11/27/2013 04:28 pm ET Updated Jan 27, 2014

Soft Matters With Larry Bonassar

Q: What do the movies The Terminator, Starship Troopers, and Blade Runner have in common (besides being cult-classic sci-fi flicks)?

A: Each movie foresaw the use of artificial human tissue. The Terminator wore it (bad for his targets). The Troopers were healed with it (good for the soldiers). And any citizen or replicant could buy improved organs at the corner store (the sci-fi version of a book store's "self-improvement" section?).

My reason for bringing it up is this: just as Star Trek predicted the iPad 23 years ahead of the curve, these movies foresaw the reality of tissue engineering. And it's not in the future. It's here. Today. Right now.

This week on Soft Matters, Katie sat down with Prof. Larry Bonassar, whose efforts in studying cartilage (the soft connective tissue in your ears, nose, windpipe, spine, joints, etc.) are leading to breakthroughs in tissue engineering. A recent example of work to come from his lab uses a 3D printer to literally print an ear made from living cartilage. This proof-of-concept is exactly the idea that makes sci-fi movies like Blade Runner come to mind. Expect to see much more of this technology in the coming years.

Until then, be sure to watch the video:

Science-to-English Dictionary

Physics of Cartilage
In general, the physics of biological tissues draws on solid and fluid mechanics, their response to pressures (internal and external), and it even addresses questions about how each tissue is formed in the first place (morphogenesis). Cartilage in particular is interesting because fluid can flow through it and it has absurdly low surface friction. While it's tempting to say "physicists look at cartilage and ask one question, while biomechanicians look at cartilage and ask another" the reality is that the study of biological tissues is a highly interdisciplinary field. Distinctions like these don't matter. What does matter is that different disciplines all bring their own unique insight, and progress is made by collaborative efforts that build on one another.

Cartilage is made by cells called chondrocytes that spend their time producing the raw materials for cartilage synthesis. One idea from tissue engineering applications is to harvest living chondrocytes, culture them in a bioreactor, and coax them into growing fresh tissue for a transplant.

This is a measure of how "thick" a fluid is. For example, water has low viscosity compared to honey. More precisely, viscosity quantifies how rapidly energy is dissipated when the fluid is moved.

Surface tension
When molecules collide and interact, they can form clusters under the right conditions. From the macroscopic view this might be soap bubbles merging or oil and water separating. Both examples are driven by surface tension, which is used to drive a small boat in this example.