New poly(amino acid methacrylate) brush supports the formation of well-defined lipid membranes.
Ontology highlight
ABSTRACT:
SUBMITTER: Blakeston AC
PROVIDER: S-EPMC4444997 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Poly(2-aminoethyl methacrylate) (PAEM) homopolymers with defined chain length and narrow molecular weight distribution were synthesized using atom transfer radical polymerization (ATRP), and a comprehensive study was conducted to evaluate the colloidal properties of PAEM/plasmid DNA polyplexes, the uptake and subcellular trafficking of polyplexes in antigen-presenting dendritic cells (DCs), and the biological performance of PAEM as a potential DNA vaccine carrier. PAEM of different chain length (45, 75, and 150 repeating units) showed varying strength in condensing plasmid DNA into narrowly dispersed nanoparticles with very low cytotoxicity. Longer polymer chain length resulted in higher levels of overall cellular uptake and nuclear uptake of plasmid DNA, but shorter polymer chains favored intracellular and intranuclear release of free plasmid from the polyplexes. Despite its simple chemical structure, PAEM transfected DCs very efficiently in vitro in media with or without serum and led to phenotypic maturation of DCs. When a model antigen-encoding ovalbumin plasmid was used, transfected DCs stimulated the activation of naïve CD8(+) T cells to produce high levels of interferon-?. The efficiency of transfection, DC maturation, and CD8(+) T cell activation showed varying degrees of polymer chain-length dependence. These structurally defined cationic polymers may have much potential as efficient DNA vaccine carriers and immunostimulatory adjuvants. They may also serve as a model material system for elucidating structural and intracellular mechanisms of polymer-mediated DNA vaccine delivery.
| S-EPMC3237717 | biostudies-literature
Project description:A new cysteine-based methacrylic monomer (CysMA) was conveniently synthesized via selective thia-Michael addition of a commercially available methacrylate-acrylate precursor in aqueous solution without recourse to protecting group chemistry. Poly(cysteine methacrylate) (PCysMA) brushes were grown from the surface of silicon wafers by atom-transfer radical polymerization. Brush thicknesses of ca. 27 nm were achieved within 270 min at 20 °C. Each CysMA residue comprises a primary amine and a carboxylic acid. Surface zeta potential and atomic force microscopy (AFM) studies of the pH-responsive PCysMA brushes confirm that they are highly extended either below pH 2 or above pH 9.5, since they possess either cationic or anionic character, respectively. At intermediate pH, PCysMA brushes are zwitterionic. At physiological pH, they exhibit excellent resistance to biofouling and negligible cytotoxicity. PCysMA brushes undergo photodegradation: AFM topographical imaging indicates significant mass loss from the brush layer, while XPS studies confirm that exposure to UV radiation produces surface aldehyde sites that can be subsequently derivatized with amines. UV exposure using a photomask yielded sharp, well-defined micropatterned PCysMA brushes functionalized with aldehyde groups that enable conjugation to green fluorescent protein (GFP). Nanopatterned PCysMA brushes were obtained using interference lithography, and confocal microscopy again confirmed the selective conjugation of GFP. Finally, PCysMA undergoes complex base-catalyzed degradation in alkaline solution, leading to the elimination of several small molecules. However, good long-term chemical stability was observed when PCysMA brushes were immersed in aqueous solution at physiological pH.
| S-EPMC4195379 | biostudies-literature
Project description:Currently, chemotherapy is an important method for the treatment of various cancers. Nevertheless, it has many limitations, such as poor tumour selectivity and multi-drug resistance. It is necessary to improve this treatment method by incorporating a targeted drug delivery system aimed to reduce side effects and drug resistance. The present work aims to develop pH-sensitive nanocarriers containing magnetic mesoporous silica nanoparticles (MMSNs) coated with pH-responsive polymers for tumour-targeted drug delivery via the folate receptor. 2-Diethyl amino ethyl methacrylate (DEAEMA) was successfully grafted on MMSNs via surface initiated ARGET atom transfer radical polymerization (ATRP), with an average particle size of 180 nm. The end groups of poly (2-(diethylamino)ethyl methacrylate) (PDEAEMA) brushes were converted to amines, followed by a covalent bond with folic acid (FA) as a targeting agent. FA conjugated to the nanoparticle surface was confirmed by X-ray photoelectron spectroscopy (XPS). pH-Responsive behavior of PDEAEMA brushes was investigated by Dynamic Light Scattering (DLS). The nanoparticles average diameters ranged from ca. 350 nm in basic media to ca. 650 in acidic solution. Multifunctional pH-sensitive magnetic mesoporous nanoparticles were loaded with an anti-cancer drug (Doxorubicin) to investigate their capacity and long-circulation time. In a cumulative release pattern, doxorubicin (DOX) release from nano-systems was ca. 20% when the particle exposed to acidic media, compared to ca. 5% in basic media. The nano-systems have excellent biocompatibility and are minimally toxic when exposed to MCF-7, and -MCF-7 ADR cells.
