Dataset Information

Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform.

ABSTRACT: We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by (1)H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is "frozen" at high temperatures (above 260 K), but it unexpectedly becomes "unfrozen" at temperatures below 250 K (i.e., melting when cooling). The transition between these two states occurs within a small temperature range (~10 K). Such a behavior is not observed for smaller dendrimer generations (G = 1 and 3). This effect is likely related to the low critical solution temperature (LCST) of PEG and is caused by dendrimer conformations, in which the PEG group concentration in the layer increases with growing G. We suppose that the unusual behavior of PEG fragments in dendrimers will be interesting for practical applications such as nanocontainers or nanoreactors.

SUBMITTER: Markelov DA

PROVIDER: S-EPMC4823654 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

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Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform.

Markelov Denis A DA Matveev Vladimir V VV Ingman Petri P Nikolaeva Marianna N MN Penkova Anastasia V AV Lahderanta Erkki E Boiko Natalia I NI Chizhik Vladimir I VI

Scientific reports 20160407

We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by (1)H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is "frozen" at high tempe ...[more]

PMID: 27052599

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Project description:The primary concentration and molecular process are critical to implement wastewater-based epidemiology for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the previously developed methods were optimized for nonenveloped viruses. Few studies evaluated if the methods are applicable to the efficient recovery of enveloped viruses from various types of raw sewage. This study aims (1) to compare the whole process recovery of Pseudomonas phage ?6, a surrogate for enveloped viruses, among combinations of primary concentration [ultrafiltration (UF), electronegative membrane vortex (EMV), and polyethylene glycol precipitation (PEG)] and RNA extraction methods (spin column-based method using QIAamp Viral RNA Mini Kit and acid guanidinium thiocyanate-phenol-chloroform extraction using TRIzol reagent) for three types of raw sewage and (2) to test the applicability of the method providing the highest ?6 recovery to the detection of SARS-CoV-2 RNA. Among the tested combinations, PEG+TRIzol provided the highest ?6 recovery ratio of 29.8% to 49.8% (geometric mean). UF + QIAamp Viral RNA Mini Kit provided the second highest ?6 recovery of 6.4% to 35.8%. The comparable ?6 recovery was observed for UF + TRIzol (13.8-30.0%). PEG + QIAamp Viral RNA Mini Kit provided only 1.4% to 3.0% of ?6 recovery, while coliphage MS2, a surrogate for nonenveloped viruses, was recovered comparably with PEG + TRIzol. This indicated that the nonenveloped surrogate (MS2) did not necessarily validate the efficient recovery for enveloped viruses. EMV + QIAamp Viral RNA Mini Kit provided significantly different ?6 recovery (1.6-21%) among the types of raw sewage. Then, the applicability of modified PEG + TRIzol was examined for the raw sewage collected in Tokyo, Japan. Of the 12 grab samples, 4 were positive for SARS-CoV-2 CDC N1 and N3 assay. Consequently, PEG + TRIzol provided the highest ?6 recovery and allowed for the detection of SARS-CoV-2 RNA from raw sewage.

Dataset Information

Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform.

Publications

Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform.

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