1
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Zeng L, Capaldi X, Liu Z, Reisner WW. Transient physics in the compression and mixing dynamics of two nanochannel-confined polymer chains. Phys Rev E 2024; 109:024501. [PMID: 38491709 DOI: 10.1103/physreve.109.024501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/16/2024] [Indexed: 03/18/2024]
Abstract
We use molecular dynamics (MD) simulation and nanofluidic experiments to probe the non-equilibrium transient physics of two nanochannel-confined polymers driven against a permeable barrier in a flow field. For chains with a persistence length P smaller than the channel diameter D, both simulation and experiment with dsDNA reveal nonuniform mixing of the two chains, with one chain dominating locally in what we term "aggregates." Aggregates undergo stochastic dynamics, persisting for a limited time, then disappearing and reforming. Whereas aggregate-prone mixing occurs immediately at sufficiently high flow speeds, chains stay segregated at intermediate flow for some time, often attempting to mix multiple times, before suddenly successfully mixing. Observation of successful mixing nucleation events in nanofluidic experiments reveal that they arise through a peculiar "back-propagation" mechanism whereby the upstream chain, closest to the barrier, penetrates and passes through the downstream chain (farthest from the barrier) moving against the flow direction. Simulations suggest that the observed back-propagation nucleation mechanism is favored at intermediate flow speeds and arises from a special configuration where the upstream chain exhibits one or more folds facing the downstream chain, while the downstream chain has an unfolded chain end facing upstream.
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Affiliation(s)
- Lili Zeng
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Xavier Capaldi
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Zezhou Liu
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Walter W Reisner
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
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2
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Rusková R, Račko D. Knot Formation on DNA Pushed Inside Chiral Nanochannels. Polymers (Basel) 2023; 15:4185. [PMID: 37896430 PMCID: PMC10611388 DOI: 10.3390/polym15204185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
We performed coarse-grained molecular dynamics simulations of DNA polymers pushed inside infinite open chiral and achiral channels. We investigated the behavior of the polymer metrics in terms of span, monomer distributions and changes of topological state of the polymer in the channels. We also compared the regime of pushing a polymer inside the infinite channel to the case of polymer compression in finite channels of knot factories investigated in earlier works. We observed that the compression in the open channels affects the polymer metrics to different extents in chiral and achiral channels. We also observed that the chiral channels give rise to the formation of equichiral knots with the same handedness as the handedness of the chiral channels.
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Affiliation(s)
- Renáta Rusková
- Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
| | - Dušan Račko
- Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
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3
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Zeng L, Reisner WW. Mixing and demixing arising from compression of two semiflexible polymer chains in nanochannels. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:88. [PMID: 37755600 DOI: 10.1140/epje/s10189-023-00346-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/03/2023] [Indexed: 09/28/2023]
Abstract
We use molecular dynamics simulation to probe the non-equilibrium physics of two nanochannel-confined semiflexible polymers in a homogeneous flow field. We find that for sufficiently stiff chains the internal organization of the two chains takes the form of interwoven folds and circular coils. This organization can lead to mixing or demixing depending on chain stiffness and flow speed. At low and intermediate flow, the two chains adopt a folded configuration, which favours mixing. At high flow, the two chains adopt a predominantly coiled configuration. The coiled configuration results in demixing when the chains are compressed from an initially demixed condition and mixing when the chains are compressed from an initially mixed condition. We find that the mixing/demixing behaviour is governed by the ratio of the number of folded segments of one chain relative to the other at low flow and by the degree of coiling in both chains at high flow. For decreasing stiffness, the chains start to aggregate locally instead of mixing smoothly at low and intermediate flow. In the limit of completely flexible chains, the two chains either completely segregate at low flow, or adopt a locally demixed configuration consisting of large aggregates of one chain relative to the other that undergo complex stochastic dynamics, diffusing, disintegrating, and reforming at intermediate flow. The transition from complete segregation to the aggregate-dominated configuration occurs when the linear intra-chain ordering breaks down.
