Simple model cell is key to understanding cell ...( A team of Penn State researchers has...)

A team of Penn State researchers has developed a simple artificial cell with which to investigate the organization and function of two of the most basic cell components: the cell membrane and the cytoplasm--the gelatinous fluid that surrounds the structures in living cells. The work could lead to the creation of new drugs that take advantage of properties of cell organization to prevent the development of diseases. The team's findings will be published later this month (late May 2008) in the Journal of the American Chemical Society.

"Many scientists are trying to understand cells by turning off genes, one at a time, and are observing the effects on cell function, but we're doing the opposite," said Associate Professor of Chemistry Christine D. Keating, who led the research. "We're starting from scratch, adding in components to find out what is needed to simulate the most basic cell functions. Our goal is to find out how much complexity can be observed in very simple collections of molecules."

Building on previous work that was published in the 16 January 2008 issue of Journal of the American Chemical Society, Keating and her colleagues built a model cell using as the cytoplasm a solution of two different polymers: polyethyleneglycol (PEG) and dextran. The researchers encapsulated this polymer solution inside a cell membrane and, because the two polymers do not mix, one of the phases surrounded the other like the white of an egg around a yolk. The team then exposed the cell to a concentrated solution of sugar. Through a process known as osmosis--in which water diffuses across a cell membrane from a region of higher water concentration to a region of lower water concentration--water traveled from the relatively diluted polymer solution inside the cell to the more concentrated sugar solution outside the cell. As a result, the volume of the polymer solution inside the membrane was reduced.

With a cell membrane that was now
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