Man-made cilia have shown that the real structures create complex flows of fluid that may contribute to normal development and tissue differentiation in early embryos, according to researchers at the University of North Carolina at Chapel Hill, reporting their findings in PNAS.



Richard Superfine, a biophysicist at UNC, lead a team of researchers hoping to more completely explain how a ciliated area called the embryonic node aids in the formation of separate germ layers and in the development of a right-left axis in the embryo.

"In order to understand these biological situations, we would have to make our own model and make precise measurements on what the fluid flows were like," Superfine told The Scientist.

Superfine added that his group has so far created the model -- made from magnetic nanoparticles mixed with a substance similar to window caulking -- that best mimics the size and spacing of real cilia in developing embryos. In this model, fluids flow as if carried along by a river's sweeping current above the tips of cilia, but beneath the cilia's tips, fluids are mix, almost as if by simple diffusion. This new information, Superfine said, can help biologists understand how signaling molecules released at the embryonic node are transported in the embryo, given that molecules will follow a different path depending on where they are released. "In the end it gives real insight into how chemicals are released into this region of the nodal plate and then how they are sensed," he said. The establishment of chemical gradients, he added, which are crucial to the progression of normal development and differentiation, might not be possible without the rhythmic pulse of the cilia.

"It's very nice work," said Julian Vincent, a professor of mechanical engineering and the chair of biomimetics at the University of Bath in the UK, who was not involved with the research. "Here we have yet another mechanism which is used to generate shape in animals."





Related stories:

Eyelashes Up Close
[July 2010]

Airway cilia taste toxins
[23rd July 2009]

Chasing the Cilium
[11th October 2004]