Proteomic studies in microgravity are crucial to understanding the health effects of spaceflight on astronauts. Unfortunately, existing tools for measuring protein, antibody, and enzyme expression are limited to earth-borne laboratories due to their complexity and size. This proposal offers a novel technology that provides a palm-top platform suitable for real-time experiments on the Space Shuttle or International Space Station. The technology uses nanoelectronic transistors coupled to antibody bioprobes to provide a label-free "direct detection" system that is rapid and easy to use with minimal skill. The system is completely self-contained, including all reagents and waste products, and operated from a PDA-style handheld computer. Phase I will demonstrate the detection concept and Phase II will deliver prototype units for testing.