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Alginate Hearts

Question: What do you get when you combine seaweed and modern technology?

Answer: Squishy gels and a human heart!

OK, technically it’s a heart model. Yet down to the size, feel, and inner workings, it mimics the real thing.

A team led by biomedical engineer Adam Feinburg at Carnegie Mellon University designed the heart model using a technique called Freeform Reversible Embedding of Suspended Hydrogels (FRESH). The results were published last October in an ACS Biomaterials paper.

The hearts are made out of alginate, a material found in seaweed that has been lauded for its medical possibilities. Under relatively mild conditions, alginate can be made into a hydrogel substance that resembles soft tissue. Not only does the material hold up well —it is inexpensive and easily found in nature.

[Photo source: How an MRI scan becomes a 3-D printed alginate heart. Source: WIRED]

Printing a PDF is a straightforward matter: it is the application of ink on a two-dimensional surface. Printing a heart, in a way that replicated its spongy texture, intricate passageways, and three dimensions, required some tinkering. In previous renditions, 3-D printed soft-tissue materials lacked support and collapsed upon printing.

Using the FRESH technique, Feinburg and his team printed the soft biomaterials within a gelatin bath. Since 3-D printers work by depositing layers of material on top of one another, the bath acted as a support structure while printing. Once set, scientists used heat to melt away the gelatin lattice, and voilà: a human heart!

Most existing heart models in hospitals are rubber or plastic-based, which decidedly don’t behave like natural tissues. In contrast, with the elasticity of the FRESH model, “it deforms the same amount” as a real heart. This means that surgeons can train and practice before cutting into a patient, which will lead to more successful surgeries, said the team.

The team also 3-D printed a section of coronary artery. Then, they filled it with fake blood. The blood did not leak from the alginate artery, which could potentially grant surgeons the ability to suture real arteries while blood is flowing.

Feinberg and his team recognize that the technique is still in its fledgling stages, but that it could well be applied to other organs such as the kidney or liver. As for a fully operational, ready-for-transplant, 3-D printed human organ? Feinberg first has to find a way to make 100 billion heart cells — to make the heartbeat. “The answer is more than 10 years.”

So, right around the corner?

Whether an alginate or MANIKEN® model from the Anatomy in Clay® Learning System, both models reinforce that the “Mind cannot forget what the hands have learned.™”

So when building the heart with Anatomy in Clay® Learning System in the classroom (and the clay system makes it possible for you to get as detailed as you want!) know that the difference between the manmade version and the real thing is getting closer and closer every day.







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