Diffusion of Single Star-Branched Dendrimer-like DNA

Freedman, Katherine O.; Lee, Janet; Li, Yougen; Luo, Dan; Skobeleva, V. B.; Ke, Pu Chun

doi:10.1021/jp0444924

Cited by 33 publications

(37 citation statements)

References 26 publications

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“…In particular, the conformation and relaxation of large polymer chains [62,63], as well as interaction with other chains [64], have been investigated in great detail by single-molecule techniques. Further, as cyclic and star-branched DNA are relatively easily obtainable, topology eff ects on polymer dynamics have also been investigated [65,66]. Th e study of large DNA is facilitated by its size-a fully labeled DNA helix is easily imaged by fl uorescence microscopy and changes in position and shape can be easily and precisely followed.…”

Section: Structure/conformation and Physics Of Non-conjugated Polymersmentioning

confidence: 99%

Conformation and physics of polymer chains: a single-molecule perspective

Vácha

Habuchi

2010

NPG Asia Mater

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N anotechnology has been one of the driving forces of science and technology over the past 20 years. Scaling down the size of an object to nanometer dimensions can result in dramatic changes to its physical properties. With recent progress in the nanoscience and nanotechnology of polymeric materials, new methods are now required for the characterization of polymer structures and properties. Despite the great success of electron microscopy and scanning probe microscope techniques, there remains a need for a non-invasive method that could provide information not only on the structure but also on the physical phenomena occurring on the nanoscale level. One method that has recently emerged as an excellent tool for nanoscale characterization is single-molecule optical detection and spectroscopy. Single-molecule spectroscopy relies on the detection and measurement of the fl uorescence signal and spectra from single isolated molecules or polymer chains (Figure 1). Th ese can either be immobilized in a solid matrix or be diff using in a solution or melt. In all cases, the concentration of the emitting molecules must be suffi ciently low to ensure that the spatial separation between individual molecules is larger than the optical resolution of the setup, typically on the order of micrometers. As the fl uorescence signal from a molecule is strongly infl uenced by the nanoscale environment, measuring many molecules one by one provides the distribution of physical properties of the respective nano-environments. Moreover, monitoring a molecule over a period of time reveals dynamic changes in its environment. Th ese static and dynamic heterogeneities of nanoscale properties are averaged and hidden in the usual ensemble experiments. Th e strength of fl uorescence detection is in its sensitivity and low background level -emissions of just a few hundred photons per second can be readily detected. Th e technique also off ers remarkable dynamic range, from sub-nanosecond timescales to seconds and longer, and is non-invasive, making it possible to detect emissions from molecules buried deep in a sample.Single-molecule spectroscopy has evolved since the beginning of the 1990s from low-temperature, high-resolution optical spectroscopic

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Section: Structure/conformation and Physics Of Non-conjugated Polymersmentioning

confidence: 99%

Conformation and physics of polymer chains: a single-molecule perspective

Vácha

Habuchi

2010

NPG Asia Mater

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“…Our study can also be applied to the general case of loading hydrophobic molecules onto branched polymers, such as encapsulating molecules inside a dendrimer for cell trafficking [31,32] and gene delivery [33]. Another extension from this research lies in our fundamental understanding of the diffusion and reptation of nonlinear polymers [34,35].…”

Section: Resultsmentioning

confidence: 94%

Single-Molecule Dendrimer-Hydrocarbon Interaction

Pasupathy¹,

Suek²,

Lyons³

et al. 2009

TONANOJ

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Abstract:We report our single-molecule fluorescence microscopy and molecular dynamics simulation studies on the interaction of poly(amidoamine) dendrimer and squalane hydrocarbon in aqueous solution. Our spectrophotometry measurements indicate that this interaction increases with the pH of the solvent. Our simulations show that squalane resides primarily on the perimeter of the dendrimer at low to neutral pH, but becomes encapsulated by the dendrimer at high pH. Using single-molecule fluorescence microscopy, we have identified that the binding between PAMAM and squalane is reversible. At a pH value of 8, the approaching, binding, and characteristic times of a single fluorescently-labeled dendrimer to squalane are 0.5 s, 7.5 s, and 0.5 s, respectively. Both our spectrophotometry measurements and simulations show that the interaction between PAMAM and squalane is stronger for lower generation dendrimers. This study facilitates our understanding of using dendritic and hyperbranched polymers for gas hydrate prevention in the petroleum industry.

