In 1888, an Austrian botanist dissected a carrot and today, we have LCD TVs. That’s the thing about science, you never know where it will lead.
That botanist was Friedrich Reinitzer, and he observed cholesterol extracted from a carrot that behaved both like a liquid and a solid. It was the first observation of a liquid crystal. Over the next century, it spawned a new field of research and countless technologies.
Would Reinitzer’s research be funded today?
With funding down and competition up, researchers have to fight for every dollar. Even fundamental researchers — the scientists who explore the basic building blocks of life and matter — are often asked to predict how their research could be applied.
At Brandeis, researchers build the foundations for curing disease, developing clean energy and understanding the cosmos. The research goal may be identifying how a particular protein operates in the disease process, or which chemicals won’t act like greenhouse gases in the atmosphere. But we also celebrate research that explores an unknown frontier without knowing where it will lead.
Physicists Zvonimir Dogic and Michael Hagan are doing just that.
Recently, their research into two-dimensional physics was featured in Nature, one of the most respected journals in science. The paper was also authored by Brandeis University graduate students Prerna Sharma and Andrew Ward. Knowing just how their research will be applied is decades down the road. But that doesn’t diminish the cool factor; indeed maybe it heightens it.
In the three-dimensional world, oil and water separate when combined. The smaller droplets of oil merge with larger ones, eventually forming one continuous layer that floats on water.
It’s a basic principle in physics.
But in the two-dimensional world, things work very differently.
Take our cell membranes, a two-dimensional liquid world. Liquid lipid “rafts” float on the surface of membranes, carrying proteins and regulating transport in and out of the cell.
If the lipid rafts behaved like liquid in the three-dimensional world, the individual rafts would coalesce into one larger raft.
But, as the researchers observed, the 2-D world has its own operating system.
To get an inside peek at this microscopic world, Dogic and Hagan needed to scale up, big time. They used long rod-like viruses to create a colloidal membrane — a membrane made up of thousands of smaller particles — like our cell membranes except much, much larger.
To build the lipid rafts, they used shorter rod-like viruses.
When the team put the shorter and longer viruses together, something unexpected happened: instead of separating like oil and water, the short rods self-assembled into smaller droplets of equal size and shape.
And they held that size and shape. Even when the sample started out with different sized droplets, they all equalized.
Even when the team split a droplet, it returned to its original size a few hours later.
Dogic and Hagan discovered droplets don’t coalesce because they actively repel each other, like magnets flipped on one side. A droplet’s chirality — the way its component rods twist in space — creates a distortion in the membrane, which its fellow droplets want to avoid. The effect is long-range, with the droplets avoiding each other as far as 10 diameters away.
The droplets constantly exchange and rearrange their rods to maintain the same size.
In the 3-D world this just doesn’t happen, but our rules don’t apply to the 2-D world.
Dogic and Hagan also discovered that by tweaking the parameters of the droplets — their chirality, for example — they can assemble into different shapes, like long, polymer-like strings or horseshoes.
So what does this all mean?
It means we’re just beginning to lift the curtain on the two-dimensional world. Sure, Dogic and Hagan can speculate about applications like self-healing fabrics or new drug delivery systems, but right now, it’s just cool science. No, it’s fundamental science. And that’s cool.