Unlike the other technologies highlighted in this issue, optical trapping systems are not typically purchased off-the-shelf. Rather, they are specially built to custom specifications, often at considerable expense.
Henry Shuman, a research associate professor of physiology at the University of Pennsylvania, built one such system over the course of a few months in 2002. With two graduate students he assembled an optical trapping apparatus comprising a microscope body, two lasers, two force sensors, a position sensor, total internal reflection fluorescence (TIRF) capabilities, and a CCD camera. He estimates that it cost in the neighborhood of $250,000.
In collaboration with Yale Goldman and Erika Holzbaur, both also at the University of Pennsylvania, Shuman uses the system to study the biophysics of molecular motors (myosin and dynein, respectively). He also has his own research projects, such as just-published research on the force needed to separate an integrin receptor...