Entropic Colloidal Interactions in Concentrated DNA Solutions
- Department of Physics and Astronomy, University of Pennsylvania, 209 S. 33rd Street, Philadelphia, Pennsylvania 19104 (United States)
We explore the entropic interactions between a pair of micron-sized colloidal spheres in DNA solutions. By confining the particles in a line-scanned optical tweezer, we directly measured the functional form of the interaction potential with sub-k{sub B}T resolution in samples where the spheres and the polymer coils were of comparable size. The potential is well described by the Asakura-Oosawa depletion model even in the semidilute regime where DNA coils overlap strongly. Its range and depth increase with increasing concentration in a manner consistent with a crossover from a dilute solution of Gaussian coils to the weakly fluctuating semidilute regime dominated by two-point collisions which is unique to semiflexible polymers. {copyright} {ital 1998} {ital The American Physical Society }
- OSTI ID:
- 663754
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 18 Vol. 81; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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