Browse
Submit Data
Databases
API
Help

Dataset Information

15 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Loose-fit polypseudorotaxanes constructed from ?-CDs and PHEMA-PPG-PEG-PPG-PHEMA.

ABSTRACT: A pentablock copolymer was prepared via the atom transfer radical polymerization of 2-hydroxyethyl methacrylate (HEMA) initiated by 2-bromoisobutyryl end-capped PPO-PEO-PPO as a macroinitiator in DMF. Attaching PHEMA blocks altered the self-assembly process of the pentablock copolymer with ?-CDs in aqueous solution. Before attaching the PHEMA, the macroinitiator was preferentially bent to pass through the inner cavity of ?-CDs to give rise to tight-fit double-chain stranded polypseudorotaxanes (PPRs). After attaching the PHEMA, the resulting pentablock copolymer was single-chain stranded into the interior of ?-CDs to form more stable, loose-fit PPRs. The results of (1)H NMR, WXRD, DSC, TGA, (13)C CP/MAS NMR and FTIR analyses indicated that ?-CDs can accommodate and slip over PHEMA blocks to randomly distribute along the entire pentablock copolymer chain. This results in unique, single-chain stranded PPRs showing no characteristic channel-type crystal structure.

SUBMITTER: Kong T

PROVIDER: S-EPMC4222382 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Loose-fit polypseudorotaxanes constructed from γ-CDs and PHEMA-PPG-PEG-PPG-PHEMA.

Kong Tao T Ye Lin L Zhang Ai-Ying AY Feng Zeng-Guo ZG

Beilstein journal of organic chemistry 20141023

A pentablock copolymer was prepared via the atom transfer radical polymerization of 2-hydroxyethyl methacrylate (HEMA) initiated by 2-bromoisobutyryl end-capped PPO-PEO-PPO as a macroinitiator in DMF. Attaching PHEMA blocks altered the self-assembly process of the pentablock copolymer with γ-CDs in aqueous solution. Before attaching the PHEMA, the macroinitiator was preferentially bent to pass through the inner cavity of γ-CDs to give rise to tight-fit double-chain stranded polypseudorotaxanes ( ...[more]

PMID: 25383117

Similar Datasets

Modification of Thermal and Mechanical Properties of PEG-PPG-PEG Copolymer (F127) with MA-POSS.

Project description:Pluronic F127 exhibits thermogelling behaviour at 20⁻30 °C via a micelle packing mechanism. Disruption of the micelle packing increases the sol-gel temperature, but results in the decrease of modulus. Herein, we reported a method to modify F127 with polyhedral oligosilsesquioxane (POSS) to impart a higher gelling temperature without yielding the property and strength of the thermogel. The thermal degradation temperature was enhanced to 15 °C after POSS incorporation and the gelling temperature shifted 10 °C higher, without sacrificing the modulus of the gel. Rheological studies supported the claim that the gel property was reinforced after POSS incorporation. F127-POSS copolymer matrix stored more energy from POSS reinforcement, which saw larger Lissajous curve areas before the collapse of the microstructure for the same amount of stress applied. These results indicated that modification with POSS would raise the sol-gel transition temperature without sacrificing the modulus of the gel.

| S-EPMC6432308 | biostudies-other

Structure-property relationship for in vitro siRNA delivery performance of cationic 2-hydroxypropyl-β-cyclodextrin: PEG-PPG-PEG polyrotaxane vectors.

Project description:Nanoparticle-mediated siRNA delivery is a promising therapeutic approach, however, the processes required for transport of these materials across the numerous extracellular and intracellular barriers are poorly understood. Efficient delivery of siRNA-containing nanoparticles would ultimately benefit from an improved understanding of how parameters associated with these barriers relate to the physicochemical properties of the nanoparticle vectors. We report the synthesis of three Pluronic(®)-based, cholesterol end-capped cationic polyrotaxanes (PR(+)) threaded with 2-hydroxypropyl-β-cyclodextrin (HPβCD) for siRNA delivery. The biological data showed that PR(+):siRNA complexes were well tolerated (∼90% cell viability) and produced efficient silencing (>80%) in HeLa-GFP and NIH 3T3-GFP cell lines. We further used a multi-parametric approach to identify relationships between the PR(+) structure, PR(+):siRNA complex physical properties, and biological activity. Small angle X-ray scattering and cryoelectron microscopy studies reveal periodicity and lamellar architectures for PR(+):siRNA complexes, whereas the biological assays, ζ potential measurements, and imaging studies suggest that silencing efficiency is influenced by the effective charge ratio (ρeff), polypropylene oxide (PO) block length, and central PO block coverage (i.e., rigidity) of the PR(+) core. We infer from our findings that more compact PR(+):siRNA nanostructures arising from lower molecular weight, rigid rod-like PR(+) polymer cores produce improved silencing efficiency relative to higher molecular weight, more flexible PR(+) vectors of similar effective charge. This study demonstrates that PR(+):siRNA complex formulations can be produced having higher performance than Lipofectamine(®) 2000, while maintaining good cell viability and siRNA sequence protection in cell culture.

| S-EPMC4755830 | biostudies-literature

Thermosensitive Poly(DHSe/PEG/PPG Urethane)-Based Hydrogel Extended Remdesivir Application in Ophthalmic Medication.

Project description:The spread of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) outbreak beginning in March 2020. Currently, there is a lack of suitable dose formulations that interrupt novel coronavirus transmission via corneal and conjunctival routes. In the present study, we developed and evaluated a thermosensitive gelling system based on a selenium-containing polymer for topical ocular continuous drug release. In detail, di-(1-hydroxylundecyl) selenide (DHSe), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) were polymerized to form poly(DHSe/PEG/PPG urethane). The polymer was used to carry poorly water-soluble remdesivir (RDV) at room temperature to form the final thermosensitive in situ gel, which exhibited a typical sol-gel transition at 35 °C. The formed polymer was further characterized by rheology, thermology, and scanning electron microscopy. In vitro release studies and in vivo retention and penetration tests indicated that the thermogel provided the prolonged release of RDV. The RDV-loaded in situ gel was proven to be non-biotoxic against human corneal epithelial cells, with good ocular tolerance and biocompatibility in rabbit eyes.

| S-EPMC8778792 | biostudies-literature

Reduced cytotoxicity of insulin-immobilized CdS quantum dots using PEG as a spacer.

Project description:Cytotoxicity is a severe problem for cadmium sulfide nanoparticles (CSNPs) in biological systems. In this study, mercaptoacetic acid-coated CSNPs, typical semiconductor Q-dots, were synthesized in aqueous medium by the arrested precipitation method. Then, amino-terminated polyethylene glycol (PEG) was conjugated to the surface of CSNPs (PCSNPs) in order to introduce amino groups to the surface. Finally, insulin was immobilized on the surface of PCSNPs (ICSNPs) to reduce cytotoxicity as well as to enhance cell compatibility. The presence of insulin on the surface of ICSNPs was confirmed by observing infrared absorptions of amide I and II. The mean diameter of ICSNPs as determined by dynamic light scattering was about 38 nm. Human fibroblasts were cultured in the absence and presence of cadmium sulfide nanoparticles to evaluate cytotoxicity and cell compatibility. The results showed that the cytotoxicity of insulin-immobilized cadmium sulfide nanoparticles was significantly suppressed by usage of PEG as a spacer. In addition, cell proliferation was highly facilitated by the addition of ICSNPs. The ICSNPs used in this study will be potentials to be used in bio-imaging applications.

| S-EPMC3228607 | biostudies-literature

PEG/PPG-PDMS-Adamantane-based Crosslinked Terpolymer Using the ROMP Technique to Prepare a Highly Permeable and CO2-Selective Polymer Membrane.

Project description:In this study, precursor molecules based on PEG/PPG and polydimethylsiloxane (PDMS), both widely used rubbery polymers, were copolymerized with bulky adamantane into copolymer membranes. Ring-opening metathesis polymerization (ROMP) was employed during the polymerization process to create a structure with both ends crosslinked. The precursor molecules and corresponding polymer membranes were characterized using various analytical methods. The polymer membranes were fabricated using different compositions of PDMS and adamantane, to determine how the network structure affected their gas separation performance. PEG/PPG, in which CO2 is highly soluble, was copolymerized with PDMS, which has high permeability, and adamantane, which controlled the crosslinking density with a rigid and bulky structure. It was confirmed that the resulting crosslinked polymer membranes exhibited high solubility and diffusivity for CO2. Further, their crosslinked structure using ROMP technique made it possible to form good films. The membranes fabricated in the present study exhibited excellent performance, i.e., CO2 permeability of up to 514.5 Barrer and CO2/N2 selectivity of 50.9.

| S-EPMC7464022 | biostudies-literature

Brno University of Technology Smartphone PPG Database (BUT PPG): Annotated Dataset for PPG Quality Assessment and Heart Rate Estimation.

