Abstract
The blob model is a well-known scaling theory for polymers in confined environments. In this manuscript, the limitations of the blob model for a flexible polymer confined inside a nano-cylinder are clarified theoretically and using molecular dynamics simulations. In this model, the confined polymer is divided into smaller sections called blobs. The free energy of the confined polymer is accurate under the conditions that (1) the number of monomers inside each blob and (2) total number of the blobs is large enough. In simulations, we consider the opposite limit of extremely narrow nano-channels. Interestingly, the simulation results show that the theory can describe the statics of the confined polymer, even when the above two requirements are not satisfied. However, when simulation parameters are beyond the theoretical limits, the fluctuations in the radius of gyration of the confined polymer have a much stronger dependence on the diameter of the nano-channel than the blob model predicts.
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References
Austin, R.: Nanofluidics: a fork in the nano-road. Nat. Nanotechnol. 2, 79 (2007)
Fu, J., Schoch, R., Stevens, A., Tannenbaum, S., Han, J.: A patterned anisotropic nanofluidic sieving structure for continuous-flow separation of DNA and proteins. Nat. Nanotechnol. 2, 121 (2007)
Marie, R., Pedersen, J., Bauer, D., Rasmussen, K., Yusuf, M., Volpi, E., Flyvbjerg, H., Kristensen, A., Mir, K.: Integrated view of genome structure and sequence of a single DNA molecule in a nanofluidic device. Proc. Natl. Acad. Sci. 110, 4893 (2013)
Ivankin, A., Henley, R., Larkin, J., Carson, S., Toscano, M., Wanunu, M.: Label-free optical detection of biomolecular translocation through nanopore arrays. ACS Nano 8, 10774–10781 (2014)
Plesa, C., van Loo, N., Ketterer, P., Dietz, H., Dekker, C.: Velocity of DNA during translocation through a solid state nanopore. Nano Lett. 15, 732–737 (2015)
Branton, D., Deamer, D., Marziali, A., Bayley, H., Benner, S., Butler, T., Di Ventra, M., Garaj, S., Hibbs, A., Huang, X.: The potential and challenges of nanopore sequencing. Nat. Biotechnol. 26, 1146–1153 (2008)
Wagner, F., Lattanzi, G., Frey, E.: Conformations of confined biopolymers. Phys. Rev. E 75, 050902 (2007)
Zhang, C., Shao, P., van Kan, J., van der Maarel, J.: Macromolecular crowding induced elongation and compaction of single DNA molecules confined in a nanochannel. Proc. Natl. Acad. Sci. 106, 16651 (2009)
Odijk, T.: Scaling theory of DNA confined in nanochannels and nanoslits. Phys. Rev. E 77, 060901 (2008)
Bonthuis, D., Meyer, C., Stein, D., Dekker, C.: Conformation and dynamics of DNA confined in slitlike nanofluidic channels. Phys. Rev. Lett. 101, 108303 (2008)
Chen, Y., Lin, Y., Chang, J., Lin, P.: Dynamics and conformation of semiflexible polymers in strong quasi-1D and-2D confinement. Macromolecules 47, 1199–1205 (2014)
Cui, T., Ding, J., Chen, J.: Dynamics of a self-avoiding polymer chain in slit, tube, and cube confinements. Phys. Rev. E 78, 061802 (2008)
Dai, L., Jones, J., van der Maarel, J., Doyle, P.: A systematic study of DNA conformation in slitlike confinement. Soft Matter 8, 2972–2982 (2012)
Dai, L., Dai, L., Tree, D., van der Maarel, J., Dorfman, K., Doyle, P.: Revisiting blob theory for DNA diffusivity in slitlike confinement. Phys. Rev. Lett. 110, 168105 (2013)
