Persistence length of DNA molecules confined in nanochannels

Peter Cifra; Zuzana Benková; Tomáš Bleha

doi:10.1039/b923598a

Influence of Nanochannel Inlet Structure Upon DNA Capture Ratio

Volume 11: Nano and Micro Materials, Devices and Systems; Microsystems Integration ◽

10.1115/imece2011-64490 ◽

2011 ◽

Author(s):

Jiahao Wu ◽

Hong Wang ◽

Jinsoo Kim ◽

Freddy Murphy ◽

Steven A. Soper ◽

...

Keyword(s):

Real Time ◽

Persistence Length ◽

Contour Length ◽

Dna Molecules ◽

Channel Diameter ◽

Dna Molecule ◽

Capture Ratio ◽

Sequence Variations ◽

Dna Capture ◽

Dna Chain

DNA molecule will be stretched to its near full contour length inside a nanochannel when the channel diameter is less than the DNA persistence length.1–3 It provides the possibility of real time lab-free-analysis of analysis, such as screening of sequence variations of DNA molecules.3 The key process for this nanochannel-based analysis is to drive DNA molecule electrophoretically through the nanochannel and read out the information of the DNA chain while it is passing the channel.2, 3

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Nanochannel-Confined TAMRA-Polypyrrole Stained DNA Stretching by Varying the Ionic Strength from Micromolar to Millimolar Concentrations

Polymers ◽

10.3390/polym11010015 ◽

2018 ◽

Vol 11 (1) ◽

pp. 15 ◽

Cited By ~ 7

Author(s):

Seonghyun Lee ◽

Yelin Lee ◽

Yongkyun Kim ◽

Cong Wang ◽

Jungyul Park ◽

...

Keyword(s):

Ionic Strength ◽

Double Helix ◽

Persistence Length ◽

Polymer Physics ◽

Structural Deformation ◽

Contour Length ◽

Dna Molecules ◽

Dna Stretching ◽

Single Dna Molecules ◽

Length Changes

Large DNA molecules have been utilized as a model system to investigate polymer physics. However, DNA visualization via intercalating dyes has generated equivocal results due to dye-induced structural deformation, particularly unwanted unwinding of the double helix. Thus, the contour length increases and the persistence length changes so unpredictably that there has been a controversy. In this paper, we used TAMRA-polypyrrole to stain single DNA molecules. Since this staining did not change the contour length of B-form DNA, we utilized TAMRA-polypyrrole stained DNA as a tool to measure the persistence length by changing the ionic strength. Then, we investigated DNA stretching in nanochannels by varying the ionic strength from 0.06 mM to 47 mM to evaluate several polymer physics theories proposed by Odijk, de Gennes and recent papers to deal with these regimes.

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Replication of Bacteriophage 186 DNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009422x ◽

1972 ◽

Vol 30 ◽

pp. 194-195

Author(s):

Dhruba K. Chattoraj ◽

Ross B. Inman

Keyword(s):

Electron Microscopy ◽

Dna Replication ◽

Frame Of Reference ◽

Dna Molecules ◽

E Coli ◽

Phage Dna ◽

Partial Denaturation

Electron microscopy of replicating intermediates has been quite useful in understanding the mechanism of DNA replication in DNA molecules of bacteriophage, mitochondria and plasmids. The use of partial denaturation mapping has made the tool more powerful by providing a frame of reference by which the position of the replicating forks in bacteriophage DNA can be determined on the circular replicating molecules. This provided an easy means to find the origin and direction of replication in λ and P2 phage DNA molecules. DNA of temperate E. coli phage 186 was found to have an unique denaturation map and encouraged us to look into its mode of replication.

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Synchrony of Digestion of SV40 DNA by Exonuclease III Determined by EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116991 ◽

1975 ◽

Vol 33 ◽

pp. 674-675

Author(s):

Ray Wu ◽

G. Ruben ◽

B. Siegel ◽

P. Spielman ◽

E. Jay

Keyword(s):

Dark Field ◽

Uranyl Acetate ◽

Enzyme Digestion ◽

Dna Molecules ◽

Exonuclease Iii ◽

Aluminum Films ◽

Double Stranded Dna ◽

Before And After ◽

Exo Iii ◽

Sv40 Dna

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.

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