Protein-Based Computers; March 1995; Scientific American Magazine; by Birge; 6 Page(s)

The world's most advanced supercomputer does not require a single semiconductor chip. The human brain consists of organic molecules that combine to form a highly sophisticated network able to calculate, perceive, manipulate, self-repair, think and feel. Digital computers can certainly perform calculations much faster and more precisely than humans can, but even simple organisms are superior to computers in the other five domains. Computer designers may never be able to make machines having all the faculties of a natural brain, but many of us think we can exploit some special properties of biological molecules--particularly proteins--to build computer components that are smaller, faster and more powerful than any electronic devices on the drawing boards thus far.

The size issue is especially pressing. Since the 1960s the computer industry has been compelled to make the individual components on semiconductor chips smaller and smaller in order to manufacture larger memories and more powerful processors economically. These chips essentially consist of arrays of switches, usually of the kind known as logic gates, that flip between two states--designated as 0 and 1--in response to changes in the electric current passing through them. (Computers typically represent all information in terms of such binary digits, or bits. ) If the trend toward miniaturization continues, the size of a single logic gate will approach the size of molecules by about the year 2030.