This proposal requests funds for the purchase of equipment necessary to establish a multi-user Laser Tweezers and Laser Scissors center. The development of optical trapping by laser light using single- beam gradient force traps (popularly referred to as optical tweezers) has provided a powerful tool for micromanipulating cells and polymers both in vivo and in vltro. The instrumentation can be used to elucidate qualitative and quantitative properties of organelles or intracellular bacteria inside living cells as well as particles or bacteria attached to the surfaces of living cells. Experiments are also proposed for the use of the Laser Tweezers to measure the force development of beads coated with motor molecules in cell-free systems. The power of the Laser Scissors can be used to make precise surgical cuts inside living cells as well as in isolated polymer systems. Experiments are also proposed to use the Laser Scissors to cut parts of cells and axons that can then be isolated with the Cell Selector microsyringe so that they can be analyzed for different types of mRNA. The Laser Tweezers and Laser Scissors will be mounted on a requested Nikon inverted microscope. This laser center will be administered by experienced investigators and will be available for investigators and their students at the University of Pennsylvania. The instrumentation will be unique on the campus and will permit problems of a fundamental nature to be addressed that would otherwise not be possible. ~ - I
