Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one... more Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one or two PCL blocks were obtained via coordinated anionic polymerization of ε-caprolactone by using hydroxy terminated PDMS oligomers both as initiators and comonomers. Molecular weights of these copolymers were varied over a wide range between 7200 and 30400 g/mol and the formation of copolymers with desired backbone composition were monitored by 1H NMR spectroscopy and SEC. DSC studies illustrated the formation of two phase morphologies, with PDMS and PCL transitions respectively and the influence of the copolymers structure on their thermal properties has been examined.
Abstract We report the preparation of microporous surfaces prepared from immiscible polymer blend... more Abstract We report the preparation of microporous surfaces prepared from immiscible polymer blends using the Breath Figures methodology. The selected polymer blend is formed by two biodegradable polymers i.e. poly(e-caprolactone) and poly(lactic acid) both known to be biocompatible and presenting two distinct kinetics of biodegradation. These two polymers form immiscible polymer blends upon solvent casting in low relative humidity conditions. However, when quenching the melt using fast cooling processes or by evaporation in a moist atmosphere, micrometer size phase-separated domains have been clearly identified by Raman Confocal. This allowed us to analyze cell adhesion as well as proliferation on both planar (those obtained from melt quenching) and microporous surfaces (those obtained by the breath figures approach) formed from different blend compositions. Using C166-GFP and RAW264.7 cell types as a model we could observe an improved adhesion of the C166-GFP on top of the microporous surfaces evidencing the role of the surface topography on the cell adhesion process. In addition, preliminary results on the RAW264.7 cell adhesion indicated the polarization to M2 phenotypes instead of M1 which is a pre-requisite for the potential use of this material for implantology purposes.
Http Dx Doi Org 10 1080 00218464 2013 757521, Feb 12, 2013
ABSTRACT The present paper focuses on a simplified method to study the orientation and the anisot... more ABSTRACT The present paper focuses on a simplified method to study the orientation and the anisotropy of two different alkanethiols self-assembled monolayers on gold surfaces. The alkanethiols of interest vary only by their terminal functionalities (COOH and COOCH3), thus allowing one to highlight the influence of these ending chemical groups on the final orientation of the adsorbed molecules. 11-Mercaptoundecanoic acid [HS-(CH2)10-COOH] and the methyl-11-mercaptoundecanoate [HS-(CH2)10-COOCH3] were grafted under adequate conditions to obtain a high grafting density on gold substrates. These latter, before and after the alkanethiol adsorption, were analyzed mainly by the polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) technique to access orientation angles, and by atomic force microscopy (AFM) to check the homogeneity of the grafted layer. By applying an original PM-IRRAS simplified method, the results showed an orientation closer to the normal of the surface plane in the case of the acid thiol compared with the ester one, which is probably because of the lateral hydrogen bonds established between the adjacent COOH functions. This method offers a direct and simple way to quantify the orientation angles in the alkanethiol nanofilms.
Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one... more Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one or two PCL blocks were obtained via coordinated anionic polymerization of ε-caprolactone by using hydroxy terminated PDMS oligomers both as initiators and comonomers. ...
We report the preparation of microporous functional polymer surfaces that have been proven to be ... more We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties.
Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one... more Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one or two PCL blocks were obtained via coordinated anionic polymerization of ε-caprolactone by using hydroxy terminated PDMS oligomers both as initiators and comonomers. Molecular weights of these copolymers were varied over a wide range between 7200 and 30400 g/mol and the formation of copolymers with desired backbone composition were monitored by 1H NMR spectroscopy and SEC. DSC studies illustrated the formation of two phase morphologies, with PDMS and PCL transitions respectively and the influence of the copolymers structure on their thermal properties has been examined.
Abstract We report the preparation of microporous surfaces prepared from immiscible polymer blend... more Abstract We report the preparation of microporous surfaces prepared from immiscible polymer blends using the Breath Figures methodology. The selected polymer blend is formed by two biodegradable polymers i.e. poly(e-caprolactone) and poly(lactic acid) both known to be biocompatible and presenting two distinct kinetics of biodegradation. These two polymers form immiscible polymer blends upon solvent casting in low relative humidity conditions. However, when quenching the melt using fast cooling processes or by evaporation in a moist atmosphere, micrometer size phase-separated domains have been clearly identified by Raman Confocal. This allowed us to analyze cell adhesion as well as proliferation on both planar (those obtained from melt quenching) and microporous surfaces (those obtained by the breath figures approach) formed from different blend compositions. Using C166-GFP and RAW264.7 cell types as a model we could observe an improved adhesion of the C166-GFP on top of the microporous surfaces evidencing the role of the surface topography on the cell adhesion process. In addition, preliminary results on the RAW264.7 cell adhesion indicated the polarization to M2 phenotypes instead of M1 which is a pre-requisite for the potential use of this material for implantology purposes.
Http Dx Doi Org 10 1080 00218464 2013 757521, Feb 12, 2013
ABSTRACT The present paper focuses on a simplified method to study the orientation and the anisot... more ABSTRACT The present paper focuses on a simplified method to study the orientation and the anisotropy of two different alkanethiols self-assembled monolayers on gold surfaces. The alkanethiols of interest vary only by their terminal functionalities (COOH and COOCH3), thus allowing one to highlight the influence of these ending chemical groups on the final orientation of the adsorbed molecules. 11-Mercaptoundecanoic acid [HS-(CH2)10-COOH] and the methyl-11-mercaptoundecanoate [HS-(CH2)10-COOCH3] were grafted under adequate conditions to obtain a high grafting density on gold substrates. These latter, before and after the alkanethiol adsorption, were analyzed mainly by the polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) technique to access orientation angles, and by atomic force microscopy (AFM) to check the homogeneity of the grafted layer. By applying an original PM-IRRAS simplified method, the results showed an orientation closer to the normal of the surface plane in the case of the acid thiol compared with the ester one, which is probably because of the lateral hydrogen bonds established between the adjacent COOH functions. This method offers a direct and simple way to quantify the orientation angles in the alkanethiol nanofilms.
Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one... more Well-defined block poly(ε-caprolactone)-b-poly(dimethylsiloxane) (PCL-b-PDMS) copolymers with one or two PCL blocks were obtained via coordinated anionic polymerization of ε-caprolactone by using hydroxy terminated PDMS oligomers both as initiators and comonomers. ...
We report the preparation of microporous functional polymer surfaces that have been proven to be ... more We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties.
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Papers by Tamara Elzein