Biochip holds millions of vessels

Researchers are putting more of the pieces together to construct full-blown labs-on-a-chip, a possibility that promises inexpensive, hand-held biological, chemical and medical tests similar to the way the computer chip revolutionized electronics.

Researchers from the Swiss Federal Institute of Technology and IBM Research have found a way to make and organize tiny containers that could be used on labs-on-a-chip.

To make the tiny, self-organizing containers, the researchers stamped a pattern of nanometer-size dots of bovine serum albumin and biotin molecules onto glass and treated the surface with a second protein, streptavidin, which connects to biotin. They then added a solution of vesicles that also contained biotin, which bound to the streptavidin to connect one vesical to each dot. Vesicles are tiny containers formed from lipids, the same material that makes up cell walls.

The researchers showed that is possible to assemble within minutes an array of millions of 100-nanometer containers, which each hold only a few millionths of a billionth of a milliliter.

The biocompatible containers will eventually enable labs-on-a-chip to isolate, transport and position water-soluble molecules, according to the researchers. Reactions can take place inside the containers and the small size of the vesicles will allow for tests using extremely small quantities of chemicals for each reaction.

The method could be used to create usable vesical arrays within three to five years, according to the researchers. The work appeared in the November 24, 2003 issue of Angewandte Chemie International Edition.