The science of plasma-based materials (PBMs) is an interesting mix of biology and manufacturing. Pittsburgh-based Carmell Therapeutic (Carmell) is in the middle of that mix, developing PBMs that accelerate the healing of tissue injuries.

Carmell is currently in the process of commercializing The REPAIR™ Putty, a sterile and moldable PBM that is applied in a spackle-like fashion to open bone fractures. Surgeons can place the bone putty in the fracture area to fill voids left where bones have been joined by plates or screws.

Because PBMs are manufactured from human blood plasma, they retain their bioactive makeup, which consists of natural growth factors. This means that the PBMs have the capacity to accelerate the healing of bones and the surrounding soft tissue.

Loosely translated as “plasma-based plastics,” PBMs use human blood plasma as a starting point. From there, the manufacturing process mirrors that of most plastics. Jason Smith, Carmell’s director of research and development, explains the steps. “We begin with pooled units of blood plasma, which are freeze-dried to remove all water. The result,” he says, “is a flaky, protein-rich material that we grind into powder.”

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The powder is then processed into a dough-like material. Carmell uses compression molding to produce bioactive “plastics” in the form of flexible sheets, putties and more complex shapes, such as screws, the medical applications of which are still to be seen.

In contrast to synthetic plastic, PBMs bathe the damaged bone with a concentration of natural proteins and minerals, stimulating the body to repair itself. Because the material degrades over time, only the natural bone structure is left behind.

Many existing bone repair solutions rely on a supply of cadaver byproducts, but donor supply is a concern, and performance can vary significantly, explains Dr. Smith. “Ten batches of the same product will be derived from 10 different donors. Because the quality and biological makeup of each donor’s bone varies, the quality and makeup of each product batch will vary as well.”

Carmell’s differentiator is the use of pooled human plasma, meaning that the supply comes from multiple donors. This pooled plasma approach eliminates scarcity, and it also enables Carmell to maintain control over the consistency and safety of the plasma that will be manufactured into PBMs.

Cost savings is another benefit, since PBMs can be manufactured as a high volume, off-the-shelf product. This economy of scale significantly reduces the cost of REPAIR™ Bone Putty, which averages approximately $10 per milliliter, in comparison to a demineralized cadaver bone byproduct, which might sell for as much as $200 per milliliter. In addition to major clinical markets, this low-cost solution will open doors in developing countries, where cost has remained a barrier to treatment.

The technology behind plasma-based plastic was jointly developed by Carnegie Mellon University (CMU) and Pittsburgh’s Allegheny General Hospital. Carmell, a name play on the company’s CMU roots, was spun off in 2007 with the sole purpose of commercializing PBM technology.

Co-inventors of PBMs and founders of Carmell include Dr. Phil Campbell and Dr. Lee Weiss, renowned researchers at Carnegie Mellon’s Robotics Institute and experts in endocrinology and bioprinting, respectively, as well as Dr. James Burgess, a staff neurosurgeon at Allegheny General Hospital.

Carmell manufactures PBMs at its laboratory at Pittsburgh’s Institute for Transfusion Medicine.  The company’s pivot study for the REPAIR™ Putty, which is designed to validate patient success, is expected to begin next year. Once final FDA approval has been received, Carmell will commercialize The REPAIR™ Putty to help patients achieve better tissue healing outcomes.