(Phys.org)—Tiny cellular structures called cilia play a crucial role in a variety of bodily functions, including fluid movement, sensing the environment, and cell signaling. Researchers have long been interested in understanding how cilia work, but their complex structure and behavior have made them difficult to study.

Now, researchers at the University of California, Santa Barbara have developed a new way to study cilia using high-speed microscopy. Their findings, published in the journal eLife, provide new insights into the mechanics of cilia and how they generate movement.

"Cilia are these little hair-like structures that stick out from the surface of cells," said Melissa Zhang, the study's first author and a graduate student in the Department of Molecular, Cellular, and Developmental Biology at UC Santa Barbara. "They're really important for a lot of different functions, but we don't fully understand how they work."

One of the main challenges in studying cilia is that they are very small, typically only a few micrometers in length. This makes it difficult to see them clearly using traditional imaging techniques. To overcome this challenge, Zhang and her colleagues used a specialized type of high-speed microscopy called differential interference contrast (DIC) microscopy.

DIC microscopy uses polarized light to create a high-contrast image of the sample. This allowed the researchers to visualize the cilia in much greater detail than was previously possible.

In addition to using DIC microscopy, the researchers also developed a new way to prepare the cilia for imaging. They used a technique called super-resolution photoactivated localization microscopy (PALM) to label the cilia with fluorescent molecules. This allowed them to track the movement of the cilia over time.

Using these new techniques, the researchers were able to make several important discoveries about cilia. They found that cilia are made up of a series of repeating units called axonemes. Each axoneme consists of a microtubule doublet, which is a pair of microtubules that are connected to each other.

The researchers also found that the cilia move in a wave-like fashion. The waves are generated by the microtubule doublets, which bend and straighten in a coordinated fashion.

"We were able to see that the cilia move in a very specific way," said Zhang. "They bend and straighten in a wave-like pattern, and this is what generates the movement of the fluid."

The researchers' findings provide new insights into the mechanics of cilia and how they generate movement. This could lead to a better understanding of a variety of diseases that are associated with cilia dysfunction, such as primary ciliary dyskinesia (PCD) and polycystic kidney disease (PKD).