Project description:To the best of our knowledge, there is no annotated database of PPG signals recorded by smartphone publicly available. This article introduces Brno University of Technology Smartphone PPG Database (BUT PPG) which is an original database created by the cardiology team at the Department of Biomedical Engineering, Brno University of Technology, for the purpose of evaluating photoplethysmographic (PPG) signal quality and estimation of heart rate (HR). The data comprises 48 10-second recordings of PPGs and associated electrocardiographic (ECG) signals used for determination of reference HR. The data were collected from 12 subjects (6 female, 6 male) aged between 21 and 61. PPG data were collected by smartphone Xiaomi Mi9 with sampling frequency of 30 Hz. Reference ECG signals were recorded using a mobile ECG recorder (Bittium Faros 360) with a sampling frequency of 1,000 Hz. Each PPG signal includes annotation of quality created manually by biomedical experts and reference HR. PPG signal quality is indicated binary: 1 indicates good quality for HR estimation, 0 indicates signals where HR cannot be detected reliably, and thus, these signals are unsuitable for further analysis. As the only available database containing PPG signals recorded by smartphone, BUT PPG is a unique tool for the development of smart, user-friendly, cheap, on-the-spot, self-home-monitoring of heart rate with the potential of widespread using.

| S-EPMC8440059 | biostudies-literature

Differentiation between mechanically loose and fixed press-fit implants using quantitative acoustics and load self-referencing: A phantom study on shoulder prostheses in polyurethane foam.

Project description:This study proposes to use cross-interface quantitative acoustics (ci-qA) and load self-referencing (LSR) to assess implant stability in a radiation-free, inexpensive, rapid, and quantitative manner. Eight bone analog specimens, made from polyurethane foam, were implanted with a cementless stemless shoulder implant-first in a fixed and later in a loose configuration-and measured using ci-qA under two load conditions. The loose implants exhibited higher micromotion and lower pull-out strength than their stable counterparts, with all values falling within the range of reported reference values. All acoustic characteristics differentiated between loose and fixed implants (maximum area-under-curve AUC = 1.0 for mean total signal energy, AUC = 1.0 for mean total signal energy ratio, AUC = 0.8 for harmonic ratio, and AUC = 0.92 for load self-referencing coefficient). While these results on bone substitute material will need to be confirmed on real bone specimen, ci-qA could ultimately facilitate the assessment of primary stability during implantation surgery and avoid unnecessary revision through quantitative evaluation of secondary stability during follow-up.

| S-EPMC7259646 | biostudies-literature

Fe-FIT-Diff

Project description:au13-06_fit - Fe-FIT-Diff - FIT (FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR) is a regulator of Fe deficiency responses in the root. FIT is a basic helix-loop-helix protein. Here, we investigated the transcriptome changes in response to Fe deficiency (- Fe) versus the control condition (+ Fe) in wild type, the fit-3 loss of function mutant and in FIT overexpression plants.

2015-02-14 | GSE65934 | GEO

PPG: online generation of protein pictures and animations.

Project description:The protein picture generator (PPG) is an online service to generate pictures of a protein structure. Its design was conceived as an answer to the need expressed by a part of the community to have some means to produce simply complex pictures to insert in publications or in presentations. PPG can produce static or animated pictures. It can be accessed at http://bioserv.rpbs.jussieu.fr/cgi-bin/PPG.

| S-EPMC1160153 | biostudies-literature

Dataset from PPG wireless sensor for activity monitoring.

Project description:We introduce a dataset to provide insights about the photoplethysmography (PPG) signal captured from the wrist in presence of motion artifacts and the accelerometer signal, simultaneously acquired from the same wrist. The data presented were collected by the electronics research team of the Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy. This article describes data recorded from 7 subjects and includes 105 PPG signals (15 for each subject) and the corresponding 105 tri-axial accelerometer signals measured with a sampling frequency of 400 Hz. These data can be reused for testing machine learning algorithms for human activity recognition.

| S-EPMC6971339 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data