diabetes in rats, but plans to expand their treatment to treating humans, and branching out to treat other types of disease.

Cancer is a prime candidate, and the University team believes it can be treated without an activation system of any kind. Tumors are naturally highly acidic environments, which means a lot of free hydrogen ions. And since that’s what the diabetic smart sponge produces as a trigger anyway, it can be filled with small amounts of chemotherapy drugs that would automatically be released in areas with cancer cells.

nanorobotAnother exciting breakthrough comes from University of California at Berkeley, where medical researchers are working towards tiny, implantable sensors . As all medical researchers know, the key to understanding and treating neurological problems is to gather real-time and in-depth information on the subject’s brain. Unfortunately, things like MRIs and positron emission tomography (PET) aren’t exactly portable and are expensive to run.

Implantable devices are fast becoming a solution to this problem, offering real-time data that comes directly from the source and can be accessed wirelessly at any time. So far, this has taken the form of temporary medical tattoos or tiny sensors which are intended to be implanted in the bloodstreams. However, what the researchers at UofC are proposing something much more radical.

neural_dustIn a recent research paper, they proposed a design for a new kind of implantable sensor – an intelligent dust that can infiltrate the brain, record data, and communicate with the outside world. The preliminary design was undertaken by Berkeley’s Dongjin Seo and colleagues, who described a network of tiny sensors – each package being no more than 100 micrometers – in diameter. Hence the term they used: “neural dust”.

The smart particles would all contain a very small CMOS sensor capable of measuring electrical activity in nearby neurons. The researchers also envision a system where each particle is powered by a piezoelectric material rather than tiny batteries. The particles would communicate data to an external device via ultrasound waves, and the entire package would also be coated in a polymer, thus making it bio-neutral.

smart_tatoosBut of course, the dust would need to be complimented by some other implantable devices. These would likely include a larger subdural transceiver that would send the ultrasound waves to the dust and pick up the return signal. The internal transceiver would also be wirelessly connected to an external device on the scalp that contains data processing hardware, a long range transmitter, storage, and a battery.

The benefits of this kind of system are again obvious. In addition to acting like an MRI running in your brain all the time, it would allow for real-time monitoring of neurological activity for the purposes of research and medical monitoring. The researchers also see this technology as a way to enable brain-machine interfaces, something which would go far beyond current methods. Who knows? It might even enable a form of machine-based telepathy in time.

telepathySounds like science fiction, and it still is. Many issues need to be worked out before something of this nature would be possible or commercially available. For one, more powerful antennae would need to be designed on the microscopic scale in order for the smart dust particles to be able to send and receive ultrasound waves.

Increasing the efficiency of transceivers and piezoelectric materials will also be a necessity to provide the dust with power, otherwise they could cause a build-up of excess heat in the user’s neurons, with dire effects! But most importantly of all, researchers need to find a safe and effective way to deliver the tiny sensors to the brain.

prosthetic_originalAnd last, but certainly not least, nanotechnology might be offering improvements in the field of prosthetics as well. In recent years, scientists have made enormous breakthroughs in the field of robotic and bionic limbs, restoring ambulatory mobility to accident victims, the disabled, and combat veterans. But even more impressive are the current efforts to restore sensation as well.

One method, which is being explored by the Technion-Israel Institute of Technology in Israel, involves incorporating gold nanoparticles and a substrate made of polyethylene terephthalate (PET) – the plastic used in bottles of soft drinks. Between these two materials, they were able to make an ultra-sensitive film that would be capable of transmitting electrical signals to the user, simulating the sensation of touch.

gold_nanoparticlesBasically, the gold-polyester nanomaterial experiences changes in conductivity as it is bent, providing an extremely sensitive measure of physical force. Tests conducted on the material showed that it was able to sense pressures ranging from tens of milligrams to tens of grams, which is ten times more sensitive than any sensors being build today.

Even better, the film maintained its sensory resolution after many “bending cycles”, meaning it showed consistent results and would give users a long term of use. Unlike many useful materials that can only really be used under laboratory conditions, this film can operate at very low voltages, meaning that it could be manufactured cheaply and actually be useful in real-world situations.

smart-skin_610x407In their research paper, lead researcher Hossam Haick described the sensors as “flowers, where the center of the flower is the gold or metal nanoparticle and the petals are the monolayer of organic ligands that generally protect it.” The paper also states that in addition to providing pressure information (touch), the sensors in their prototype were also able to sense temperature and humidity.

But of course, a great deal of calibration of the technology is still needed, so that each user’s brain is able to interpret the electronic signals being received from the artificial skin correctly. But this is standard procedure with next-generation prosthetic devices, ones which rely on two-way electronic signals to provide control signals and feedback.

nanorobot1And these are just some examples of how nanotechnology is seeking to improve and enhance our world. When it comes to sensory and mobility, it offers solutions to not only remedy health problems or limitations, but also to enhance natural abilities. But the long-term possibilities go beyond this by many orders of magnitude.

As a cornerstone to the post-singularity world being envisioned by futurists, nanotech offers solutions to everything from health and manufacturing to space exploration and clinical immortality. And as part of an ongoing trend in miniaturization, it presents the possibility of building devices and products that are even tinier and more sophisticated than we can currently imagine.

It’s always interesting how science works by scale, isn’t it? In addition to dreaming large – looking to build structures that are bigger, taller, and more elaborate – we are also looking inward, hoping to grab matter at its most basic level. In this way, we will not only be able to plant our feet anywhere in the universe, but manipulate it on the tiniest of levels.

As always, the future is a paradox, filling people with both awe and fear at the same time.

Sources: extremetech.com, (2), (3)