Hi, everyone. Welcome to the A16Z podcast. I'm Hannah, and today's episode continues our ongoing

series on how science becomes engineering and all the new challenges and opportunities that

presents as people move across fields and into new mindsets. It's a conversation between A16Z

general partner Vijay, who heads up our bio fund, and Bob Langer, Institute professor at

MIT, whose work has really been all about the interface of engineering and materials in biology

and medicine. So, Bob, your work has been a very unusual blend, right? From chemical engineering

to medicine, to biotech, what are some of the ways or some of the

problems that you thought about and approached differently given that less traditional

background?

One of the things that I noticed because I was working with materials myself were how did

materials find their way into medicine?

And what I'd see is almost all the time, what happened is somebody was, some clinician

wanted to urgently solve a medical problem. And what they do is they'd go to their house

to find some object that would kind of resemble the organ or tissue they wanted to fix. And then

they'd use it in a person. Amazing.

If you want to make artificial heart, what the clinicians did in 1967 is they said, well, what object in your house has a good flex life like a heart?

And they came up with the idea of a lady's girdle.

So they looked at what that was made out of, and it's a polyether urethane.

And then they decided they'd use the exact same material to make the artificial heart.

That was 1967, but now 50 years later, that's still what it's made out of, because once you start down that path from like a FDA regulatory standpoint, it's hard to change.

And, of course, the artificial heart has run into

different kinds of problems. In particular, one of the problems has been when blood hits

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