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Affiliation(s)
- Lili Zeng
- Department of Physics, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada.
| | - Walter W Reisner
- Department of Physics, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada
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4
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Knot Factories with Helical Geometry Enhance Knotting and Induce Handedness to Knots. Polymers (Basel) 2022; 14:polym14194201. [PMID: 36236148 PMCID: PMC9572405 DOI: 10.3390/polym14194201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/25/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022] Open
Abstract
We performed molecular dynamics simulations of DNA polymer chains confined in helical nano-channels under compression in order to explore the potential of knot-factories with helical geometry to produce knots with a preferred handedness. In our simulations, we explore mutual effect of the confinement strength and compressive forces in a range covering weak, intermediate and strong confinement together with weak and strong compressive forces. The results find that while the common metrics of polymer chain in cylindrical and helical channels are very similar, the DNA in helical channels exhibits greatly different topology in terms of chain knottedness, writhe and handedness of knots. The results show that knots with a preferred chirality in terms of average writhe can be produced by using channels with a chosen handedness.
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5
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Zeng L, Reisner WW. Organized states arising from compression of single semiflexible polymer chains in nanochannels. Phys Rev E 2022; 105:064501. [PMID: 35854522 DOI: 10.1103/physreve.105.064501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
We use molecular dynamics simulation to probe the nonequilibrium physics of single nanochannel-confined semiflexible polymers in a homogeneous flow field. The flow field compresses the polymer against the end of the nanochannel, simulating an experiment of a nanochannel confined chain compressed against a slit barrier. The flow-based compression gives rise to a packing of the chain against the channel end that possesses a striking organization, consisting of interweaving of folds and circular coils. For stiff chains at low flow, we find that the organization is dominated by repeated hairpin folds. For stiff chains at higher flow, we observe that circular coils arise along with the folds, with folding and coiling domains becoming interwoven at the highest flow speeds. Chain organization is retained even when the chain persistence length is on order of the channel width. We show that the global polymer organization, consisting of a number of defined folds and coiled loops, arises from the minimization of the total chain free energy.
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Affiliation(s)
- Lili Zeng
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Walter W Reisner
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
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6
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Rothörl J, Wettermann S, Virnau P, Bhattacharya A. Knot formation of dsDNA pushed inside a nanochannel. Sci Rep 2022; 12:5342. [PMID: 35351953 PMCID: PMC8964721 DOI: 10.1038/s41598-022-09242-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/17/2022] [Indexed: 12/23/2022] Open
Abstract
Recent experiments demonstrated that knots in single molecule dsDNA can be formed by compression in a nanochannel. In this manuscript, we further elucidate the underlying molecular mechanisms by carrying out a compression experiment in silico, where an equilibrated coarse-grained double-stranded DNA confined in a square channel is pushed by a piston. The probability of forming knots is a non-monotonic function of the persistence length and can be enhanced significantly by increasing the piston speed. Under compression knots are abundant and delocalized due to a backfolding mechanism from which chain-spanning loops emerge, while knots are less frequent and only weakly localized in equilibrium. Our in silico study thus provides insights into the formation, origin and control of DNA knots in nanopores.
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Affiliation(s)
- Jan Rothörl
- Institut für Physik, Johannes Gutenberg-Universität, Staudinger Weg 9, 55099, Mainz, Germany
| | - Sarah Wettermann
- Institut für Physik, Johannes Gutenberg-Universität, Staudinger Weg 9, 55099, Mainz, Germany
| | - Peter Virnau
- Institut für Physik, Johannes Gutenberg-Universität, Staudinger Weg 9, 55099, Mainz, Germany.
| | - Aniket Bhattacharya
- Department of Physics, University of Central Florida, Orlando, FL, 32816-2385, USA.
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7
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Chen W, Wei S. Compressive deformations of ring polymers in a confining channel. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.124340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Chen W, Kong X, Wei Q, Chen H, Liu J, Jiang D. Compression and Stretching of Confined Linear and Ring Polymers by Applying Force. Polymers (Basel) 2021; 13:polym13234193. [PMID: 34883696 PMCID: PMC8659573 DOI: 10.3390/polym13234193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
We use Langevin dynamics to study the deformations of linear and ring polymers in different confinements by applying compression and stretching forces on their two sides. Our results show that the compression deformations are the results of an interplay among of polymer rigidity, degree of confinement, and force applied. When the applied force is beyond the threshold required for the buckling transition, the semiflexible chain under the strong confinement firstly buckles; then comes helical deformation. However, under the same force loading, the semiflexible chain under the weaker confinement exhibits buckling instability and shrinks from the folded ends/sides until it becomes three-folded structures. This happens because the strong confinement not only strongly reduces the buckling wavelength, but also increases the critical buckling force threshold. For the weakly confined polymers, in compression process, the flexible linear polymer collapses into condensed states under a small external force, whereas the ring polymer only shows slight shrinkage, due to the excluded volume interactions of two strands in the crowded states. These results are essential for understanding the deformations of the ring biomacromolecules and polymer chains in mechanical compression or driven transport.
