Biosensor chip held in a scientist's gloved hand. This is a surface plasmon resonance (SPR) sensor chip used in proteomics research. Proteomics is the study of the structure and function of all proteins in the body. The chip comprises a square of gold film with microscopic grooves on its surface. Biomolecules (such as proteins) can bind to the film, causing changes in the way it reflects light. The tiny grooves guide aqueous solutions to predetermined places on the foil, where different molecules can interact. Studying changes in light reflectance can provide infor- mation about the interactions of the biomolecules.