Browse
Submit Data
Databases
API
Help

Dataset Information

36 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Conformation Study of Dual Stimuli-Responsive Core-Shell Diblock Polymer Brushes.

ABSTRACT: Stimuli-responsive nanoparticles are among the most popular research topics. In this study, two types of core-shell (polystyrene with a photoiniferter (PSV) as the core and diblock as the shell) polymer brushes (PSV@PNIPA-b-PAA and PSV@PAA-b-PNIPA) were designed and prepared using surface-initiated photoiniferter-mediated polymerization (SI-PIMP). Moreover, their pH- and temperature-stimuli responses were explored by dynamic light scattering (DLS) and turbidimeter under various conditions. The results showed that the conformational change was determined on the basis of the competition among electrostatic repulsion, hydrophobic interaction, hydrogen bonding, and steric hindrance, which was also confirmed by protein adsorption experiments. These results are not only helpful for the design and synthesis of stimuli-responsive polymer brushes but also shed light on controlled protein immobilization under mild conditions.

SUBMITTER: Chen K

PROVIDER: S-EPMC6403727 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Conformation Study of Dual Stimuli-Responsive Core-Shell Diblock Polymer Brushes.

Chen Kaimin K Cao Lan L Zhang Ying Y Li Kai K Qin Xue X Guo Xuhong X

Polymers 20180930 10

Stimuli-responsive nanoparticles are among the most popular research topics. In this study, two types of core-shell (polystyrene with a photoiniferter (PSV) as the core and diblock as the shell) polymer brushes (PSV@PNIPA-<i>b</i>-PAA and PSV@PAA-<i>b</i>-PNIPA) were designed and prepared using surface-initiated photoiniferter-mediated polymerization (SI-PIMP). Moreover, their pH- and temperature-stimuli responses were explored by dynamic light scattering (DLS) and turbidimeter under various con ...[more]

PMID: 30961009

Similar Datasets

Temperature Responsive Diblock Polymer Brushes as Nanoreactors for Silver Nanoparticles Catalysis.

Project description:Metal nanoparticles are widely used in catalysis. Loading metal nanoparticles into polymer brushes has aroused wide attention, but regulation of catalytic performance still needs to be improved. The novel diblock polymer brushes, polystyrene@sodium polystyrene sulfonate-b-poly (N-isopropylacrylamide) (PSV@PSS-b-PNIPA) and PSV@PNIPA-b-PSS with reversed block sequence, were prepared by surface initiated photoiniferter-mediated polymerization (SI-PIMP) and used as nanoreactors to load silver nanoparticles (AgNPs). The block sequence caused the difference of conformation and further affected the catalytic performance. PSV@PNIPA-b-PSS@Ag was found to be able to control the amount of AgNPs exposed to external reactant of 4-nitrophenol at different temperatures to achieve regulation of the reaction rate due to the hydrogen bonds and further physical crosslinking between PNIPA and PSS.

| S-EPMC10146612 | biostudies-literature

Cucurbit[8]uril directed stimuli-responsive supramolecular polymer brushes for dynamic surface engineering.

Project description:In situ modification of surfaces with thin layers of polymers is of growing interest as adjustment of surface properties can be made on demand. We present herein a supramolecular 'grafting to' polymer brush via the recognition of surface-bound cucurbit[8]uril (CB[8]) rotaxanes towards end-functionalised polyethylene glycol (PEG). This dynamic supramolecular method represents advantages over traditional approaches, which employ covalent bond formation in the 'grafting to' process. Brush properties can be easily modified post-preparation by exchanging the polymers with small molecules in a controlled, reversible manner. Including both redox- and light-responsive guests in a single rotaxane entity, the CB[8]-mediated preparation of the polymer brush offers unique opportunities to switch the brush composition efficiently. While the PEG brushes are well hydrated in a good solvent (water) and stretch away from the surface, they collapse in a poor solvent (toluene), leading to the formation of a dense layer on the surface. This collapsed conformation protects the heteroternary complexes of CB[8]-rotaxane from dissociation and maintains the attachment of polymers on the surface.

| S-EPMC5504464 | biostudies-literature

Surface Modification of Silicon Nanowire Based Field Effect Transistors with Stimuli Responsive Polymer Brushes for Biosensing Applications.

