Search results for "Amphiphile"
showing 10 items of 270 documents
Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends
2018
This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), inst…
Tamoxifen-loaded polymeric micelles: preparation, physico-chemical characterization and in vitro evaluation studies.
2004
Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA-PEG-C(16) and PHEA-C(16)) and containing different amount of Tamoxifen, were prepared. All Tamoxifen-loaded polymeric micelles showed to increase drug water solubility. TEM studies provided evidence of the formation of supramolecular core/shell architectures containing drug, in the nanoscopic range and with spherical shape. Samples with different amount of encapsulated Tamoxifen were subjected to in vitro cytotoxic studies in order to evaluate the effect of Tamoxifen micellization on cell growth inhibition. All samples of T…
Hyaluronic acid dressing of Hydrophobic Carbon Nanodots: a Self-assembling Strategy of Hybrid Nanocomposites with Theranostic Potential
2021
We propose a rational design of hyaluronic acid-dressed red-emissive carbon dots (CDs), with a well-structured hydrophobic core capable of locally delivering high amount doxorubicin (Doxo) (> 9% w/w) and heat (hyperthermia) in a light stimuli sensitive fashion. We combined in a unique micelle-like superstructure the peculiar optical properties of CDs (NIR photothermal conversion and red fluorescence) with the ability of hyaluronic acid (HA) shell of stabilizing nanomedicines in aqueous environment and recognizing cancer cells overexpressing CD44 receptors on their membranes, thus giving rise to smart theranostic agents useful in cancer imaging and NIR-triggered chemo-phototherapy of solid t…
Acid‐Labile Amphiphilic PEO‐ b ‐PPO‐ b ‐PEO Copolymers: Degradable Poloxamer Analogs
2016
Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molec…
Amphiphilic Copolymers Based on Poly[(hydroxyethyl)-d,l-aspartamide]: A Suitable Functional Coating for Biocompatible Gold Nanostars
2013
Novel amphiphilic copolymers have been synthesized based on a biocompatible poly(hydroxyethylaspartamide) (PHEA) backbone, bearing both anchoring groups for gold nanoparticles, such as thiols and disulfide, and conjugable moieties, such as amino groups, the latter as points suitable for appending further functional agents. The strategy was to functionalize α,β-poly[(N-2- hydroxyethyl)-d,l-aspartamide] (PHEA) with PEG2000-NH2 and with ethylenediamine (EDA) obtaining a partially pegylated copolymer with a large number of pendant primary amino groups. A fraction of the latter was conjugated with molecules bearing terminal thiol moieties such as 12-mercaptododecanoic acid (MDA) and disulfide gr…
Polypeptoid-block-polypeptide Copolymers: Synthesis, Characterization, and Application of Amphiphilic Block Copolypept(o)ides in Drug Formulations an…
2013
We report the synthesis of polysarcosine-block-polyglutamic acid benzylester (PSar-block-PGlu(OBn)) and polysarcosine-block-polylysine-ε-N-benzyloxycarbonyl (PSar-block-PLys(Z)) copolymers. The novel polypeptoid-block-polypeptide copolymers (Copolypept(o)ides) have been synthesized by ring-opening polymerization (ROP) of N-carboxyanhydrides (NCAs). Polymerization conditions were optimized regarding protecting groups, block sequence and length. While the degree of polymerization of the PSar block length was set to be around 200 or 400, PGlu(OBn) and PLys(Z) block lengths were varied between 20 to 75. The obtained block copolymers had a total degree of polymerization of 220-475 and dispersity…
Supramolecular Assemblies Based on Complexes of Nonionic Amphiphilic Cyclodextrins and a meso-Tetra(4- sulfonatophenyl)porphine Tributyltin(IV) Deriv…
2013
Amphiphilic cyclodextrin (ACyD) provides water-soluble and adaptable nanovectors by modulating the balance between the hydrophobic and hydrophilic chains at both CyD sides. This work aimed to design nanoassemblies based on nonionic and hydrophilic ACyD (SC6OH) for the delivery of a poor-water-soluble organotin(IV)-porphyrin derivative [(Bu3Sn)4TPPS] to melanoma cancer cells. To characterize the porphyrin derivatives under simulated physiological conditions, a speciation was performed using complementary techniques. In aqueous solution (≤ 20 μM), (Bu3Sn)4TPPS primarily exists as a monomer (2 in Figure 1), as suggested by the low static anisotropy (ρ ≈ 0.02) with a negligible formation of por…
Monolayers of rod-shaped and disc-shaped liquid crystalline compounds at the air-water interface
2008
Calamitic (rod-shaped) and discotic (disc-shaped) thermotropic liquid crystalline (LC) compounds were spread at the air-water interface, and their ability to form monolayers was studied. The calamitic LCs investigated were found to form monolayers which behave analogously to conventional amphiphiles such as fatty acids. The spreading of the discotic LCs produced monolayers as well, but with a behaviour different from classical amphiphiles. The areas occupied per molecule are too small to allow the contact of all hydrophilic groups with the water surface and the packing of all hydrophobic chains. Various molecular arrangements of the discotics at the water surface to fit the spreading data a…
Amphiphilic dyes for NLO in LB-films
1991
The influence of structural variations of phenyl-hydrazones and stilbazium salts on monolayer behaviour and second-harmonic generation in LB-monolayers is discussed. In contrast to the stilbazium salts the variation of the substituents of the phenylhydrazones does not influence the absorption maximum of the dyes in resonance enhancement of the nonlinearity. This allows a direct comparison of the substitution pattern on SHG.
Polyvinylferrocene-Based Amphiphilic Block Copolymers Featuring Functional Junction Points for Cross-Linked Micelles
2016
The synthesis of high-molecular-weight, well-defined poly(vinylferrocene)-block-poly(ethylene glycol) (PVFc-b-PEG) diblock copolymers (Mn = 13 000–44 000 g mol–1; Đ = 1.29–1.34) with precisely one allyl group at the junction point is introduced. Allyl glycidyl ether (AGE) was used to end-functionalize PVFc, resulting in hydroxyl functional macroinitiators for the oxyanionic polymerization of ethylene oxide. The self-assembly behavior of the amphiphilic PVFc-b-PEG copolymers in water has been investigated in a detailed manner, using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The redox activity of the PVFc block was confirmed by UV/vis spectroscopy, while cyclo…