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Affiliation(s)
- Wenduo Chen
- School of Materials, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; (Q.W.); (H.C.); (J.L.); (D.J.)
- School of Materials, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen 518107, China
- Correspondence:
| | - Xiangxin Kong
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China;
| | - Qianqian Wei
- School of Materials, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; (Q.W.); (H.C.); (J.L.); (D.J.)
- School of Materials, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Huaiyu Chen
- School of Materials, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; (Q.W.); (H.C.); (J.L.); (D.J.)
- School of Materials, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Jiayin Liu
- School of Materials, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; (Q.W.); (H.C.); (J.L.); (D.J.)
- School of Materials, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Dazhi Jiang
- School of Materials, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; (Q.W.); (H.C.); (J.L.); (D.J.)
- School of Materials, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen 518107, China
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9
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Jung Y, Ha BY. Confinement induces helical organization of chromosome-like polymers. Sci Rep 2019; 9:869. [PMID: 30696884 PMCID: PMC6351567 DOI: 10.1038/s41598-018-37261-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/03/2018] [Indexed: 11/24/2022] Open
Abstract
Helical organization is commonly observed for a variety of biopolymers. Here we study the helical organization of two types of biopolymers, i.e., DNA-like semiflexible and bottle-brush polymers, in a cell-like confined space. A bottle-brush polymer consists of a backbone and side chains emanating from the backbone, resembling a supercoiled bacterial chromosome. Using computer simulations, we calculate 'writhe' distributions of confined biopolymers for a wide range of parameters. Our effort clarifies the conditions under which biopolymers are helically organized. While helical organization is not easily realized for DNA-like biomolecules, cylindrical confinement can induce spiral patterns in a bottle brush, similarly to what was observed with bacterial chromosomes. They also suggest that ring-shape bottle brushes have a stronger tendency for helical organization. We discuss how our results can be used to interpret chromosome experiments. For instance, they suggest that experimental resolution has unexpected consequences on writhe measurements (e.g., narrowing of the writhe distribution and kinetic separation of opposite helical states).
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Affiliation(s)
- Youngkyun Jung
- Supercomputing Center, Korea Institute of Science and Technology Information, Daejeon, 34141, Korea.
| | - Bae-Yeun Ha
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
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10
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Pereira MCF, Brackley CA, Lintuvuori JS, Marenduzzo D, Orlandini E. Entropic elasticity and dynamics of the bacterial chromosome: A simulation study. J Chem Phys 2018; 147:044908. [PMID: 28764377 DOI: 10.1063/1.4995992] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We study the compression and extension dynamics of a DNA-like polymer interacting with non-DNA binding and DNA-binding proteins, by means of computer simulations. The geometry we consider is inspired by recent experiments probing the compressional elasticity of the bacterial nucleoid (DNA plus associated proteins), where DNA is confined into a cylindrical container and subjected to the action of a "piston"-a spherical bead to which an external force is applied. We quantify the effect of steric interactions (excluded volume) on the force-extension curves as the polymer is compressed. We find that non-DNA-binding proteins, even at low densities, exert an osmotic force which can be a lot larger than the entropic force exerted by the compressed DNA. The trends we observe are qualitatively robust with respect to changes in protein sizes and are similar for neutral and charged proteins (and DNA). We also quantify the dynamics of DNA expansion following removal of the "piston": while the expansion is well fitted by power laws, the apparent exponent depends on protein concentration and protein-DNA interaction in a significant way. We further highlight an interesting kinetic process which we observe during the expansion of DNA interacting with DNA-binding proteins when the interaction strength is intermediate: the proteins bind while the DNA is packaged by the compression force, but they "pop-off" one-by-one as the force is removed, leading to a slow unzipping kinetics. Finally, we quantify the importance of supercoiling, which is an important feature of bacterial DNA in vivo.
