CHICAGO – It's the size of a red blood cell, but it's much, much simpler: it's an artificial cell, created in a laboratory, measuring ten thousandths of a millimeter. One day, experts say, cells of this type could be used, once injected into the body, to make drugs to cure diseases. For now it is only a model, presented at the annual meeting of the American Society for Advancement of Science underway in Chicago. «The cell – said Christine Keating professor of chemistry at Pennsylvania State in Philadelphia – is a very well organized structure and this organization is essential for its functioning. But we still don't know how it's created." To understand it, therefore, we must start from a basic model, a pseudo-cell built with simple molecules. Normally a cell is composed of a membrane and a cytoplasm that fills it: in this cytoplasm there are macromolecules of various types and organelles, such as mitochondria, which are used for its functioning.
A PROTOTYPE – To build the artificial prototype, the researchers used freeze-dried lipid substances and put them in a water solution containing two polymers, Peg (polyethylene glycol) and dextran (a sugar polymer). The lipids are organized in vesicles which are filled with the two substances. The curious thing, however, is that the two substances are located in two distinct parts of the vesicle, somewhat as happens for the molecules contained in "real" cells where certain reactions take place in specific areas of the cytoplasm. Researchers therefore think that certain cellular processes can be controlled precisely by intervening on the position of the molecules in the cytoplasm. As? Using osmotic forces, heating, cooling.
«MINIMUM» FORMS OF LIFE – The road has just begun (other researchers have already studied the insertion of genes into lipid vesicles, they have transplanted the nucleus of a microorganism into the cell of another, they have created an artificial chromosome) and this research has the goal of creating new types of therapy in the future. Different from the classic ones that involve administering a drug to a patient several times a day. With artificial cells one could think of manufacturing drugs directly in the organism, perhaps by exploiting and modifying substances already present in the organism itself.
Adriana Bazzi
February 15, 2009
