Single Molecule Polymer Physics Experiments
Single, fluorescently
labeled DNA molecules may be taken as a model system for studying polymer
physics and rheology questions.Polymer
physics concerns the statistical mechanics and hydrodynamics of flexible,
chain like molecules.Rheology concerns
the flow properties of complex fluids and how the macroscopic fluid properties
derive from the microscopic dynamics of dissolved macromolecules. (for
more information see my publications)
(Above) Images of a single ~100 kB
DNA molecule (~40 microns long) tethered to a 1 micron latex bead.The
bead was trapped using optical tweezers and the DNA was labeled with a
fluorescent dye.The DNA was stretched
in a flow (far left) and its entropic relaxation was observed after the
flow was turned off (left to right, 5 second intervals).(see
Perkins, Smith, Chu, Science 264, 819 (1994)).
Schematic of experimental setup:
