Microscope maps negative space to create 3D images

Areeba Khwaja

Microscopic biological materials are ready for their 3D closeup.

A new microscopy technique developed by UT researchers can visualize biological materials and other soft samples at the nanoscale level by 3D-mapping the space surrounding them.

Ernst-Ludwig Florin, lead researcher and associate physics professor, and Emanuel Lissek, a physics Ph.D. student, were able to successfully develop an imaging technique using a method called thermal noise imaging.

To better understand the process, they use the following analogy: Picture you have a tennis ball that is bouncing around in a room with an object. After a certain period of time, the ball will pass through all the space in the room except for the volume the object takes up. By collecting and combining a series of high-speed images from this moving ball, you can see the structure of the object.

To physicists, the tennis ball equates to a probe particle that moves by Brownian motion — the random motion of microscopic particles in a fluid.

“Essentially, the probe particle serves as a sensor to feel structures we want to image,” Lissek said, “We use touch sense, instead of only looking at objects with light and we can do so with very high sensitivity.”

Their research looks specifically at collagen, a plentiful structural protein found in connective tissues such as skin, cartilage and bones. Using their technique, Florin and Lissek were able to quantify how much collagen moves around within its natural environment of a tissue.

“This is important because its lets us study the mechanics of the entire collagen network,” Lissek said, “The mechanics on the microscopic level are what translate to the macroscopic level.”

Florin added that it can be extremely difficult to take images of biological samples, especially at the nanoscale level. Other imaging techniques require the cells to be fixed or chemically treated before they can be viewed.

“We are able to get information about the mechanics of cells without destroying [their] natural environment,” Florin said, “It’s at a spatial resolution that has not been achieved before.”

Lissek said this new method could be beneficial in understanding the elasticity of skin, developing artificial tissues and understanding the mechanics of cells.

“We are adding a whole new component that other technologies can’t do,” Lissek explained, “I’m excited to see what we can do with this in the future.”