Köster, Sarah

[["dc.bibliographiccitation.firstpage","2167"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Biomacromolecules"],["dc.bibliographiccitation.lastpage","2172"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Pfohl, Thomas"],["dc.contributor.author","Otten, Alexander"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Dootz, Rolf"],["dc.contributor.author","Struth, Bernd"],["dc.contributor.author","Evans, Heather M."],["dc.date.accessioned","2017-09-07T11:49:28Z"],["dc.date.available","2017-09-07T11:49:28Z"],["dc.date.issued","2007"],["dc.description.abstract","DNA condensation in vivo usually requires proteins and/or multivalent salts. Here, we explore the in vitro compaction of DNA by cationic dendrimers having an intermediate size and charge. The dynamic assembly of DNA-dendrimer mesophases is discernible due to the laminar flow in a specially designed X-ray compatible microfluidic device. The setup ensures a nonequilibrium ascent of reactant concentration, and the resulting progression of DNA compaction was detected online using microfocused small-angle X-ray diffraction. The evolution of a DNA-dendrimer columnar square mesophase as a function of increasing dendrimer content is described. Additionally, in regions of maximum shear, an unexpected high-level perpendicular ordering of this phase is recorded. Furthermore, these assemblies are found to be in coexistence with a densely packed DNA-only mesophase in regions of excess DNA. The latter is reminiscent of dense packing found in bacteriophage and chromosomes, although surprisingly, it is not stabilized by direct dendrimer contact."],["dc.identifier.doi","10.1021/bm070317s"],["dc.identifier.gro","3143474"],["dc.identifier.isi","000247820000019"],["dc.identifier.pmid","17579478"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/992"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1525-7797"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","molecular biophysics"],["dc.subject.gro","microfluidics"],["dc.title","Highly packed and oriented DNA mesophases identified using in situ microfluidic X-ray microdiffraction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","745"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","750"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Otten, Alexander"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Struth, Bernd"],["dc.contributor.author","Snigirev, Anatoly"],["dc.contributor.author","Pfohl, Thomas"],["dc.date.accessioned","2017-09-07T11:53:40Z"],["dc.date.available","2017-09-07T11:53:40Z"],["dc.date.issued","2005"],["dc.description.abstract","The combination of X- ray microdiffraction and microfluidics is used to investigate the dynamic behaviour of soft materials. A microfocused X- ray beam enables the observation of the influence of droplet formation on the nanostructure of a smectic liquid crystal in water. Using a hydrodynamic focusing device, the evolution of the intercalation of DNA into multilamellar membranes can be studied. Owing to the elongational flow at the centre of this device, alignment of the material is induced which allows for an improved structural characterization. Furthermore, the influence of strain applied to these materials can be tested."],["dc.identifier.doi","10.1107/S0909049505013580"],["dc.identifier.gro","3143792"],["dc.identifier.isi","000232619300009"],["dc.identifier.pmid","16239743"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/1344"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","0909-0495"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","molecular biophysics"],["dc.subject.gro","microfluidics"],["dc.title","Microfluidics of soft matter investigated by small-angle X-ray scattering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","217"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Bulletin of the Polish Academy of Sciences. Technical sciences"],["dc.bibliographiccitation.lastpage","227"],["dc.bibliographiccitation.volume","55"],["dc.contributor.author","Evans, H. M."],["dc.contributor.author","Dootz, Rolf"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Struth, Bernd"],["dc.contributor.author","Pfohl, Thomas"],["dc.date.accessioned","2017-09-07T11:49:28Z"],["dc.date.available","2017-09-07T11:49:28Z"],["dc.date.issued","2007"],["dc.description.abstract","The study of liquid crystalline assemblies, with an emphasis on biological phenomena, is now accessible using newly developed microdevices integrated with X-ray analysis capability. Many biological systems can be described in terms of gradients, mixing, and confinement, all of which can be mimicked with the use of appropriate microfluidic designs. The use of hydrodynamic focusing creates well-defined mixing conditions that vary depending on parameters such as device geometry, and can be quantified with finite element modelling. We describe experiments in which geometry and strain rate induce finite changes in liquid crystalline orientation. We also demonstrate the online supramolecular assembly of lipoplexes. The measurement of lipoplex orientation as a function of flow velocity allows us to record a relaxation process of the lipoplexes, as evidenced by a remarkable 4-fold azimuthal symmetry. All of these processes are accessible due to the intentional integration of design elements in the microdevices."],["dc.identifier.gro","3143487"],["dc.identifier.isi","000255242300011"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/1006"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","0239-7528"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","molecular biophysics"],["dc.subject.gro","microfluidics"],["dc.title","X-ray microdiffraction on flow-controlled biomolecular assemblies"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","639"],["dc.bibliographiccitation.issue","18"],["dc.bibliographiccitation.journal","Journal of Physics: Condensed Matter"],["dc.bibliographiccitation.lastpage","652"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Dootz, Rolf"],["dc.contributor.author","Otten, Alexander"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Struth, Bernd"],["dc.contributor.author","Pfohl, Thomas"],["dc.date.accessioned","2017-09-07T11:53:15Z"],["dc.date.available","2017-09-07T11:53:15Z"],["dc.date.issued","2006"],["dc.description.abstract","Combining microfluidics with x-ray microdiffraction and Raman microscopy, the dynamic behaviour of soft matter, with specific consideration of the molecular structure, can be investigated. Microfluidic systems enable a reduction of sample volume and shorter reaction times. By performing experiments under continuous microflow, material damage is avoided and the influence of external stress on biomacromolecules can be analysed. The generated elongated flow induces alignment of the investigated materials, allowing for an improved structural characterization. Here, the dynamics of the compaction of DNA by polypropyleneimine dotriacontaamine dendrimers, generation 4 is studied. As a consequence of the laminar flow inside the microchannels, highly defined, diffusion-controlled compaction of the DNA occurs enabling the study of different states of the reaction during one measurement by varying the observation position in the channels. The evolution of a columnar mesophase with an in-plane square symmetry is monitored by x-ray microdiffraction and the molecular interaction between the two reactants is traced using Raman microscopy, leading to a more profound comprehension of the condensation reaction. The experimental results are in accordance with finite element method simulations of the flow and diffusion profiles in the elongated flow device."],["dc.identifier.doi","10.1088/0953-8984/18/18/s10"],["dc.identifier.gro","3145050"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/2743"],["dc.language.iso","en"],["dc.notes.intern","Crossref Import"],["dc.notes.status","final"],["dc.relation.issn","0953-8984"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","molecular biophysics"],["dc.subject.gro","microfluidics"],["dc.title","Evolution of DNA compaction in microchannels"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]