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Injection innovation

A&M researchers develop material to target body parts

Published: Tuesday, February 4, 2014

Updated: Tuesday, February 4, 2014 23:02



Mike McShane (left) and Jason Roberts work to create localized vaccines.

Within the Biosensing Systems and Materials lab, Mike McShane, associate professor of biomedical engineering, and biomedical engineering graduate students Jason Roberts and Dustin Ritter have developed a new injectable material that could deliver drugs to targeted parts of the body.

The injectable material is composed of tiny microspheres encased in thin layers of nanofilm that are suspended in a hydrogel polymer.

The hydrogel, which is based on a polymer derived from algae, is injected into the body as a liquid. Upon injection, the microspheres change the liquid polymer into a soft, gelatinous solid. This allows the material to stay in one specific part of the body and constantly distribute the drug from that spot.

The microspheres also contain the drugs that can be distributed to specific parts of the body under conditions specific to the molecular makeup of the drug. The nanofilm acts as a membrane, regulating how much of the drug is released as the microsphere dissolves.

McShane said part of what makes the injectable material alluring for biomedical use is the biocompatibility of the hydrogel derived from algae and the microspheres made of calcium carbonate, a salt found in many antacids.

“One of the reasons this is so attractive to us is that it’s made from materials that are already considered pretty biocompatible, so the natural abundance of them makes it something that also is reasonably cost effective and sustainable long term,” McShane said. “We’re not concerned at this point about this particular material being something that relies on some rare product that may or may not be available forever.”

Ritter said with traditional drug delivery the drug gets distributed throughout the entire body. Not only is the drug being delivered to places where it isn’t needed, but also more of the drug has to be delivered because only a small fraction gets to the desired site.

“The advantage of targeted delivery is you’re not exposing every other organ system or tissue in your body to that drug, whatever that drug might be, and you’re also able to use much lower dosages because you’re delivering it directly to the intended site,” Ritter said.

Ritter said the lab has combined pre-existing methods in an innovative way that allows for a greater amount of control over the injectable material and its components.

“We haven’t developed a method to put proteins or nanoparticles into microparticles, we haven’t developed a method to put the coatings on those microparticles and we haven’t developed a method of turning that liquid alginate into a solid hydrogel,” Ritter said. “All of that has been done before. What we’ve come up with is a system that combines all of those different elements together in a synergistic way that affords a high degree of tunability.”

The hydrogel system could also be used to modify vaccinations and how they distribute antigens, which is the part of the vaccine that stimulates the immune system to protect against a particular illness. Using this system with a vaccine, microspheres could be used to hold antigens and release them over an extended period.

“Generally if you can get the body exposed to these antigens over a longer period of time, your body can deliver a better response to it,” Roberts said. “This system allows us to potentially encapsulate pieces of antigens and release them over a much longer period of time so when you get a vaccine it’s not just a liquid that gets cleared very fast, it’s a solution that can be released over a much longer period of time.”

Roberts said he has his ideas as to what the injectable material could be used for, but he is content so long as his work is being used.

“A lot of people work on things and they put them in their dissertation or they publish them and nothing happens — nobody picks up the idea and uses it for something else,” Roberts said. “I would be just as excited to see somebody else pick it up and use it for something that I hadn’t thought about before. That would be great.”


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