Building artificial cells from scratch.

Scientists have created artificial ceils that can live and produce proteins as their natural counterparts do, but can't replicate. Besides providing a new tool for studying the biochemical processes that take place inside real cells, these synthetic structures could be enlisted to churn out pharmaceuticals, says Albert Libchaber of Rockefeller University in New York. This advance also brings researchers closer to creating entirely synthetic organisms with artificial chromosomes, he says.

Libchaber and his colleague Vincent Noireaux built their artificial cells using simple starting materials. First, they bought Escherichia coli extract, a genefree, bacteria-derived product that contains the cellular machinery for translating genes into proteins. Next, they added that water-based extract and a few test genes to an oily mixture containing phospholipids--the material that makes up cell membranes. The extract quickly formed into microdroplets, which became encapsulated by phospholipids. The researchers then added a second phospholipid, creating a cell-like double-layered membrane.

One of the test genes encodes a green fluorescent protein, so a green glow let the researchers know that the vesicles were working as planned. The second test gene encodes a protein that forms into membrane-based pores, which enable cells to take up nutrients. Without such pores, the cells stopped producing the fluorescent protein within hours, but with the pores, fluorescence continued for 4, days. The researchers describe their synthetic assemblies in the Dec. 21, 2004 Proceedings of the National Academy of Sciences.