Project description:We demonstrate the functionalization of silicon nanowire based field effect transistors (SiNW FETs) FETs with stimuli-responsive polymer brushes of poly(N-isopropylacrylamide) (PNIPAAM) and poly(acrylic acid) (PAA). Surface functionalization was confirmed by atomic force microscopy, contact angle measurements, and verified electrically using a silicon nanowire based field effect transistor sensor device. For thermo-responsive PNIPAAM, the physicochemical properties (i.e., a reversible phase transition, wettability) were induced by crossing the lower critical solution temperature (LCST) of about 32 °C. Taking advantage of this property, osteosarcomic SaoS-2 cells were cultured on PNIPAAM-modified sensors at temperatures above the LCST, and completely detached by simply cooling. Next, the weak polyelectrolyte PAA, that is sensitive towards alteration of pH and ionic strength, was used to cover the silicon nanowire based device. Here, the increase of pH will cause deprotonation of the present carboxylic (COOH) groups along the chains into negatively charged COO- moieties that repel each other and cause swelling of the polymer. Our experimental results suggest that this functionalization enhances the pH sensitivity of the SiNW FETs. Specific receptor (bio-)molecules can be added to the polymer brushes by simple click chemistry so that functionality of the brush layer can be tuned optionally. We demonstrate at the proof-of concept-level that osteosarcomic Saos-2 cells can adhere to PNIPAAM-modified FETs, and cell signals could be recorded electrically. This study presents an applicable route for the modification of highly sensitive, versatile FETs that can be applied for detection of a variety of biological analytes.

| S-EPMC7143225 | biostudies-literature

Novel CD44-targeting and pH/redox-dual-stimuli-responsive core-shell nanoparticles loading triptolide combats breast cancer growth and lung metastasis.

Project description:BackgroundThe toxicity and inefficient delivery of triptolide (TPL) in tumor therapy have greatly limited the clinical application. Thus, we fabricated a CD44-targeting and tumor microenvironment pH/redox-sensitive nanosystem composed of hyaluronic acid-vitamin E succinate and poly (β-amino esters) (PBAEss) polymers to enhance the TPL-mediated suppression of breast cancer proliferation and lung metastasis.ResultsThe generated TPL nanoparticles (NPs) had high drug loading efficiency (94.93% ± 2.1%) and a desirable average size (191 nm). Mediated by the PBAEss core, TPL/NPs displayed a pH/redox-dual-stimuli-responsive drug release profile in vitro. Based on the hyaluronic acid coating, TPL/NPs exhibited selective tumor cellular uptake and high tumor tissue accumulation capacity by targeting CD44. Consequently, TPL/NPs induced higher suppression of cell proliferation, blockage of proapoptotic and cell cycle activities, and strong inhibition of cell migration and invasion than that induced by free TPL in MCF-7 and MDA-MB-231 cells. Importantly, TPL/NPs also showed higher efficacy in shrinking tumor size and blocking lung metastasis with decreased systemic toxicity in a 4T1 breast cancer mouse model at an equivalent or lower TPL dosage compared with that of free TPL. Histological immunofluorescence and immunohistochemical analyses in tumor and lung tissue revealed that TPL/NPs induced a high level of apoptosis and suppressed expression of matrix metalloproteinases, which contributed to inhibiting tumor growth and pulmonary metastasis.ConclusionCollectively, our results demonstrate that TPL/NPs, which combine tumor active targeting and pH/redox-responsive drug release with proapoptotic and antimobility effects, represent a promising candidate in halting breast cancer progression and metastasis while minimizing systemic toxicity.

| S-EPMC8220850 | biostudies-literature

Dual-stimuli-responsive microparticles.

