The scaling of the average gyration radius of polymers as a function of their length can be experimentally determined from ensemble measurements, such as light scattering, and agrees with analytical estimates. Ensemble techniques, yet, do not give access to the full probability distributions. Single molecule techniques, instead, can deliver information on both average quantities and distribution functions. Here we exploit the high resolution of atomic force microscopy over long DNA molecules adsorbed on a surface to measure the average end-to-end distance as a function of the DNA length, and its full distribution function. We find that all the scaling exponents are close to the predicted 3D values (nu=0.589 +/- 0.006 and delta=2.58 +/- 0.77). These results suggest that the adsorption process is akin to a geometric projection from 3D to 2D, known to preserve the scaling properties of fractal objects of dimension d(f)< 2.

Scaling exponents and probability distributions of DNA end-to-end distance / Valle, F; Favre, M; De Los Rios, P; Rosa, Angelo; Dietler, G.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 95:15(2005), pp. 1-4. [10.1103/PhysRevLett.95.158105]

Scaling exponents and probability distributions of DNA end-to-end distance

Rosa, Angelo;
2005-01-01

Abstract

The scaling of the average gyration radius of polymers as a function of their length can be experimentally determined from ensemble measurements, such as light scattering, and agrees with analytical estimates. Ensemble techniques, yet, do not give access to the full probability distributions. Single molecule techniques, instead, can deliver information on both average quantities and distribution functions. Here we exploit the high resolution of atomic force microscopy over long DNA molecules adsorbed on a surface to measure the average end-to-end distance as a function of the DNA length, and its full distribution function. We find that all the scaling exponents are close to the predicted 3D values (nu=0.589 +/- 0.006 and delta=2.58 +/- 0.77). These results suggest that the adsorption process is akin to a geometric projection from 3D to 2D, known to preserve the scaling properties of fractal objects of dimension d(f)< 2.
2005
95
15
1
4
158105
https://doi.org/10.1103/PhysRevLett.95.158105
https://arxiv.org/abs/cond-mat/0503577v1
Valle, F; Favre, M; De Los Rios, P; Rosa, Angelo; Dietler, G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/17311
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