Search results for "Amphiphile"

Novel, potent calmodulin antagonists derived from an all-dhexapeptide combinatorial library that inhibitin vivocell proliferation: activity and struc…

2000

: Calmodulin is known to bind to various amphipathic helical peptide sequences, and the calmodulin–peptide binding surface has been shown to be remarkably tolerant sterically. d-Amino acid peptides, therefore, represent potential non-hydrolysable intracellular antagonists of calmodulin. In the present study, synthetic combinatorial libraries have been used to develop novel d-amino acid hexapeptide antagonists to calmodulin-regulated phosphodiesterase activity. Five hexapeptides were identified from a library containing over 52 million sequences. These peptides inhibited cell proliferation both in cell culture using normal rat kidney cells and by injection via the femoral vein following part…

Structure and luminescence properties of supramolecular polymers of amphiphilic aromatic thioether–peptide conjugates in water

2019

We present the preparation of luminophore–peptide conjugates that self-assemble into supramolecular polymers in neutral buffer. To this end, we have prepared a small library of six conjugates with varying substitution patterns of the aromatic thioethers, as well as varying amino acid sequences. The latter have allowed us to tune the thermodynamic driving force for self-assembly and probe their photoluminescent properties either in the monomeric or polymeric state, while fully avoiding selective solvent techniques or organic solvent mixtures. All of the supramolecular structures were characterised with transmission electron microscopy, circular dichroism measurements, as well as steady-state…

Amphiphilic derivatives of a polyaspartamide: their aggregation and solubilization ability

2006

Abstract The self-aggregation and solubilization capability of a series of amphiphilic copolymers obtained by derivatisation of polymeric chain of α,β-poly(N-2-hydroxyethyl)- dl -aspartamide (PHEA) with polyethylene glycols (PEG, being different molecular weight 2000 or 5000 Da, PEG2000 and PEG5000, respectively) and/or hexadecylamine alkyl chain (C16), namely PHEA–PEG2000, PHEA–PEG5000, PHEA–C16, PHEA–PEG2000–C16 and PHEA–PEG5000–C16, have been evidenced by performing systematic tensiometric and spectrophotometric studies. All measurements have been performed at 25.0 °C over a wide copolymer concentration range. The tensiometric results have shown that, for all copolymers studied, the surf…

Dye loading of amphiphilic poly(organosiloxane) nanoparticles.

2003

Cyclodextrin/surfactant inclusion complexes: An integrated view of their thermodynamic and structural properties

2021

Cyclodextrins (CDs) play an important role in self-assembly systems of amphiphiles. The structure of CDs provides distinguished physicochemical properties, including the ability to form host-guest complexes. The complexation affects the properties of guest molecules and can produce supramolecular aggregates with desirable characteristics for fundamental and practical applications. Surfactants are particularly attractive host molecules due to their wide variety, availability, responsiveness to different stimuli, and high relevance in different fields, e.g. medical, cosmetic, pharmaceutical, and food industries. The tendency of organization in higher-order supramolecular aggregates arises the…

Thin Amphiphilic Polymer-Capped Upconversion Nanoparticles: Enhanced Emission and Thermoresponsive Properties

2014

Upconversion nanoparticles (ß-NaYF4:Er3+, Yb3+, UCNPs) were capped with a thin polymer shell by replacing the oleate ligand of hydrophobic UCNPs by multidentate thiolate-grafting of P(MEO2MA-co-SEMA) copolymers. The presence of the 2-(2-methoxyethoxy)ethyl side chains of MEO2MA extending out of the nanohybrid made them water-dispersible. The UCNP@P(MEO2MA-co-SEMA) nanohybrids exhibited an enhanced emission by up to a factor of 10, as compared with that of their hydrophobic precursor in dichloromethane and even in water (a factor of 2). Moreover, their thermoresponsiveness was modulated by the pH; this is consistent with the presence of some thiol groups at the nanohybrid periphery. Remarkab…

Efficiency Boosting of Surfactants with Poly(ethylene oxide)-Poly(alkyl glycidyl ether)s: A New Class of Amphiphilic Polymers

2020

Twenty years ago, it was found that adding small amounts of amphiphilic block copolymers like poly(ethylene propylene)-co-poly(ethylene oxide) (PEP-b-PEO) to microemulsion systems strongly increases the efficiency of medium-chain surfactants to solubilize water and oil. Although being predestined to serve as a milestone in microemulsion research, the effect has only scarcely found its way into applications. In this work, we propose new types of efficiency boosters, namely, poly(ethylene oxide)-poly(alkyl glycidyl ether carbonate)s (PEO-b-PAlkGE) and their "carbonated" poly(ethylene oxide)-poly(carbonate alkyl glycidyl ether) analogs. Their synthesis via anionic ring-opening polymerization (…

Peptide–Membrane Interactions Monitored by Fluorescence Lifetime Imaging: A Study Case of Transportan 10

2021

The interest on detailed analysis of peptide-membrane interactions is of great interest in both fundamental and applied sciences as these may relate to both functional and pathogenic events. Such interactions are highly dynamic and spatially heterogeneous, making the investigation of the associated phenomena highly complex. The specific properties of membranes and peptide structural details, together with environmental conditions, may determine different events at the membrane interface, which will drive the fate of the peptide-membrane system. Here, we use an experimental approach based on the combination of spectroscopy and fluorescence microscopy methods to characterize the interactions …

(1-Adamantyl)methyl glycidyl ether: a versatile building block for living polymerization.

2014

(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST). Additionally, AdaGE is utilized as a termination agent in carbanionic polymerization, affording adamantyl-terminated polymers. Using these structures as macroinitiators fo…

Design and evaluation of sensory systems based on amphiphilic anthraquinones molecular receptors

2015

A new paradigm is described that allows one to create different types of sensors: from highly sensitive ones to practical household devices. Our approach relies on modular molecular receptors incorporating an intensely-colored aminoanthraquinone signaling unit equipped with both hydrophilic and hydrophobic modules, the number and size of which being configured in accordance with the targeted analyte and the sought detection method. An important advantage is the compliance with some principles of green chemistry, avoiding the use of toxic organic solvents. The proper functionalization of the anthraquinone scaffold afforded water-soluble chromoinophores capable of quantifying selectively Hg2+…