| S-EPMC7795197 | biostudies-literature
Project description:In this paper; we compare double hydrophobic polystyrene-b-poly(solketal methacrylate) (PS-b-PSMA) and amphiphilic polystyrene-b-poly(glyceryl methacrylate) (PS-b-PGMA) diblock copolymer membranes which are prepared by combining the block copolymer self-assembly in solution with a non-solvent induced phase separation (SNIPS). Diblock copolymers (i.e., PS-b-PSMA) were synthesized by sequential living anionic polymerization, whereas polystyrene-b-poly(glyceryl methacrylate) (PS-b-PGMA) were obtained by acid hydrolysis of the acetonide groups of the polysolketal methacrylate (PSMA) blocks into dihydroxyl groups (PGMA). Membrane structures and bulk morphologies were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM); respectively. The resulting PS-b-PGMA diblock copolymers produce an ordered hexagonal cylindrical pore structure during the SNIPS process, while membranes fabricated from the double hydrophobic (PS-b-PSMA) do not under similar experimental conditions. Membrane performance was evaluated by water flux and contact angle measurements.
| S-EPMC6432498 | biostudies-literature
Project description:Poly(ethylene glycol) (PEG) side-chain functionalized lactide analogues have been synthesized in four steps from commercially available L-lactide. The key step in the synthesis is the 1,3-dipolar cycloaddition between PEG-azides and a highly strained spirolactide-heptene monomer, which proceeds in high conversions. The PEG-grafted lactides analogues were polymerized via ring-opening polymerization using triazacyclodecene as organocatalyst to give well-defined tri- and hepta-(ethylene glycol)-poly(lactide)s (PLA) with molecular weights above 10 kDa and polydispersity indices between 1.6 and 2.1. PEG-poly(lactide) (PLA) with PEG chain M(n) 2000 was also prepared but GPC analysis showed a bimodal profile indicating the presence of starting macromonomer. Cell adhesion assays were performed using MC3T3 E-1 osteoblast-like cells demonstrating that PEG-containing PLA reduces cell adhesion significantly when compared to unfunctionalized PLA.
| S-EPMC3263433 | biostudies-literature
Project description:Electric responsive membranes have been prepared by controlled surface grafting of poly (ionic liquid) (PIL) on the commercially available regenerated cellulose ultrafiltration membrane. The incorporation of imidazolium ring on membrane surface was evidenced by FTIR (Fourier transformed infra-red) and EDX (energy-dispersive X-ray) spectroscopy. The PIL grafting resultedin a rougher surface, reduction in pore size, and enhancement in hydrophilicity. The interaction of the electric field between the charged PIL brush and the oscillating external electric field leads to micromixing, and hence it is proposed to break the concentration polarization. This micromixing improves the antifouling properties of the responsive membranes. The local perturbation was found to decrease the water flux, while it enhanced protein rejection. At a higher frequency (1kHz) of the applied electric field, the localized heating predominates compared to micromixing. In the case of a lower frequency of the applied electric field, more perturbation can lead to less permeability, whereas it will have a better effect in breaking the concentration polarization. However, during localized heating at a higher frequency, though perturbation is less, a heating induced reduction in permeability was observed. The electric field response of the membrane was found to be reversible in nature, and hence has no memory effect.
