Biomedical subjects

Y Gnanou

Publications and source records attributed to Y Gnanou.

4 recordsLinked to original sources

PubMed2006

Amphiphilic diblock copolymers with adhesive properties: I. Structure and swelling with water.

We study asymmetric block copolymers with the simple diblock AB architecture, in the case where the longer block A is both hydrophobic and "soft", whereas the shorter block B is hydrophilic and "hard". Materials with such a particular combination of physico-chemical and mechanical properties have distinctive advantages, in particular for designing water-compatible adhesive materials. The phase diagram is established, combining NMR and SAXS characterisations of the materials. The swelling with water is monitored through gravimetry and "time-resolved" SAXS. Indications of maintained adhesive properties in a wet environment are given.

Journal Article↗

PubMed2006

pH-responsive micelles and vesicles nanocapsules based on polypeptide diblock copolymers.

The self-assembly of well-defined polypeptide-based diblock copolymers into micelles and vesicles is presented. The stimuli-responsive behavior of polypeptides to pH and ionic strength is used to produce stimuli-responsive nanoparticles with controlled size and shape. Results focusing on micelles and vesicles obtained from polypeptide-based diblock copolymers that are particularly promising for biomedical applications are detailed by means of static and dynamic light scattering analysis, UV circular dichroism, NMR and small angle neutron scattering experiments. Also systems able to form vesicles with a narrow size distribution at basic and acid pH going through a single molecule intermediate state are presented. These nanoparticles are particularly interesting for encapsulation and delivery purpose at a controlled pH.

Capsules↗

PubMed2003

From supramolecular polymersomes to stimuli-responsive nano-capsules based on poly(diene-b-peptide) diblock copolymers.

This paper discusses the self-assembly of block copolymers into vesicular morphology. After a brief state of art of the field, a system based on an amphiphilic poly(butadiene)- b-poly(-L-glutamic acid) (PB- b-PGA) diblock copolymer in aqueous solution is discussed in detail. The aggregation behavior of this block copolymer has been investigated by means of fluorescence spectroscopy, dynamic (DLS) and static (SLS) light scattering as well as transmission electron microscopy (TEM). The diblock copolymer was found to form well-defined vesicles in water. The size of these so-called polymersomes or peptosomes could be reversibly manipulated as a function of both pH and ion strength. Depending on the pH of the aqueous solution, the hydrodynamic radii of these vesicles were found to vary from 100 nm to 150 nm. By cross-linking the 1,2-vinyl double bonds present in the polybutadiene block, the ability to transform a transient supramolecular self-organized aggregate into a permanent "shape-persistent stimuli-responsive nanoparticle" has been demonstrated.

Butadienes↗

PubMed2001

Synthesis and characterization of linear, hyperbranched, and dendrimer-like polymers constituted of the same repeating unit.

The synthesis of a linear polymer that includes both P=N and P=S double bonds, and P-O and P-C single bonds is reported by using two different paths that involve deprotection reactions and the Staudinger reaction. The preparation of hyperbranched polymers made up of OC6H4P(Ph)2=N-P=S repeating units is also described. Five generations of dendrimers originating from the same building blocks were prepared. The characterisation of all these phosphorus-based macromolecular architectures (solution behaviour, size exclusion chromatography, intrinsic viscosity, thermal behaviour) revealed marked differences in their respective behaviour.

Journal Article↗