Biopolymer Derived From Crustaceans Could Combat Military Mortalities | Chemical & Engineering News
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Web Date: March 27, 2015

Biopolymer Derived From Crustaceans Could Combat Military Mortalities

ACS Meeting News: Chitosan-rich spray foams can slow hemorrhaging from noncompressible wounds
Department: Science & Technology | Collection: Critter Chemistry
News Channels: Materials SCENE, Biological SCENE
Keywords: Chitosan, bandage, foam, polymer
Adding hydrophobically modified chitosan to blood creates a gel-like substance, as shown in this video.
Credit: Complex Fluids Group/UMD

A foam composed of a polymer derived from crustacean shells may prevent more soldiers from falling victim to the most prolific killer on the battlefield: blood loss.

Pressure is one of the best tools that medics have to fight bleeding, but they can’t use it on severe wounds near organs. Here, compression could do more harm than good, Srinivasa R. Raghavan of the University of Maryland explained Wednesday during a presentation at the American Chemical Society national meeting in Denver.

First responders have no way to effectively dam blood flows from these noncompressible injuries, which account for the majority of hemorrhagic deaths, Raghavan said.

Speaking in a session hosted by the Polymeric Materials: Science & Engineering Division, Raghavan announced that he and Remedium Technologies, a start-up company led by one of his former students, have developed a foam that the Food & Drug Administration is currently evaluating for use on noncompressible injuries.

Blood Foam
Hydrophobic components of the modified chitosan dock in blood cell membranes to help stop bleeding.
Credit: Biomaterials
Scheme of blood-loss-stopping mechanism.
Blood Foam
Hydrophobic components of the modified chitosan dock in blood cell membranes to help stop bleeding.
Credit: Biomaterials

The foam relies on chitosan, a biopolymer that comes from processed crustacean shells. By modifying the chitosan with hydrophobic moieties, Raghavan’s team gave the material the ability to anchor blood cells into gel-like networks, essentially forming blood clots. The researchers dispersed the modified chitosan in an aqueous solution to create a fluid they could spray directly onto noncompressible wounds.

Shell Game
Chitosan, derived from the shells of creatures such as shrimp, is an inexpensive and readily available material.
Credit: Shutterstock
Picture of shrimp.
Shell Game
Chitosan, derived from the shells of creatures such as shrimp, is an inexpensive and readily available material.
Credit: Shutterstock

As the solution sprays from an aerosol can, it traps bubbles of a biocompatible hydrocarbon propellant gas and begins to foam. The foam expands to cover the injury and block blood flow. Coupled with the modified chitosan’s coagulating effect, the foam can reduce blood loss by up to 90%, the researchers demonstrated during tests performed on pig livers.

Ankur Kulshrestha and Srini Sridharan, both of whom work in research and development for Bristol-Myers Squibb, said they organized the session in Denver to showcase research that could make an industrial impact. Innovation requires both good science and commercial potential, Kulshrestha said, and the new foam “is a very innovative product.”

Raghavan stressed that the foam combats blood loss—it doesn’t repair the injured tissue—but that it could help patients survive until a surgeon can more fully treat the damage.

“We really believe we have a material here that can find its way into emergency vehicles and even soldiers’ backpacks,” he said.

Chemical & Engineering News
ISSN 0009-2347
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Robert Allison (March 29, 2015 1:02 PM)
This sounds, on the face of it, to be what people suffering from HHT (Hereditary Hemorrhagic Telangiectasia) have been searching for. Most people with HHT, including me, have lots of serious nosebleeds daily or weekly. For example, I get 2 units of packed red cells IV every 2 weeks.

How can I buy chitosan foam/spray? A Google search has not yet found a retail source I can use.

Michael Castelaz (March 31, 2015 8:59 PM)
I thought exactly the same thing. This seems like something that would help reduce/nosebleeds of those suffering from HHT - almost like have a skin graft. I'm going to send this to our doctor and see what he thinks.
Matt Davenport (April 1, 2015 3:54 PM)
Hi Robert. As far as I know, the product is still being evaluated by the FDA and is not commercially available.
Alan Hawk (April 7, 2015 1:19 PM)
You might want to look at HemCon, which used Chitosan, or Quikclot Both have been used by the DOD during the Global War on Terrorism. I would contact the marketing departments as both products are for severe hemmorrhage.
Ruth E. Ulvog (March 29, 2015 4:41 PM)
Has anyone at this entity ever asked the following two questions????? 1) What happens when this is used on someone who is allergic to crustaceans but is unable to let medics know about that because he is unconscious??? 2) What happens if this is used on someone who is unaware that they have an allergy to crustaceans???

D. E. Courter (March 31, 2015 9:54 AM)
This is an interesting observation about a patient's sensitivity to the allergens in crustaceans.