Dimitrov, D., Milchev, A., Binder, K., Klushin, L., Skvortsov, A.: Universal properties of a single polymer chain in slit: scaling versus molecular dynamics simulations. J. Chem. Phys. 128, 234902 (2008)
Nikoofard, N., Hoseinpoor, M., Zahedifar, M.: Accuracy of the blob model for single flexible polymers inside nanoslits that are a few monomer sizes wide. Phys. Rev. E 90, 062603 (2014)
Reccius, C., Mannion, J., Cross, J., Craighead, H.: Compression and free expansion of single DNA molecules in nanochannels. Phys. Rev. Lett. 95, 268101 (2005)
Jun, S., Thirumalai, D., Ha, B.: Compression and stretching of a self-avoiding chain in cylindrical nanopores. Phys. Rev. Lett. 101, 138101 (2008)
Reisner, W., Morton, K., Riehn, R., Wang, Y., Yu, Z., Rosen, M., Sturm, J., Chou, S., Frey, E., Austin, R.: Statics and dynamics of single DNA molecules confined in nanochannels. Phys. Rev. Lett. 94, 196101 (2005)
Reisner, W., Pedersen, J., Austin, R.: DNA confinement in nanochannels: physics and biological applications. Rep. Prog. Phys. 75, 106601 (2012)
Tree, D., Wang, Y., Dorfman, K.: Extension of DNA in a nanochannel as a rod-to-coil transition. Phys. Rev. Lett. 110, 208103 (2013)
Burkhardt, T.: Harmonically confined, semiflexible polymer in a channel: response to a stretching force and spatial distribution of the endpoints. J. Stat. Phys. 145, 1472–1484 (2011)
Fathizadeh, A., Heidari, M., Eslami-Mossallam, B., Ejtehadi, M.: Confinement dynamics of a semiflexible chain inside nano-spheres. J. Chem. Phys. 139, 044912 (2013)
Berndsen, Z., Berndsen, Z., Keller, N., Grimes, S., Jardine, P., Smith, D.: Nonequilibrium dynamics and ultraslow relaxation of confined DNA during viral packaging. Proc. Natl. Acad. Sci. 111, 8345–8350 (2014)
Jie, G., Tang, P., Yang, Y., Chen, J.: Free energy of a long semiflexible polymer confined in a spherical cavity. Soft Matter 10, 4674–4685 (2014)
Rubinstein, M., Colby, R.: Polymers Physics. Oxford University Press, Oxford (2003)
Kim, Y., Kim, K., Kounovsky, K., Chang, R., Jung, G., Jo, K., Schwartz, D.: Nanochannel confinement: DNA stretch approaching full contour length. Lab Chip 11, 1721–1729 (2011)
Matsuoka, T., Kim, B., Huang, J., Douville, N., Thouless, M., Takayama, S.: Nanoscale squeezing in elastomeric nanochannels for single chromatin linearization. Nano Lett. 12, 6480–6484 (2012)
Kim, J., Jeon, C., Jeong, H., Jung, Y., Ha, B.: Elasticity of flexible polymers under cylindrical confinement: appreciating the blob scaling regime in computer simulations. Soft Matter 9, 6142–6150 (2013)
Arnold, A., Bozorgui, B., Frenkel, D., Ha, B., Jun, S.: Unexpected relaxation dynamics of a self-avoiding polymer in cylindrical confinement. J. Chem. Phys. 127, 164903 (2007)
Jung, Y., Jun, S., Ha, B.: Self-avoiding polymer trapped inside a cylindrical pore: flory free energy and unexpected dynamics. Phys. Rev. E 79, 061912 (2009)
Limbach, H., Arnold, A., Mann, B., Holm, C.: ESPResSo–an extensible simulation package for research on soft matter systems. Comput. Phys. Commun. 174, 704–727 (2006)
Humphrey, W., Dalke, A., Schulten, K.: VMD: visual molecular dynamics. Graphics 14, 33–38 (1996)
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Hoseinpoor, S.M., Nikoofard, N. & Zahedifar, M. Accuracy Limits of the Blob Model for a Flexible Polymer Confined Inside a Cylindrical Nano-Channel. J Stat Phys 163, 593–603 (2016). https://doi.org/10.1007/s10955-016-1489-9
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DOI: https://doi.org/10.1007/s10955-016-1489-9