May 19, 2020

Quantum biology: going subatomic

By Conor McKechnie and Dodi Axelson

Quantum biology: going subatomic

How do birds know where to go in the winter? And why are plants so efficient at making food? Dodi and Conor chat with researchers studying whether quantum biology might come into play.

CONOR: Dodi, just a quick note on the audio here. Obviously, we're all working from home, as are all of our interviewees. So, the quality is not what we would really want in a podcast. I think that means a big credit to our producer as well. Thomas is doing a great job with the audio that we are able to record. With that, on with the episode.

We're going to go into some really hardcore science today. What comes to your mind when I say quantum physics?

DODI: Well, I think about that old TV show Quantum Leap. Do you know it?

CONOR: I do know it. It was absolutely fabulous. And it was Dr. Sam Beckett, traveling all around the universe in time and space, solving difficult riddles and problems.

DODI: And his main advisor was a hologram.

CONOR: That's exactly right. And that's not what we're talking about today.

DODI: What are we going to talk about today?

CONOR: Well, the thing is, this is the problem with science fiction in popular culture. You get a word like quantum, it sounds woowoo and amazing. And suddenly, you can get quantum everything. You can get quantum bananas and quantum underpants and quantum leaps. But they don't actually use the word in the sense that it's meant. And that's a natural thing in language. But what we're talking about today is quantum biology. It’s a fairly recently emerged field in terms of the popular understanding of it, but it goes back to 1939 at least. And that's what we're going to be talking about today.

DODI: And that seems to be what matters on today's episode.

CONOR: It does.

And I'll throw in a long preamble. Let's go back to an Austrian physicist fleeing Nazi Germany for Ireland to help establish the Institute for Advanced Studies in Dublin. This is Erwin Schrödinger. Schrödinger published a book in 1944 called What is Life? He was looking at how events in space and time take place within the spatial boundary of a living organism. How can they be accounted for by physics and chemistry?

A couple of decades later in 1962, the Nobel Prize in Physiology and Medicine was shared by Watson, Wilkins, and Crick, for the discovery of the structure of DNA. All these guys were physicists, and all credit Schrödinger for inspiring their work. And in fact, Wilkins went as far as to say that it was Schrödinger that made him want to become a biophysicist. So, I went to the University of Surrey in the UK to speak to two researchers in quantum biology.

SAPPHIRE: The idea with the stability of DNA, and this was Schrödinger's original hypothesis, is that you need some kind of additional ordering principle on top of the thermal ordering that you'd normally expect to see in order to keep the level of mutation so low. His original hypothesis was that quantum mechanics can be like an ordering rod for DNA. The original idea certainly was that thermal ordering alone should give us 10 000 times more mutations than we currently see. And it still is very much possible. We have some research currently ongoing in our center that DNA repair enzymes could have quantum mechanical action within them.

DODI: So who's that?

SAPPHIRE: My name is Sapphire Lally. I'm a theoretical physicist working in the quantum biology research group. I look at modeling open quantum systems that could potentially be applied to biological systems.

CONOR: And along with Sapphire to tell this incredible story, we also have...

EDELINE: I'm Edeline D'Souza. I am an experimental biologist. I'm looking into avian magnetoreception or animal magnetoreception and how quantum mechanics might be playing a role in how animals detect the Earth's magnetic field.

DODI: Okay, so give us this story about quantum biology.

CONOR: So firstly, it's immortal. To understand the difficulty with respect to quantum biology and the reason it isn't much more of an established field today, there's been a lot of work done. But it's only in the last few years that there's been established growing evidence for specific mechanisms within biological cells that make use of quantum mechanics to actually happen.

SAPPHIRE: Biology is not a natural place to look at quantum mechanics, because these are complicated, warm systems. And usually when we see quantum mechanics happening, it's fairly cold, simple systems. In general, the warmer your system, the shorter the length of relevant quantum effects until for really big systems, the quantum wavelength as it were, is much smaller than the item itself. So, it doesn't get anywhere useful.

DODI: So, operating as close as we can get to absolute zero.

SAPPHIRE: Yes, essentially.

