Friday, June 18, 2010

Printing Out New Organs and Other Adventures in New Biology

It may not be long before severely burned persons will be able to lie back and watch while an entirely new skin is printed onto their body -- saving their lives.

The same printer technology that sits on your desk could soon be a common fixture in rebuilding human tissue, treating burns by laying down layers of a patients' own skin or even rebuilding whole organs.
A team at Wake Forest University has built a "bioprinter" that uses cells instead of ink. It even uses an ordinary, off-the-shelf printhead, connected to test tubes full of different cell types instead of wells full of colored inks.

Led by Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine in Winston–Salem, N.C., the team is working on treating burns. Such wounds can be hard to treat, because in severe cases there might not be enough healthy skin on the patient to harvest or culture for a graft.Grafting skin to cover burn wounds is also important for preventing infections, which can be a source of complications. Printing out cells grown in culture would eliminate these problems. Another application is repairing scar tissue.
The breakthrough in using bioprinting for tissue regeneration is the gel used to contain the cells: The mixture must hold the cells in place when they are laid down as well as provide a viable medium where they can be kept alive while they are held in the reservoirs. "It took us seven years," he says. "There's lots of trial and error; this isn't trivial chemistry," he adds.

For building tissue, several printing methods were tried, including three-dimensional CAD and laser printing. But once the group hit on the inkjet method, it turned out to work so well that some of the early work on building tissue was done on modified inkjet printers from a local office supply store.

Other organs have been constructed from cultured cells, but they were built on a scaffolding to give them their three-dimensional shape. Skin doesn't require a matrix because it is relatively flat to begin with.

So far, the system has been tested on mice, which are given wounds similar to burns. Those that were treated with printer-generated cells healed in three weeks, whereas those that were allowed to recover naturally required five weeks. The researchers plan to test the system on bigger animals in the future. The technology is still in the early stages, Atala says. As of yet there is no timetable for human tests or for the publication of the mouse research results.

The Wake Forest group is not just working on skin. Bone tissue and a two-chambered mouse heart have both been successfully printed. The heart was stimulated to beat when the cells were shocked with electricity, and the printed bones have been implanted in mice. _SciAm

Another approach to tissue regeneration is the use of biodegradable polymers as a scaffolding for the growth of replacement cells and tissues.

Here is an idea that is genuinely visionary -- which is exactly the sort of thinking we need to promote if we are ever to get to where we want to go. If we can take our biology to the level that allows us to grow living, breathing, thinking buildings that keep us comfortable and safe, imagine the level of accomplishment that human tissue engineering will have achieved.

A healthy, vibrant, and expansive society requires the best from all of its citizens. We cannot afford to be overly focused upon just one goal. We need to also be developing ideas and processes that may have no immediate use -- but which may indeed be earthshaking and earth saving sometime in the future.

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