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Affiliation(s)
- M C F Pereira
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - C A Brackley
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - J S Lintuvuori
- Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Universite Paris-Saclay, 91405 Orsay Cedex, France
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - E Orlandini
- Dipartimento di Fisica e Astronomia and Sezione INFN, Università di Padova, Via Marzolo 8, Padova, 35131 PD, Italy
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11
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Sakaue T. Compressing a confined DNA: from nano-channel to nano-cavity. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:244004. [PMID: 29726839 DOI: 10.1088/1361-648x/aac286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We analyze the behavior of a semiflexible polymer confined in nanochannel under compression in axial direction. Key to our discussion is the identification of two length scales; the correlation length ξ of concentration fluctuation and what we call the segregation length [Formula: see text]. These length scales, while degenerate in uncompressed state in nanochannel, generally split as [Formula: see text] upon compression, and the way they compete with the system size during the compression determines the crossover from quasi-1D nanochannel to quasi-0D nanocavity behaviors. For a flexible polymer, the story becomes very simple, which corresponds to a special limit of our description, but a much richer behavior is expected for a semiflexible polymer relevant to DNA in confined spaces. We also briefly discuss the dynamical properties of the compressed polymer.
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Affiliation(s)
- Takahiro Sakaue
- Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan. PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama, 332-0012, Japan
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12
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Bernier S, Huang A, Reisner W, Bhattacharya A. Evolution of Nested Folding States in Compression of a Strongly Confined Semiflexible Chain. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02748] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Simon Bernier
- Department of Physics, McGill University, 3600 rue university, Montreal, Quebec H3A 2T8, Canada
| | - Aiqun Huang
- Department of Physics, University of Central Florida, 4111 Libra Drive, Orlando, Florida 32816, United States
| | - Walter Reisner
- Department of Physics, McGill University, 3600 rue university, Montreal, Quebec H3A 2T8, Canada
| | - Aniket Bhattacharya
- Department of Physics, University of Central Florida, 4111 Libra Drive, Orlando, Florida 32816, United States
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13
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Amin S, Khorshid A, Zeng L, Zimny P, Reisner W. A nanofluidic knot factory based on compression of single DNA in nanochannels. Nat Commun 2018; 9:1506. [PMID: 29666466 PMCID: PMC5904144 DOI: 10.1038/s41467-018-03901-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 03/21/2018] [Indexed: 11/09/2022] Open
Abstract
Knots form when polymers self-entangle, a process enhanced by compaction with important implications in biological and artificial systems involving chain confinement. In particular, new experimental tools are needed to assess the impact of multiple variables influencing knotting probability. Here, we introduce a nanofluidic knot factory for efficient knot formation and detection. Knots are produced during hydrodynamic compression of single DNA molecules against barriers in a nanochannel; subsequent extension of the chain enables direct assessment of the number of independently evolving knots. Knotting probability increases with chain compression as well as with waiting time in the compressed state. Using a free energy derived from scaling arguments, we develop a knot-formation model that can quantify the effect of interactions and the breakdown of Poisson statistics at high compression. Our model suggests that highly compressed knotted states are stabilized by a decreased free energy as knotted contour contributes a lower self-exclusion derived free energy.
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Affiliation(s)
- Susan Amin
- Department of Physics, McGill University, 3600 rue université, Montréal, QC, H3A 2T8, Canada
| | - Ahmed Khorshid
- Department of Physics, McGill University, 3600 rue université, Montréal, QC, H3A 2T8, Canada
| | - Lili Zeng
- Department of Physics, McGill University, 3600 rue université, Montréal, QC, H3A 2T8, Canada
| | - Philip Zimny
- Department of Biomedical Engineering, McGill University, 3775 rue université, Montréal, QC, H3A 2B4, Canada
| | - Walter Reisner
- Department of Physics, McGill University, 3600 rue université, Montréal, QC, H3A 2T8, Canada.
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14
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Reifenberger JG, Cao H, Dorfman KD. Odijk excluded volume interactions during the unfolding of DNA confined in a nanochannel. Macromolecules 2018; 51:1172-1180. [PMID: 29479117 PMCID: PMC5823525 DOI: 10.1021/acs.macromol.7b02466] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report experimental data on the unfolding of human and E. coli genomic DNA molecules shortly after injection into a 45 nm nanochannel. The unfolding dynamics are deterministic, consistent with previous experiments and modeling in larger channels, and do not depend on the biological origin of the DNA. The measured entropic unfolding force per friction per unit contour length agrees with that predicted by combining the Odijk excluded volume with numerical calculations of the Kirkwood diffusivity of confined DNA. The time scale emerging from our analysis has implications for genome mapping in nanochannels, especially as the technology moves towards longer DNA, by setting a lower bound for the delay time before making a measurement.
