Researchers create mathematical model of frui...( EVANSTON Ill. --- Many researchers h...)

EVANSTON, Ill. --- Many researchers have tried to create a mathematical model of how cells pack together to form tissue, but most models have many different complicated factors, and no model is universal.

Researchers at Northwestern University have now created a functional equation -- using only two parameters -- to show how cells pack together to create the eyes of Drosophila, better known as the fruit fly. They hope that the pared-down equation can be applied to different kinds of tissues, leading to advances in regenerative medicine.

Sascha Hilgenfeldt, associate professor of engineering sciences and applied mathematics and of mechanical engineering in the McCormick School of Engineering and Applied Science, teamed up with Richard W. Carthew, professor of biochemistry, molecular biology, and cell biology in the Weinberg College of Arts and Sciences, and Sinem Erisken, a McCormick undergraduate studying biomedical engineering, to create the model. Their work was published online Jan. 11 by the Proceedings of the National Academy of Sciences (PNAS).

The interdisciplinary effort among geneticists, engineers and mathematicians began 18 months ago, when Hilgenfeldt, who specializes in foam, soft matter and fluid mechanics, teamed with Carthew, who has studied the biological features of fruit fly eyes.

Hilgenfeldt knew that when it comes to creating a model that shows what determines the shape of functional cells in tissues, the myriad factors -- including the bulk of the cell, whats going on inside of the cell and how the cell forms -- make it very difficult to quantify.

Thats a nightmare for quantitative scientists, he said. Its extremely complicated.

But the cells in a fruit flys eye act more like foam in that the structure of the cells depends only on the energy of their interfaces, or the surface where the cells touch. That energy is divided into two parts -- the energy from the stretching of the cells mem
'/>"/>