Spring 2012:Vincent Lee Lab 1
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Revision as of 07:32, 13 March 2012 by Vincent Lee (Talk | contribs)
Contents
Objectives
- Familiarization with optical trapping theory and practice.
- Preparing and trapping E Coli to measure flagella strength/speed
Calibrations
- Calibrations done with 0.97µm silica beads
Trap Stiffness
- PSD data taken at ~70mW, ~80mW, and ~90mW
- Stokes drag data taken at 80mW and 70mW
Position
- Position calibration done with beads stuck in 10M Aqueous NaCl
E Coli
The E Coli were genetically modified to stick to the cover glass of the microscope slide and to spin their flagella in only one direction. The intent of the experiment was to measure the force behind velocity of an average E Coli flagellum.
Findings
Issues
- Initially, camera was not fast enough to see the quickly spinning E Coli, need at least a camera of 20FPS
- Flushing the slide proved delicate, ended up working best with very light suction and water feed
- Population density of E Coli sometimes became an issue, really need a maximum of ~15 bacteria per slide, otherwise they really impinge on each other's movement
- Bacteria that stop are annoying
