CISMM

We announce the 2009 Carolina Workshop on Force Measurement and Manipulation in Biological Microscopy to be held May 12-15, 2009.  Come use magnetic tweezers, laser tweezers and atomic force microscopy on live cells, DNA and blood clots.  Registration will open on November 15, 2008.  Contact Cassandra Houston for more information or go here for a brief description.

Our new website is available to the world as of Oct. 27, 2008.

Movie

A fanciful view inside a cell intended to show the concept of the 3DFM. It starts with a view of several microtubules and follows the motion of a bead along one of them. As it zooms in, we can see a representation of a kinesin walking its way along the microtubule, carrying the bead. Using the 3DFM, we hope to be able to track, stall, and measure the forces on kinesin and other motor proteins as they perform their duties within living cells.

Ming Ouh-young at UNC designed and built a haptic feedback system to simulate the interaction of a drug molecule with its receptor site in a protein. (Brooks, Ouh-Young et al. 1990; Ouh-young 1990) This system, called the Docker, computed the force and torque between the drug and protein due to electrostatic charges and inter-atomic collisions.  These forces were presented to a chemist, pulling the drug towards local energy minima. This task is very similar to that of other “lock and key” applications where a scientist moves one object and senses collisions with other objects in the environment The system presented the force and torque vectors both visually and using haptic feedback. Experiment showed that chemists could perform the rigid-body positioning task required to determine the lowest-energy configuration of the drug up to twice as quickly with haptic feedback turned on compared to using the visual-only representations. (Ouhyoung 1990) Scientists also reported that they felt like they had a better understanding of how the drug fit into the receptor site when they were able to feel the forces.
The Docker application, like other path-planning applications, required the presentation of both force and torque to the user. Because the drug molecule was not a point probe, different portions of it could collide with the protein at the same time. Extricating the drug from a collision sometimes required both translation and twisting. If a chemist were provided with only force (translation) information and no torque (twist) information, they could be led to move the drug in an improper direction.