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“…103 SMforce spectroscopy has also been used to determine persistence lengths of highly branched cylindrical PNIPAM brushes. 104 Studies of the diffusion of branched DNA in dilute and concentrated solutions, as well as electrophoretic mobility, have revealed remarkable differences from the mobility of linear chains. [104][105][106] Overall, single polymer techniques represent a powerful approach to probing the non-equilibrium dynamics of long-chain macromolecules, especially in entangled polymer solutions.…”

Section: Perspectivementioning

confidence: 99%

“…104 Studies of the diffusion of branched DNA in dilute and concentrated solutions, as well as electrophoretic mobility, have revealed remarkable differences from the mobility of linear chains. [104][105][106] Overall, single polymer techniques represent a powerful approach to probing the non-equilibrium dynamics of long-chain macromolecules, especially in entangled polymer solutions. 107,108 Combined with bulk-level analysis, single polymer methods are poised to fundamentally transform our understanding of polymer physics for ''real'' polymer systems in the near future.…”

Section: Perspectivementioning

confidence: 99%

New directions in single polymer dynamics

Marciel

Schroeder

2013

J Polym Sci B Polym Phys

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Single polymer techniques are a powerful set of molecular-level tools that enable the direct observation of polymer chain dynamics under highly non-equilibrium conditions. In this way, single polymer methods have been used to uncover fundamentally new information regarding the static and dynamic properties of polymeric materials. However, to achieve the full potential of these new methods, single polymer techniques must be further advanced to enable the study of polymers with complex architectures, heterogeneous chemistries, flexible backbones, and intermolecular interactions in entangled solutions, which reaches far beyond the current state-of-the-art. In this article, we explore recent developments in the area of single polymer physics, including single molecule force spectroscopy and fluorescence microscopy, and we further highlight exciting new directions in the field. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 556-566 KEYWORDS: biopolymer; fluorescence; imaging; rheology; single molecule; single polymer INTRODUCTION Long chain macromolecules play an indispensable role in modern society. Synthetic polymers are used in a wide array of industrial applications, whereas natural polymers facilitate fundamental life processes. The molecular properties of polymer chains ultimately determine the emergent bulk properties of polymeric materials. In particular, the intrinsic chemical and physical properties of polymers, in conjunction with processing conditions, give rise to polymeric materials with desired function. For many years, bulk characterization techniques such as rheometry and light scattering have been used to infer polymer orientation, conformation, and microstructure at equilibrium and during non-equilibrium processing. Recently, single molecule techniques have enabled the direct observation of polymer chains in far-from-equilibrium conditions, thereby providing a window into the molecular structure and behavior of single polymers. In this way, single polymer studies have the potential to reveal fundamentally new information regarding the processing properties and static and dynamic morphology of polymeric materials. However, to achieve the full potential and promise of single molecule techniques, these new methods must be brought to bear on polymers with complex architectures and heterogeneous chemistries, reaching far beyond the current state-of-the-art. In this article, we explore recent advances in single polymer methods and highlight promising new directions in the field.

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Diffusion of Single Star-Branched Dendrimer-like DNA

Cited by 33 publications

References 26 publications

Conformation and physics of polymer chains: a single-molecule perspective

Conformation and physics of polymer chains: a single-molecule perspective

Single-Molecule Dendrimer-Hydrocarbon Interaction

New directions in single polymer dynamics

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