At the end of the day however, if we can stop life threatening exsanguination, we have very effective countermeasures for anaphylaxis.

Obviously prior to release to the pre-hospital medical field this issue will need to be called out and addressed.
Irene Plotzker (April 1, 2015 2:05 PM)
That is clearly a concern. However, chitosan can also be made from fungi instead of using crustaceans. See, e.g., Lett Appl Microbiol. 2002;35(1):17-21.
Fungal chitosan production and its characterization.
Pochanavanich P1, Suntornsuk W.
John Hammond (April 1, 2015 2:45 PM)
Allergy is a small risk if the patient is rapidly bleeding out and likely to die if bleeding is not stopped. Perhaps the chitosan can be / or is stripped of most allergy inducing materials during its isolation and purification from crude shell materials.
Matt Davenport (April 1, 2015 4:19 PM)
Those are excellent questions, Ruth. I honestly don't know, but I've reached out to the researcher to learn more.
Edmund J. Stark (April 1, 2015 4:49 PM)
For a soldier who is about to die from blood loss, the two questions are irrelevant. If the person is not allergic, as is usually the case, this could save a life. If the person happens to be allergic, the only question then is whether an allergic reaction begins before death through blood loss occurs. Not a very important question.
Keith Faucher (April 2, 2015 12:59 PM)
Ruth - those are great questions. Since this biomaterial is a natural product the purity of the material (i.e. what residual process impurities are present) will greatly influence the allergenic risk of the material. In my experience with natural materials, protein residuals are often the culprit in causing an allergenic reaction in patients. Performing an extraction/hydrolysis of the material to isolate amino acids, labeling the amino acids with a tag and running it on an HPLC is typically one way to get an understanding of your residual protein levels. Therefore if you controlled your protein levels in your manufacturing process to a low enough level this risk could be mitigated, but you would still need to label the product with that risk even if that was the case. ISO10993 testing for medical devices includes an allergenicity assessment.
Matt Davenport (April 2, 2015 1:03 PM)
Raghavan says he doesn't think there is danger of serious immune responses to chitosan: "The material extracted from shrimp is chitin, which is then chemically converted to chitosan. Thus, chitosan is not present in shrimp. Chitosan is being used in many biomedical applications."
Sam Hudson (April 6, 2015 2:28 PM)
The proteins involved in the shell fish allergy are removed when the chitin/chitosan is isolated from the shells. Converting chitin to chitosan requires a treatment in 50% caustic at 130C, which should hydrolyze any proteins still present. Chitosan is a polysacharide with properties more similar to cellulose or starch. It has been used as a hemostatic in various forms for over 10 years, I think first as the Hemcon freeze dried pad.
John Riggs (April 1, 2015 1:36 AM)
My immediate thought, having served as Navy Corpsman in Viet Nam, and a paramedic for a large fire dept. is how do you get it off. For a long time it was thought that PAM kitchen spray was good for burns until I heard the patient screaming as the physicians in the E.R. tried to scrub it off.
Susan Parker (April 1, 2015 1:54 PM)
The product application may still be valid yet allergen issues do need to be taken into account. As this item is derived from shellfish, this would need to be reviewed before going into use.
Jennifer (April 1, 2015 2:31 PM)
@Robert You can't buy this yet; they are "currently evaluating for use." It does sound promising, and that's not a usage I would have thought of! @Ruth Absolutely. Evaluation includes monitoring for ANY potential adverse effects, including allergies. However, chitosan is not the chemical that causes shellfish allergy, so it is not likely a shellfish-allergic person will react. It is possible. But if somebody is already unconscious due to blood loss and the blood cannot be stopped by traditional means, there is a very high risk that they will die... so even if they *are* allergic, the benefit outweighs the risk and this stuff might still save their lives. An allergy could cause dangerous complications, just, less dangerous than the immediate loss of all of their blood. :)
Mke kwiecien (April 1, 2015 2:48 PM)
It is the protein found in the flesh of certain seafood that causes the allergy NOT the shells - especially after they have been processed to obtain the chitosan. So no threat to unconscious patients
Joseph T. Valko (April 1, 2015 3:26 PM)
If some of this foam gets into the victim's bloodstream, could it cause clots which might travel to vital organs? This would be a lesser concern compared with the victim bleeding to death, but a concern nevertheless.
Lisa Semmens (April 1, 2015 5:16 PM)
My questions are the same as Ruth's. As a person with an undiagnosed shellfish allergy who nearly died during a contrast procedure, it would make me nervous about the potential for anaphylaxis on top of the trauma to a severely injured patient.
Robert Buntrock (April 5, 2015 4:01 PM)
Others have pointed out that it's shellfish proteins that are the allergens, not the chitin/chitosan. As for medical warnings for first responders under any circumstances, those affected should wear a MedicalAlert Bracelet or medal. I do for my pacemaker.

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