Behind the scenes of the NU stem cell discovery

    Discovery is often just mixing things and hoping that the result is interesting or practical. So when researchers at Northwestern’s Stupp Laboratory added two liquids together, they were pleasantly surprised to find a possible boon to stem cell research.

    When simply brought into contact with each other, the two liquids oddly aligned themselves into a sac without the need for human intervention, making this discovery especially novel. The sac that they made can hold liquid, is bio-degradable, and so may in the future be used to hold stem cells that are then sent to different parts of the body to regenerate things like bone, tissue, or cartilage. Because of the nature of this strong new material than can fix itself, “there could be literally hundreds of applications” of the sac.

    In a phone interview, Professor Samuel Stupp, who led the research, explained the implications of this new material and its possible uses.

    NbN: How significant is this achievement for the lab in general? For Northwestern?

    Stupp: It’s extremely important. It’s a new way to make material.

    Why is the new material so important?

    It’s important for many reasons, but I’ll focus on one in particular, which is the possibility of encapsulating living cells effectively in a sac. Think of it like a balloon. They’re effectively bringing the cells, the liquid, in touch with another liquid. The balloons form instantly by a process of self-assembly and encapsulate the cells inside, but the walls of the balloon have properties that allow them to transport proteins and nutrients through so that the cells can stay alive for a long time. And it is very important to be able to confine cells in a specific environment, culture them in a three-dimensional environment, like a balloon. They can multiply and differentiate inside the balloon in a highly controlled way. It’s very valuable to be able to do that. For example, to differentiate cells for regenerative medicine.

    What’s been the medical application?

    Say you want to turn stem cells into bone or cartilage. You’d put them inside the sac for a few weeks, then transplant them. But [it wouldn't work] if you couldn’t culture them in a three-dimensional environment, where they’re completely isolated from other cells. But the balloon has the possibility where once you transplant the balloon, it’s strong enough to be repaired, like an organ. The balloon is also biodegradable: it will break down and then it will allow the differentiated cells to crawl out.

    The paper discussed “self-assembly.” Can you explain what that means? How do the materials do this on their own?

    Self-assembly means that you have molecules that are designed to interact with each other without human input. They organize themselves to make materials. So that means that you can fabricate a material without a human being actually putting it together or having a machine build the material. If you wanted to make a balloon out of material, you’d need very sophisticated equipment. In this case it just happens by bringing two liquids together, and anybody could do that.

    You were quoted as saying that this is “very difficult to get spontaneously in materials.” What does that refer to?

    That’s referring to the internal structure of the sac. It has a morphology that is very interesting and difficult to obtain without human intervention.

    You said that this was an “informed discovery.” How is that different from most discovery?

    ["Discovery"] means that we did not predict it, we did not expect it. But informed discovery refers to the notion that you have a certain amount of knowledge and you are bringing two things to interact with each other because you think between the two things, something could happen. And you know why that could happen, but you don’t know what will happen. We knew the interaction between these two liquids would be interesting, but we did not predict that they would lead to this three dimensional sac — it could have been something else.

    Is this an idea that other researchers in other labs will start to make and work with?

    Yes, they will probably follow our work, try to do similar work. Maybe change the parameters, innovate more or do something similar.

    Is your lab doing anything more with this right now?

    Yes, the lab is interested in working with this concept for other applications, like solar energy; also for other things, like bio-sensors and other things that are of interest to biology. There could be literally hundreds of applications. The structure that we got is an architecture that could be very interesting to make energy devices.

    Doesn’t it become frustrating when you spend months without solving a problem or having a discovery?

    Of course. The remarkable discoveries don’t occur very frequently. Most of the time it’s difficult to find interesting things. You can go for a long time before seeing something that’s promising. You have to be a very motivated person not to get discouraged when things don’t go very well.

    Why work in a lab, in science? I’m guessing it’s not the fame and fortune.

    Love of science. That’s what scientists do: we have curiosity and we want to understand how things work. That’s the nature. We’re also interested in discovery that’s useful, like for technology. We’re always thinking of ways –- not that we just think randomly about scientific problems — we think about specific problems in scientific areas that have relevance.


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