Many drugs used to treat diseases function by communicating with proteins located in the outer walls of our cells that in turn communicate instructions to the cell itself. Studying these proteins, however, is difficult because isolating them usually impairs their functioning. A method of study using lasers, however, may make the process easier. "Their process is called back-scattering interferometry (B.S.I.). The sample is deposited into a microscopic liquid-filled chamber made of glass and is then illuminated by a laser. Light reflected from it forms an interference pattern that can be captured by a camera."