February 11, 2010 – Original Source: Danger Room, WIRED
The Pentagon’s scientific fringe want to fast-track the quick and easy repair of wartime wounds, by eliminating one of the most important elements of tissue engineering – and replacing it with magnetic fields.
Last year, Darpa-funded researchers successfully generated human muscle tissue, and the agency requested proposals for a device that could pump out new body parts made with adult stem cells. Now, Darpa’s next-gen military medicine mission continues: the agency’s budget for the upcoming year includes $6.5 million for the creation of a scaffold-free tissue engineering platform, which would allow the construction of “large, complex tissues in vitro and in vivo.”
Tissue engineering has been around for years, and researchers have made major progress in the last decade. They’ve created lab-grown collagen, artificial bladders and even reconstructed damaged rabbit penises. But all of the progress has taken place with scaffolds: artificial platforms that provide structural stability while cells develop their own matrix, and eventually turn into fully functional tissues, organs, muscles, and even body parts. Dozens of different scaffolding methods have been developed, but all come with inevitable drawbacks. Usually, as Darpa notes, scaffolds can’t sustain tissues larger than 2-3 square millimeters, and it can be difficult to control how cells will react to the scaffolds, especially inside a living organism.
Instead of improving on scaffolds, Darpa wants to do away with them altogether, which would be a paradigm shift for tissue engineering. It’ll also require some major innovation. Last year, a research team at the University of Missouri and Yale tried to create tissue using agarose (a gel derived from agar) rather than a scaffold. They noted “major limitations,” and doubted cell viability in a lab environment, let alone a living organism.
Rather than replacing scaffolds with another substance, Darpa’s after “non-contact forces,” like magnetic fields or dielectrophoresis. The forces would control cell placement “in a desired pattern for a sufficient period of time to allow the cells to synthesize their own scaffold.” Without the limitations of scaffolding, it would be easier to create multi-cellular tissues, both in a lab and in the human body.
Darpa’s long-term objective is to reconstruct wounds in the war-zone, without the need for intensive surgery or the implanting of a specially-designed scaffold. In the short-term, they’re looking for a research team to develop a fully functional skeletal-muscle construct, complete with blood flow and a nervous system, in an animal model.