Forces of interaction between DNA-grafted colloids: an optical tweezer measurement.
Optical tweezers are employed to measure the forces of interaction between single DNA-grafted colloids. Parameters to be varied are the length of the DNA, the grafting density, and the ion concentration of the surrounding medium. From the measured force-separation dependence an interaction length at a given force is deduced. It shows in the mushroom regime a scaling with the grafting density which levels off for brushes. For the latter the transition from an osmotic to a salted brush can be traced in detail by varying the ion concentration in accordance with mean field theories.
Kegler
K
K
University of Leipzig, Institute of Experimental Physics I, Linnéstrasse 5, D-04103 Leipzig, Germany.
Salomo
M
M
Kremer
F
F
D055592:Biophysical Phenomena; D001703:Biophysics; D003102:Colloids; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes; D052898:Optical Tweezers; D013816:Thermodynamics
D003102:Colloids; D004573:Electrolytes; D004247:DNA