RESUMO
A series of polydiacetylene (PDA) - based micelles were prepared from diacetylenic surfactant bearing polyethylene glycol, by increasing UV-irradiation times. These polymeric lipid micelles were analyzed by physicochemical methods, electron microscopy and NMR analysis. Cellular delivery of fluorescent dye suggests that adjusting the polymerization state is vital to reach the full in vitro potential of PDA-based delivery systems.
Assuntos
Sistemas de Liberação de Medicamentos , Micelas , Polietilenoglicóis/química , Polímeros/química , Poli-Inos/química , Tensoativos/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Corantes Fluorescentes/administração & dosagem , Corantes Fluorescentes/química , Células HeLa , Humanos , Oxazinas/administração & dosagem , Oxazinas/química , Polímero Poliacetilênico , Polietilenoglicóis/efeitos da radiação , Polimerização , Polímeros/efeitos da radiação , Poli-Inos/efeitos da radiação , Tensoativos/efeitos da radiação , Raios UltravioletaRESUMO
We synthesized new amphiphiles comprised of a single diacetylenic chain and an oligoethylenoxide polar chain linked by an amide bond. In aqueous medium, they are not soluble at room temperature but form weak gels. Electron microscopy studies have shown that they self-assemble into helical tapes or nanotubes with lengths of several micrometers, and inner and outer diameters of 50 ± 1 and 59 ± 1 nm, respectively. The wall has a thickness of 10 ± 1 nm for both kinds of objects and has an amphiphile bilayer structure. The hydrophobic chains are ordered, and the amide groups are linked with each other by H-bonds. The dissociation of the tubes is a first-order transition with an enthalpy of ca. 40 kJ mol(-1). The nanotubes were photopolymerized to yield purple solutions consisting of helical tapes and almost flat ribbons. The polymers exhibit irreversible thermochromism upon heating.
Assuntos
Acetileno/química , Óxido de Etileno/síntese química , Nanotubos/química , Acetileno/análogos & derivados , Amidas/química , Óxido de Etileno/química , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Tamanho da Partícula , Polimerização , Propriedades de SuperfícieRESUMO
Because they have a great propensity to aggregation in water, solubilization of carbon nanotubes (CNTs) in aqueous media remains an important challenge. Our laboratory has reported the self-organization of synthetic lipids into hemi-micellar structures at the carbon nanotubes surface. Subsequent stabilization of these carbon nanotube/lipid assembly (CNT/LA) constructs is achieved through photopolymerization of the diyne motif of the pentacosa-10,12-diynoic lipids. Herein we investigate the scope of this coating procedure for CNT solubilization. A panel of CNTs was selected according to the method of production and the characteristics of CNTs. The study revealed that it is possible to reach a complete lipid adsorption. The TEM analyses demonstrate that lipid hemi-micellar self-assemblies can be formed around SWNTs as well as around DWNTs and MWNTs, particularly for carbon nanotubes produced by the arc-discharged method. The nanotube suspensions show a very good stability and are homogeneous for months even at a high nanotubes concentration.