CONOR: And that's the issue. You're doing science at absolute zero if you want to understand what's happening in the quantum world. But biological systems, as we all know, are all warm and wet and difficult. So how can you study warm, wet things at a quantum level, where it just doesn't seem that quantum phenomena would naturally happen or have an effect?

The contrast between quantum physics and biology is not just to do with the fact that people understand quantum physics as dealing with the science of the very, very small.

DODI: The subcellular and the submolecular.

CONOR: Yeah, and even smaller. But it's also to do with the fact that people see quantum effects being done in science at very, very cold temperatures, and biology happens in warm things.

DODI: And we are about to do an episode on very, very cold temperatures, cryobiology.

CONOR: That episode is coming up.

DODI: So, if quantum biology really is a thing, if quantum theory and quantum effects are visible, observable things in biological systems, how come there's less attention being paid to it?

CONOR: Sapphire says there are a couple of reasons, and they mostly come from hostile or grating attitudes between groups of scientists.

SAPPHIRE: Physicists, in general, we like to simplify things as much as possible so we can do maths about them. Biology is a horrifyingly complex mix of systems, and it's very daunting to think about applying our techniques, which we typically reduce systems down to as many components as possible. On the other hand, biologists sort of think, "Well, we've done this quite well for quite a long time without you needing to get involved." And in general, it seems quite unrealistic in some way that quantum mechanics could play a role in biology because all the quantum systems we're familiar with are incredibly cold, incredibly simple, whereas biological systems are complicated.

CONOR: And this is not just esoteric theorizing. Sapphire and Edeline are looking at practical applications of the work. There are two solid examples that show how quantum mechanics is playing a role in biology. Those are magnetoreception and photosynthesis. In magnetoreception you're familiar with the idea that birds can seem to find their direction when they travel south for the winter, and so on. And the theory was that they have lumps of magnetite in their brains that allow them to sense the lines of magnetic force around the world, right? But when scientists actually looked for evidence of magnetite or magnetic material in the brains of birds that migrate, it was very notable in its absence. So, the question is, how is this happening?

EDELINE: I think both of these have quite interesting downstream applications, because understanding them at a more fundamental level will allow us to potentially come up with more technologies or a better understanding of what is going on at these warmer temperatures. And then we could have either biotechnology or potentially even quantum computing applications down the line.

DODI: So Sapphire and Edeline have mentioned magnetoreception and photosynthesis. What is it that biology cannot really explain about them, but that quantum biology seems to be able to define?

EDELINE: Photosynthesis is a very efficient process. Once the light is absorbed by a photosystem it manages to convey that energy to a very, very high degree, much higher than most current photovoltaic cells and the mechanism that they use. Originally, the idea was that it did a random walk.

DODI: Okay, keep talking me through this. I'm not there yet.

CONOR: So, think of a traveling salesman. If a traveling salesman walks along from place to place randomly, trying all the different routes that they could eventually go by, to find the most efficient way to have the most success, that is going to be a really inefficient way of optimizing their journey, right? The thinking here is that if you think of the packets of energy that photosynthesis is delivering to the system as it were, to the plant, that these packets of energy or this traveling salesman, they explore every single possible way simultaneously.

EDELINE: That makes more sense efficiency wise, and that is one of the ways that quantum biology could potentially make sense. Because if we can use that understanding to create more efficient solar cells, we could really, really increase the amount of energy that we can harvest from the sun and make solar energy super cheap, definitely more efficient.

DODI: Well, that is just spectacular. It's completely amazing. So, we see this incredible system in place that has evolved over millions or billions of years. And to assume that we'd be able to create exactly the same thing in an electrical system could be seen as...

CONOR: Maybe just a little bit arrogant.

DODI: Just a touch.

CONOR: But just think about what it could mean if we could create solar cells that were as efficient as trees in converting sunlight to energy. Think of the revolution in energy.

DODI: So what Sapphire and Edeline are saying is that if we can understand what's actually going on in this extraordinarily well developed system that has evolved through evolution, maybe we could create much more efficient versions of that for our own use, like those solar solar panels that you're talking about.

CONOR: Exactly.

DODI: So that's photosynthesis, but what about the magnetoreception? What can be explained there that cannot be explained by biology?

CONOR: Here's Edeline again.