| S-EPMC6981848 | biostudies-literature
Project description:Cellulose nanocrystals (CNCs) derived from renewable plant-based materials exhibit strong potential for improving properties of polymers by their dispersal in the polymer matrix as a composite phase. However, the hydrophilicity and low thermal stability of CNCs lead to compromised particle dispersibility in common polymers and limit the processing conditions of polymer-CNC composites, respectively. One route that has been explored is the modification of CNCs to alter surface chemistry. Acrylic materials are used in a broad class of polymers and copolymers with wide commercial applications. Yet, the available methods for adding groups that react with acrylics to enhance dispersion are quite limited. In this work, a versatile chemical modification route is described that introduces acryloyl functional groups on CNCs that can in turn be polymerized in subsequent steps to create acrylic-CNC composites. The hydroxyl group on CNC surfaces was reacted with the isocyanate moiety on 2-isocyanatoethyl methacrylate (IEM), a bifunctional molecule possessing both the isocyanate group and acryloyl group. The resulting modified CNCs (mCNCs) showed enhanced hydrophobicity and dispersibility in organic solvent relative to unmodified CNCs. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis verified the surface modification and allowed an estimation of the degree of modification as high as 0.4 (26.7% surface hydroxyl substitution CNC). The modified CNCs were copolymerized with methyl methacrylate, and the composites had improved dispersion relative to composites with unmodified CNCs and enhanced (104%) tensile strength at 2 wt % CNC when compared to the neat poly(methyl methacrylate) (PMMA), indicating a benefit of the reactive acryloyl groups added to the CNC surface. Overall, the modification strategy was successful in functionalizing CNCs, opening possibilities for their use in organic media and matrices.
| S-EPMC7726749 | biostudies-literature
Project description:Durability is a long-standing challenge in designing liquid-repellent surfaces. A high-performance omniphobic surface must robustly repel liquids, while maintaining mechanical/chemical stability. However, liquid repellency and mechanical durability are generally mutually exclusive properties for many omniphobic surfaces-improving one performance inevitably results in decreased performance in another. Here we report well-defined porous membranes for durable omniphobic surfaces inspired by the springtail cuticle. The omniphobicity is shown via an amphiphilic material micro-textured with re-entrant surface morphology; the mechanical durability arises from the interconnected microstructures. The innovative fabrication method-termed microfluidic emulsion templating-is facile, cost-effective, scalable and can precisely engineer the structural topographies. The robust omniphobic surface is expected to open up new avenues for diverse applications due to its mechanical and chemical robustness, transparency, reversible Cassie-Wenzel transition, transferability, flexibility and stretchability.
| S-EPMC5472779 | biostudies-literature
Project description:Novel anion-conductive polymers containing perfluoroalkyl and ammonium-functionalized fluorene groups were synthesized and characterized. The quaternized polymers synthesized using a dimethylaminated fluorene monomer had a well-defined chemical structure in which each fluorenyl group was substituted with two ammonium groups at specific positions. The resulting polymers had a high molecular weight (M n = 8.9-13.8 kDa, M w = 13.7-24.5 kDa) to provide bendable thin membranes with the ion-exchange capacity (IEC) ranging from 0.7 to 1.9 mequiv g-1 by solution casting. Both transmission electron microscopy images and small-angle X-ray scattering patterns suggested that the polymer membranes possessed a nanoscale phase-separated morphology based on the hydrophilic/hydrophobic differences in the polymer components. Unlike typical anion-exchange membranes found in the literature, hydroxide ion conductivity of the membranes did not increase with increasing IEC because of their high swelling capability in water. The membrane with IEC = 1.2 mequiv g-1 showed balanced properties of high hydroxide ion conductivity (81 mS cm-1 at 80 °C in water) and mechanical strength (>100% elongation and 14 MPa maximum stress at 80 °C, 60% relative humidity). The polymer main chains were stable in 4 M KOH for 1000 h, whereas the trimethylbenzyl-type ammonium groups degraded under the conditions to cause loss in the hydroxide ion conductivity. An H2/O2 fuel cell with the membrane with IEC = 1.2 mequiv g-1 exhibited a maximum power density of 242 mW cm-2 at 580 mA cm-2 current density.
| S-EPMC6644081 | biostudies-literature
Project description:We describe the use of one of the most advanced radical polymerization techniques, the reversible addition fragmentation chain transfer (RAFT) process, to produce highly functional core-shell particles based on a silica core and a shell made of functional polymeric chains with very well controlled structure. The versatility of RAFT polymerization is illustrated by the control of the polymerization of vinylbenzyl chloride (VBC), a highly functional monomer, with the aim of designing silica core-poly(VBC) shell nanoparticles. Optimal conditions for the control of VBC polymerization by RAFT are first established, followed by the use of the "grafting from" method to yield polymeric brushes that form a well-defined shell surrounding the silica core. We obtain particles that are monodisperse in size, and we demonstrate that the exceptional control over their dimensions is achieved by careful tailoring the conditions of the radical polymerization.
| S-EPMC3701384 | biostudies-literature