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Affiliation(s)
| | - Han Cao
- BioNano Genomics Inc., 9640 Towne Centre Drive, Suite 100, San Diego, CA 92121
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota – Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
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15
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Qi Y, Zeng L, Khorshid A, Hill RJ, Reisner WW. Compression of Nanoslit Confined Polymer Solutions. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b01894] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yue Qi
- Department
of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Lili Zeng
- Department
of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Ahmed Khorshid
- Department
of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
| | - Reghan J. Hill
- Department
of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 0C5, Canada
| | - Walter W. Reisner
- Department
of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada
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16
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Zhou J, Wang Y, Menard LD, Panyukov S, Rubinstein M, Ramsey JM. Enhanced nanochannel translocation and localization of genomic DNA molecules using three-dimensional nanofunnels. Nat Commun 2017; 8:807. [PMID: 28993619 PMCID: PMC5634460 DOI: 10.1038/s41467-017-00951-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 08/08/2017] [Indexed: 12/13/2022] Open
Abstract
The ability to precisely control the transport of single DNA molecules through a nanoscale channel is critical to DNA sequencing and mapping technologies that are currently under development. Here we show how the electrokinetically driven introduction of DNA molecules into a nanochannel is facilitated by incorporating a three-dimensional nanofunnel at the nanochannel entrance. Individual DNA molecules are imaged as they attempt to overcome the entropic barrier to nanochannel entry through nanofunnels with various shapes. Theoretical modeling of this behavior reveals the pushing and pulling forces that result in up to a 30-fold reduction in the threshold electric field needed to initiate nanochannel entry. In some cases, DNA molecules are stably trapped and axially positioned within a nanofunnel at sub-threshold electric field strengths, suggesting the utility of nanofunnels as force spectroscopy tools. These applications illustrate the benefit of finely tuning nanoscale conduit geometries, which can be designed using the theoretical model developed here.Forcing a DNA molecule into a nanoscale channel requires overcoming the free energy barrier associated with confinement. Here, the authors show that DNA injected through a funnel-shaped entrance more efficiently enters the nanochannel, thanks to facilitating forces generated by the nanofunnel geometry.
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Affiliation(s)
- Jinsheng Zhou
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Yanqian Wang
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Laurent D Menard
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Sergey Panyukov
- PN Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117924, Russia
| | - Michael Rubinstein
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
- Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - J Michael Ramsey
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, NC, 27599, USA.
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17
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Dai L, Jones JJ, Klotz AR, Levy S, Doyle PS. Nanoconfinement greatly speeds up the nucleation and the annealing in single-DNA collapse. SOFT MATTER 2017; 13:6363-6371. [PMID: 28868564 DOI: 10.1039/c7sm01249g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Manipulating and measuring single-molecule dynamics and reactions in nanofluidics is a rapidly growing field with broad applications in developing new biotechnologies, understanding nanoconfinement effects in vivo, and exploring new phenomena in confinement. In this work, we investigate the kinetics of DNA collapse in nanoslits using single T4-DNA (165.6 kbp) and λ-DNA (48.5 kbp), with particular focus on the measurement of the nucleation and annealing times. Fixing the ethanol concentration at 35% and varying the slit height from 2000 to 31 nm, the nucleation time dramatically decreases from more than 1 hour to a few minutes or less. The increased collapsed rate results from the larger free energy experienced by coiled DNA in confinement relative to compacted DNA. Our results also shed light on other conformational transitions in confinement, such as protein folding.
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Affiliation(s)
- Liang Dai
- BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore 117543, Singapore.
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Hayase Y, Sakaue T, Nakanishi H. Compressive response and helix formation of a semiflexible polymer confined in a nanochannel. Phys Rev E 2017; 95:052502. [PMID: 28618466 DOI: 10.1103/physreve.95.052502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 06/07/2023]
Abstract
Configurations of a single semiflexible polymer is studied when it is pushed into a nanochannel in the case where the polymer persistence length l_{p} is much longer than the channel diameter D:l_{p}/D≫1. Using numerical simulations, we show that the polymer undergoes a sequence of recurring structural transitions upon longitudinal compression: random deflection along the channel, a helix going around the channel wall, double-fold random deflection, double-fold helix, etc. We find that the helix transition can be understood as buckling of deflection segments, and the initial helix formation takes place at very small compression with no appreciable weak compression regime of the random deflection polymer.
