Cholesterol (Ch) linked to a linear-hyperbranched block copolymer composed of poly(ethylene glycol) (PEG) and poly(glycerol) (hbPG) was investigated for its membrane anchoring properties. Two polyether-based linear-hyperbranched block copolymers with and without a covalently attached rhodamine fluorescence label (Rho) were employed (Ch-PEG30-b-hbPG23 and Ch-PEG30-b-hbPG17-Rho). Compression isotherms of co-spread 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with the respective polymers were measured on the Langmuir trough and the morphology development of the liquid-condensed (LC) domains was studied by epi-fluorescence microscopy. LC domains were strongly deformed due to the localization of the polymers at the domain interface, indicating a line activity for both block copolymers. Simultaneously, it was observed that the presence of the fluorescence label significantly influences the domain morphology, the rhodamine labelled polymer showing higher line activity. Adsorption isotherms of the polymers to the water surface or to monolayers of DPPC and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), respectively, were collected. Again the rhodamine labelled polymer showed higher surface activity and a higher affinity for insertion into lipid monolayers, which was negligibly affected when the sub-phase was changed to aqueous sodium chloride solution or phosphate buffer. Calorimetric investigations in bulk confirmed the results found using tensiometry. Confocal laser scanning microscopy (CLSM) of giant unilamellar vesicles (GUVs) also confirmed the polymers' fast adsorption to and insertion into phospholipid membranes.
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http://dx.doi.org/10.1039/c5sm01017a | DOI Listing |
Macromolecules
June 2024
Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Topology significantly impacts polymer properties and applications. Hyperbranched polymers (HBPs) synthesized via atom transfer radical polymerization (ATRP) using inimers typically exhibit broad molecular weight distributions and limited control over branching. Alternatively, copolymerization of inibramers (IB), such as α-chloro/bromo acrylates with vinyl monomers, yields HBPs with precise and uniform branching.
View Article and Find Full Text PDFBiomater Sci
April 2022
Laboratorio di Scienza dei Materiali e Nanotecnologie (LMNT), CR-INSTM, Dipartimento di Science Biomediche, Chirurgiche e Sperimentali, Viale S. Pietro, 07100 Sassari, Italy.
The outbreak of the Covid-19 pandemic due to the SARS-CoV-2 coronavirus has accelerated the search for innovative antivirals with possibly broad-spectrum efficacy. One of the possible strategies is to inhibit the replication of the virus by preventing or limiting its entry into the cells. Nanomaterials derived from lysine, an essential amino acid capable of forming homopeptides of different shapes and sizes through thermal polymerization, are an exciting antiviral option.
View Article and Find Full Text PDFJ Am Chem Soc
November 2021
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China.
Organosilicon compounds and polymers have found wide applications as synthetic building blocks and functional materials. Hydrosilylation is a common strategy toward the synthesis of organosilicon compounds and polymers. Although transition-metal-catalyzed hydrosilylation has achieved great advances, the metal-free hydrosilylation polymerization of dienes and bis(silane)s, especially the one suitable for both electron-rich and electron-deficient dienes, is largely lacking.
View Article and Find Full Text PDFA new synthetic strategy for the preparation of macromolecular MRI contrast agents (CAs) is reported. Four gadolinium(iii) complexes bearing either one or two polymerizable methacrylamide groups were synthesized, serving as monomers or crosslinkers for the preparation of water-soluble, polymeric CAs using Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. Using this approach, macromolecular CAs were synthesized with different architectures, including linear, hyperbranched polymers and gels.
View Article and Find Full Text PDFBiomacromolecules
February 2019
Department of Chemistry , State University of New York-ESF, Syracuse , New York 13210 , United States.
This study describes the first use of laccase-lipase enzymatic reaction for the synthesis of novel perfectly structured alternating copolymers. Initially, six types of complexing agents, linear-linear, linear-linear-linear, linear-dendritic, dendritic-linear-dendritic, linear-hyperbranched, and hyperbranched-linear-hyperbranched amphiphilic block copolymers, are proven to significantly enhance enzyme activity of three different types of lipases - Penicillium camemberti, Candida rugosa, and Burkholderia cepacia (up to 1400%, 1700%, and 870% increase with respect to the native enzymes). The copolymerization is performed in several consecutive steps: (a) lipase and laccase are dissolved in aqueous medium at neutral pH; (b) a complexing agent is added leading to cocompartmentalization of the two enzymes within a micelle or physical network; (c) the two comonomers are introduced simultaneously to the tandem enzyme complex.
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