Project description:The need for smart materials in the area of biotechnology has fueled the development of numerous stimuli-responsive polymers. Many of these polymers are responsive to pH, light, temperature, or oxidative stress, and yet very few are responsive toward multiple stimuli. Here we report on the synthesis of a novel dual-stimuli-responsive poly(ethylene glycol)-based polymer capable of changing its hydrophilic properties upon treatment with UV light (exogenous stimulus) and markers of oxidative stress (endogenous stimulus). From this polymer, smart microparticles and fibers were fabricated and their responses to either stimulus separately and in conjunction were examined. Comparison of the degradation kinetics demonstrated that the polymer became water-soluble only after both oxidation and irradiation with UV light, which resulted in selective degradation of the corresponding particles. Furthermore, in vitro experiments demonstrated successful uptake of these particles by Raw 264.7 cells. Such dual-stimuli-responsive particles could have potential applications in drug delivery, imaging, and tissue engineering.

| S-EPMC5665401 | biostudies-literature

FRET-Integrated Polymer Brushes for Spatially Resolved Sensing of Changes in Polymer Conformation.

Project description:Polymer brush surfaces that alter their physical properties in response to chemical stimuli have the capacity to be used as new surface-based sensing materials. For such surfaces, detecting the polymer conformation is key to their sensing capabilities. Herein, we report on FRET-integrated ultrathin (<70 nm) polymer brush surfaces that exhibit stimuli-dependent FRET with changing brush conformation. Poly(N-isopropylacrylamide) polymers were chosen due their exceptional sensitivity to liquid mixture compositions and their ability to be assembled into well-defined polymer brushes. The brush transitions were used to optically sense changes in liquid mixture compositions with high spatial resolution (tens of micrometers), where the FRET coupling allowed for noninvasive observation of brush transitions around complex interfaces with real-time sensing of the liquid environment. Our methods have the potential to be leveraged towards greater surface-based sensing capabilities at intricate interfaces.

| S-EPMC8361709 | biostudies-literature

Stimuli-responsive mechanically adaptive polymer nanocomposites.

Project description:A new series of biomimetic stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was prepared and investigated. The materials were produced by introducing percolating networks of cellulose nanofibers or "whiskers" derived from tunicates into poly(vinyl acetate) (PVAc), poly(butyl methacrylate) (PBMA), and blends of these polymers, with the objective of determining how the hydrophobicity and glass-transition temperature (Tg) of the polymer matrix affect the water-induced mechanically dynamic behavior. Below the Tg (approximately 60-70 degrees C), the incorporation of whiskers (15.1-16.5% v/v) modestly increased the tensile storage moduli (E') of the neat polymers from 0.6 to 3.8 GPa (PBMA) and from 2 to 5.2 GPa (PVAc). The reinforcement was much more dramatic above Tg, where E' increased from 1.2 to 690 MPa (PVAc) and approximately 1 MPa to 1.1 GPa (PBMA). Upon exposure to physiological conditions (immersion in artificial cerebrospinal fluid, ACSF, at 37 degrees C) all materials displayed a decrease in E'. The most significant contrast was seen in PVAc; for example, the E' of a 16.5% v/v PVAc/whisker nanocomposite decreased from 5.2 GPa to 12.7 MPa. Only a modest modulus decrease was measured for PBMA/whisker nanocomposite; here the E' of a 15.1% v/v PBMA/whisker nanocomposite decreased from 3.8 to 1.2 GPa. A systematic investigation revealed that the magnitude of the mechanical contrast was related to the degree of swelling with ACSF, which was shown to increase with whisker content, temperature, and polarity of the matrix (PVAc>PBMA). The mechanical morphing of the new materials can be described in the framework of both the percolation and Halpin-Kardos models for nanocomposite reinforcement, and is the result of changing interactions among the nanoparticles and plasticization of the matrix upon swelling.

| S-EPMC2840258 | biostudies-literature

Responsive Adsorption of N-Isopropylacrylamide Based Copolymers on Polymer Brushes.