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Affiliation(s)
- Yumino Hayase
- Department of Mathematical and Live Sciences, Hiroshima University, Hiroshima 739-8526, Japan
| | - Takahiro Sakaue
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
- JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Hiizu Nakanishi
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
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Saito T, Sakaue T. Complementary mode analyses between sub- and superdiffusion. Phys Rev E 2017; 95:042143. [PMID: 28505743 DOI: 10.1103/physreve.95.042143] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Indexed: 06/07/2023]
Abstract
Several subdiffusive stochastic processes in nature, e.g., the motion of a tagged monomer in polymers, the height fluctuation of interfaces, particle dynamics in single-file diffusion, etc., can be described rigorously or approximately by the superposition of various modes whose relaxation times are broadly distributed. In this paper, we propose a mode analysis generating superdiffusion, which is paired with or complementary to subdiffusion. The key point in our discussion lies in the identification of a pair of conjugated variables, which undergo sub- and superdiffusion, respectively. We provide a simple interpretation for the sub- and superdiffusion duality for these variables using the language of polymer physics. The analysis also suggests the usefulness of looking at the force fluctuation in experiments, where a polymer is driven by a constant velocity.
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Affiliation(s)
- Takuya Saito
- Earthquake Research Institute, University of Tokyo, Tokyo 113-0032, Japan
| | - Takahiro Sakaue
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Huang A, Reisner W, Bhattacharya A. Dynamics of DNA Squeezed Inside a Nanochannel via a Sliding Gasket. Polymers (Basel) 2016; 8:E352. [PMID: 30974628 PMCID: PMC6432381 DOI: 10.3390/polym8100352] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 11/16/2022] Open
Abstract
We use Brownian dynamics (BD) simulation of a coarse-grained (CG) bead-spring model of DNA to study the nonequilibrim dynamics of a single DNA molecule confined inside a rectangular nanochannel being squeezed with a sliding gasket piston or "nanodozer". From our simulations we extract the nonequilibrim density profile c ( x , t ) of the squeezed molecule along the channel axis (x-coordinate) and then analyze the non-equilibrium profile using a recently introduced phenomenological Nonlinear Partial Differential Equation (NPDE) model. Since the NPDE approach also fits the experimental results well and is numerically efficient to implement, the combined BD + NPDE methods can be a powerful approach to analyze details of the confined molecular dynamics. In particular, the overall excellent agreement between the two complementary sets of data provides a strategy for carrying out large scale simulation on semi-flexible biopolymers in confinement at biologically relevant length scales.
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Affiliation(s)
- Aiqun Huang
- University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA.
| | - Walter Reisner
- McGill University, 845 Rue Sherbrooke O, Montréal, QC H3A 0G4, Canada.
| | - Aniket Bhattacharya
- University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA.
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Jain A, Sheats J, Reifenberger JG, Cao H, Dorfman KD. Modeling the relaxation of internal DNA segments during genome mapping in nanochannels. BIOMICROFLUIDICS 2016; 10:054117. [PMID: 27795749 PMCID: PMC5065570 DOI: 10.1063/1.4964927] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 10/04/2016] [Indexed: 06/01/2023]
Abstract
We have developed a multi-scale model describing the dynamics of internal segments of DNA in nanochannels used for genome mapping. In addition to the channel geometry, the model takes as its inputs the DNA properties in free solution (persistence length, effective width, molecular weight, and segmental hydrodynamic radius) and buffer properties (temperature and viscosity). Using pruned-enriched Rosenbluth simulations of a discrete wormlike chain model with circa 10 base pair resolution and a numerical solution for the hydrodynamic interactions in confinement, we convert these experimentally available inputs into the necessary parameters for a one-dimensional, Rouse-like model of the confined chain. The resulting coarse-grained model resolves the DNA at a length scale of approximately 6 kilobase pairs in the absence of any global hairpin folds, and is readily studied using a normal-mode analysis or Brownian dynamics simulations. The Rouse-like model successfully reproduces both the trends and order of magnitude of the relaxation time of the distance between labeled segments of DNA obtained in experiments. The model also provides insights that are not readily accessible from experiments, such as the role of the molecular weight of the DNA and location of the labeled segments that impact the statistical models used to construct genome maps from data acquired in nanochannels. The multi-scale approach used here, while focused towards a technologically relevant scenario, is readily adapted to other channel sizes and polymers.
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Affiliation(s)
- Aashish Jain
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities , 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Julian Sheats
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities , 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | | | - Han Cao
- BioNano Genomics , 9640 Towne Centre Drive, Suite 100, San Diego, California 92121, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities , 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
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