EDELINE: In biological systems, a lot of the complexes that we work with are hugely stable. They are polymers, they've got really strong bonds between them. What's always been missing in the magnetoreception investigation is the absence or sort of latentness of anything that's ferrous that can be used in a magnetosensory way.

CONOR: People hypothesized that there must be some form of magnetic sensitive material in the brains of these birds. They went looking for these magnetic materials, and they found nothing.

EDELINE: Yeah, nothing's been found so far. And that was always a bit of a mystery. And then using a well-established type of reaction from spin chemistry, there was a proposal for this model that could potentially be occurring in a biological system. When this protein, this biological molecule, absorbs a photon of light it pushes it to an excited state so it elevates the energy in the system. And that causes it to split into two component parts to radicals, which are components that have a lone electron. So, an electron that is unpaired. And this makes it a lot more unstable. This instability makes it more vulnerable to sensing the Earth's magnetic field. And that's where quantum biology comes in for magnetoreception. If we understand what's happening in this mechanism, we could potentially use mass magnetic fields to control biology or expression of genes and proteins. We can use that as a therapeutic as well.

DODI: Fascinating stuff.

CONOR: As we see from Edeline's example, suddenly we've not just got potential explanations of what's going on, but also real practical explanations of what's going on and how potentially they could be applied in real life applications.

So that is the argument to help silence the naysayers. But what is the reaction in that community, the biologists that have said, "Hang on, this is our field, hands off. We don't need you guys."

SAPPHIRE: That's a very interesting question. Because if you boil what I do down into nonbiological terms, I look at room temperature, open quantum systems. And if we can model room temperature, open quantum systems that have long-lived quantum effects, that's a hugely useful thing for a massive range of applications. So, there's definitely a range of applicability. On the other hand, people are quite dubious, I think, that room temperature quantum effects could ever be long-lived enough.

DODI: So, they're not saying the quantum effects don't happen at room temperature. They're saying the quantum effects are so small at room temperature, that they wouldn't have any effect on these large, warm biological systems, the wet systems you were talking about.

CONOR: That's exactly right.

DODI: I have to say bravo to them both. Everybody wins, not only for the hopes of the future that their work displays, but also for the challenge of it all. I mean, there seems to be a lot of friction in and about and towards their work. So, what is it exactly that drew both Edeline and Sapphire into such a niche field?

SAPPHIRE: I think I like the challenge of having to describe something that exists independently from me, whereas the laws of quantum mechanics are about designing rather than describing, if that makes sense. If my system is too hot, then I say, "Okay, well, let's just cool it down." Whereas I can't do that, I have to work with things I can't change. And I think I really enjoy the challenge of that.

EDELINE: Physics has always been one of those things that is from the outside, at least, super elegant. You get to explain different systems, and I've always had an appreciation for it from a more conceptual maybe rather than mathematical standpoint. I, however, am a biologist. And so that's always been a very spare time hobby interest. When I found out that quantum processes could be happening in biological systems, it definitely piqued my interest. And then I started looking into it a bit more. And I think the more you look into it, the more intrigued you get. And over time, some of it can manifest as a frustration, but it's like a problem that you kind of want to sink your teeth into.

CONOR: Before we go, I think it's important to note that both Edeline and Sapphire are adamant that interdisciplinary discussion and collaboration is how these fields move forward, and that sometimes biologists and physicists do butt heads and don't agree. But if they work together, they can make real progress.

SAPPHIRE: There are definitely pockets where being niche is fine, and you can do your own thing, and you won't really have to ever talk to someone from a different field. But in general, not having tunnel vision is a good thing. If I have a specific research interest, and I can find people who would traditionally be from another research group, and we can work on that problem together, then we have a much broader range of tools to attack that problem. That is fantastically helpful, because sometimes you don't even have the language to talk about what you don't know.

CONOR: So, there you go.

DODI: I think we all are happy together, yeah?

CONOR: Isn't it extraordinary? Physics and biology, you thought that they were completely separate. And we are seeing things like magnetoreception, we're seeing things like photosynthesis. We're even seeing things like the sense of smell being explained by quantum phenomena.

DODI: The internet of smell.

CONOR: Wouldn't that be cool?

DODI: I can't wait.

CONOR: So, rate us on your favorite podcast app, and we look forward to next time.

DODI: Thanks for listening.

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