Project description:We investigate the adsorption of pH- or temperature-responsive polymer systems by ellipsometry and neutron reflectivity. To this end, temperature-responsive poly (N-isopropylacrylamide) (PNIPAM) brushes and pH-responsive poly (acrylic acid) (PAA) brushes have been prepared using the "grafting onto" method to investigate the adsorption process of polymers and its reversibility under controlled environment. To that purpose, macromolecular brushes were designed with various chain lengths and a wide range of grafting density. Below the transition temperature (LCST), the characterization of PNIPAM brushes by neutron reflectivity shows that the swelling behavior of brushes is in good agreement with the scaling models before they collapse above the LCST. The reversible adsorption on PNIPAM brushes was carried out with linear copolymers of N-isopropylacrylamide and acrylic acid, P(NIPAM-co-AA). While these copolymers remain fully soluble in water over the whole range of temperature investigated, a quantitative adsorption driven by solvophobic interactions was shown to proceed only above the LCST of the brush and to be totally reversible upon cooling. Similarly, the pH-responsive adsorption driven by electrostatic interactions on PAA brushes was studied with copolymers of NIPAM and N,N-dimethylaminopropylmethacrylamide, P(NIPAM-co-MADAP). In this case, the adsorption of weak polycations was shown to increase with the ionization of the PAA brush with interactions mainly located in the upper part of the brush at pH 7 and more deeply adsorbed within the brush at pH 9.

| S-EPMC7022643 | biostudies-literature

"Smart" diblock copolymers as templates for magnetic-core gold-shell nanoparticle synthesis.

Project description:We report a new strategy for synthesizing temperature-responsive gamma-Fe(2)O(3)-core/Au-shell nanoparticles (Au-mNPs) from diblock copolymer micelles. The amphiphilic diblock copolymer chains were synthesized using reversible addition-fragmentation chain-transfer (RAFT) with a thermally responsive "smart" poly(N-isopropylacrylamide) (pNIPAAm) block and an amine-containing poly(N,N-dimethylaminoethylacrylamide) (DMAEAm) block that acted as a reducing agent during gold shell formation. The Au-mNPs reversibly aggregated upon heating the solution above the transition temperature of pNIPAAm, resulting in a red-shifted localized surface plasmon resonance.

| S-EPMC2806508 | biostudies-literature

One-Step Fabrication of Stimuli-Responsive Chitosan-Platinum Brushes for Listeria monocytogenes Detection.

Project description:Bacterial contamination in food-processing facilities is a critical issue that leads to outbreaks compromising the integrity of the food supply and public health. We developed a label-free and rapid electrochemical biosensor for Listeria monocytogenes detection using a new one-step simultaneous sonoelectrodeposition of platinum and chitosan (CHI/Pt) to create a biomimetic nanostructure that actuates under pH changes. The XPS analysis shows the effective co-deposition of chitosan and platinum on the electrode surface. This deposition was optimized to enhance the electroactive surface area by 11 times compared with a bare platinum-iridium electrode (p < 0.05). Electrochemical behavior during chitosan actuation (pH-stimulated osmotic swelling) was characterized with three different redox probes (positive, neutral, and negative charge) above and below the isoelectric point of chitosan. These results showed that using a negatively charged redox probe led to the highest electroactive surface area, corroborating previous studies of stimulus-response polymers on metal electrodes. Following this material characterization, CHI/Pt brushes were functionalized with aptamers selective for L. monocytogenes capture. These aptasensors were functional at concentrations up to 106 CFU/mL with no preconcentration nor extraneous reagent addition. Selectivity was assessed in the presence of other Gram-positive bacteria (Staphylococcus aureus) and with a food product (chicken broth). Actuation led to improved L. monocytogenes detection with a low limit of detection (33 CFU/10 mL in chicken broth). The aptasensor developed herein offers a simple fabrication procedure with only one-step deposition followed by functionalization and rapid L. monocytogenes detection, with 15 min bacteria capture and 2 min sensing.

| S-EPMC8699315 | 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