scholarly journals Wavelength-Gated Photoreversible Polymerization and Topology Control

2020 ◽  
Author(s):  
Hendrik Frisch ◽  
Kai Mundsinger ◽  
Berwyck Poad ◽  
Stephen Blanksby ◽  
Christopher Barner-Kowollik
Keyword(s):  
Ion Mobility ◽  
Building Blocks ◽  
Wavelength Dependence ◽  
Size Exclusion ◽  
High Molar Mass ◽  
Mobility Data ◽  
And Topology ◽  
Topology Formation ◽  
Exclusion Chromatography ◽  
Controlled Topology

We exploit the wavelength dependence of [2+2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks. Blue light affords high molar mass polymers that are stable at wavelengths exceeding 430 nm yet highly responsive to shorter wavelengths. UVB irradiation induces a rapid depolymerization yielding linear oligomers, whereas violet light generates cyclic entities. Different colors of light thus allow switching between a depolymerization that either proceeds through cyclic or linear topologies. The light-controlled topology formation was evidenced by correlation of mass spectrometry (MS) with size exclusion chromatography (SEC) and ion mobility data.<br>

scholarly journals Wavelength-Gated Photoreversible Polymerization and Topology Control

2020 ◽  
Author(s):  
Hendrik Frisch ◽  
Kai Mundsinger ◽  
Berwyck Poad ◽  
Stephen Blanksby ◽  
Christopher Barner-Kowollik
Keyword(s):  
Ion Mobility ◽  
Building Blocks ◽  
Wavelength Dependence ◽  
Size Exclusion ◽  
High Molar Mass ◽  
Mobility Data ◽  
And Topology ◽  
Topology Formation ◽  
Exclusion Chromatography ◽  
Controlled Topology

We exploit the wavelength dependence of [2+2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks. Blue light affords high molar mass polymers that are stable at wavelengths exceeding 430 nm yet highly responsive to shorter wavelengths. UVB irradiation induces a rapid depolymerization yielding linear oligomers, whereas violet light generates cyclic entities. Different colors of light thus allow switching between a depolymerization that either proceeds through cyclic or linear topologies. The light-controlled topology formation was evidenced by correlation of mass spectrometry (MS) with size exclusion chromatography (SEC) and ion mobility data.<br>

scholarly journals Kinetics and Topology of DNA Associated with Circulating Extracellular Vesicles Released during Exercise

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 522
Author(s):  
Elmo W. I. Neuberger ◽  
Barlo Hillen ◽  
Katharina Mayr ◽  
Perikles Simon ◽  
Eva-Maria Krämer-Albers ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Size Exclusion ◽  
Affinity Capture ◽  
Healthy Humans ◽  
Dnase Digestion ◽  
And Topology ◽  
Single Bout ◽  
Exclusion Chromatography ◽  
Free Circulating Dna ◽  
Line Elements

Although it is widely accepted that cancer-derived extracellular vesicles (EVs) carry DNA cargo, the association of cell-free circulating DNA (cfDNA) and EVs in plasma of healthy humans remains elusive. Using a physiological exercise model, where EVs and cfDNA are synchronously released, we aimed to characterize the kinetics and localization of DNA associated with EVs. EVs were separated from human plasma using size exclusion chromatography or immuno-affinity capture for CD9+, CD63+, and CD81+ EVs. DNA was quantified with an ultra-sensitive qPCR assay targeting repetitive LINE elements, with or without DNase digestion. This model shows that a minute part of circulating cell-free DNA is associated with EVs. During rest and following exercise, only 0.12% of the total cfDNA occurs in association with CD9+/CD63+/CD81+EVs. DNase digestion experiments indicate that the largest part of EV associated DNA is sensitive to DNase digestion and only ~20% are protected within the lumen of the separated EVs. A single bout of running or cycling exercise increases the levels of EVs, cfDNA, and EV-associated DNA. While EV surface DNA is increasing, DNAse-resistant DNA remains at resting levels, indicating that EVs released during exercise (ExerVs) do not contain DNA. Consequently, DNA is largely associated with the outer surface of circulating EVs. ExerVs recruit cfDNA to their corona, but do not carry DNA in their lumen.

scholarly journals Wavelength-gated photoreversible polymerization and topology control

2020 ◽  
Vol 11 (10) ◽  
pp. 2834-2842 ◽  
Author(s):  
Hendrik Frisch ◽  
Kai Mundsinger ◽  
Berwyck L. J. Poad ◽  
Stephen J. Blanksby ◽  
Christopher Barner-Kowollik
Keyword(s):  
Topology Control ◽  
Building Blocks ◽  
Wavelength Dependence ◽  
And Topology

We exploit the wavelength dependence of [2 + 2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks.

scholarly journals A Supramolecular Assembly of Hemoproteins Formed in a Star-Shaped Structure via Heme–Heme Pocket Interactions

2021 ◽  
Vol 22 (3) ◽  
pp. 1012
Author(s):  
Julian Wong Soon ◽  
Koji Oohora ◽  
Shota Hirayama ◽  
Takashi Hayashi
Keyword(s):  
Supramolecular Assembly ◽  
Building Blocks ◽  
Size Exclusion ◽  
Hydrodynamic Diameter ◽  
Prosthetic Group ◽  
Heme Pocket ◽  
Cytochrome B562 ◽  
Sds Page ◽  
Vis Spectroscopy ◽  
Exclusion Chromatography

Proteins have been used as building blocks to provide various supramolecular structures in efforts to develop nano-biomaterials possessing broad biological functionalities. A series of unique structures have been obtained from the engineering of hemoproteins which contain the iron porphyrin known as heme, as a prosthetic group. This work in developing assembling systems is extended using cytochrome b562, a small electron transfer hemoprotein engineered to include an externally-attached heme moiety. The engineered units, which form a one-dimensional assembly via interprotein heme–heme pocket interactions, are conjugated to an apo-form of hexameric tyrosine-coordinated hemoprotein (apoHTHP) to provide a branching unit promoting the assembly of a star-shaped structure. The incorporation of the heme moiety attached to the protein surface of cytochrome b562 into apoHTHP can be accelerated by elevating the reaction temperature to generate a new assembly. The formation of a new larger assembly structure was confirmed by size exclusion chromatography. The ratio of the heme-containing units in the assemblies was analyzed by UV-Vis spectroscopy and the population of protein units estimated from SDS PAGE suggests the presence of plausible star-shaped structures, which are supported by hydrodynamic diameter data obtained by dynamic light scattering.

scholarly journals Temperature Gradient Interaction Chromatography: A Perspective

2021 ◽  
Author(s):  
Lian R. Hutchings ◽  
Antonella Pagliarulo
Keyword(s):  
Liquid Chromatography ◽  
Temperature Gradient ◽  
Molar Mass ◽  
Reversed Phase ◽  
Normal Phase ◽  
Branched Polymers ◽  
Size Exclusion ◽  
Advanced Technique ◽  
High Molar Mass ◽  
Exclusion Chromatography

AbstractThe application of temperature gradient interaction chromatography (TGIC) as an advanced technique for the characterisation of polymers is discussed, in comparison to other liquid chromatography techniques and in particular the ubiquitous size exclusion chromatography. Specifically, the use of reversed-phase TGIC for the interrogation of complex branched polymers and normal-phase TGIC for characterisation of high-molar mass end-functionalised polymers is highlighted.

Sign in / Sign up

Export Citation Format

Share Document