In a quest for the perfect faux meat, labs are experimenting with a variety of technologies.
University of Western Australia avant-garde artist and tissue engineer Oron Catts has grown -- and tasted -- "steaks" grown from embryonic sheep and frog muscle cells. He and his collaborators have employed the so-called scaffold-based technique of growing lab meat.
A single layer of embryonic muscle cells is cultured on a thin sheet (usually made of starches or proteins) inside a bioreactor (a sort of lab-bench rice cooker that incubates the cells while keeping them sterile). The scaffold makes it easy to nourish every cell -- which is challenging when growing chunks of flesh because cells in the middle will die without a blood supply.
In a display at a biotech art exhibit held in France in 2003, Catts grew, over three months, muscle cells from a tadpole. The bioreactors yielded two "coin-sized" steaks, which Catts and collaborators flambeed in brandy and ate.
Other researchers have experimented with the scaffold method, first developed by scientists in the Netherlands. (The Dutch government has invested more than $2 million in efforts to produce in vitro meat.)
But tissue engineering expert Paul Kosnik of Tissue Genesis Inc., a biotech company in Honolulu, says the technique falls short of producing viable meat substitutes because it reduces meat to one layer of muscle cells without the fat and connective tissue so critical to chewiness. The result, he says, is flesh that tastes like "steak-flavored jello."
Kosnik and his colleague Bob Dennis, a tissue engineer at University of North Carolina in Chapel Hill, have developed a method to get around the jello problem that creates a three-dimensional tissue. The labor-intensive process, which they've tested extensively with mouse and rat muscle, begins with two cell types, fibroblasts and myoblasts. The cells are nourished and incubated but are also attached to artificial tendons, which cue them to grow into the shape of the long, thin fibers found in animal muscle.
The muscles are also "exercised" to firm them up, by stimulation with electrical currents.
The resulting tissue contains muscle and connective cells arranged and shaped as they would be in a warm-blooded animal -- and once you've got all that, "then the taste, texture and other elements that are important for in vitro meat are also there," Kosnik says.
So far, neither Kosnik nor Dennis has tasted the results.