National Nano-sized protein carriers from polysaccharides bear a lot of potential
because they are made of non toxic materials from biomass, via energy efficient
and environment friendly processes. Particularly attractive for the production of safe
delivery systems is the formation of colloidal polyelectrolyte complexes by charge
neutralization between oppositely charged polysaccharides, which takes place in water at
room temperature, under moderate stirring, in the absence of any chemical cross-linker
But more criteria are to be met to produce nano-sized delivery systems for in vivo use:
these carriers should maintain their colloidal properties at physiological pH and salt
concentration have a long shelf life and be lyophilized and sterilized.
Our strategy towards colloids meeting the above specifications was based on the use of
chitosan, a copolymer of N-acetyl glucosamine and glucosamine, obtained from partial
deacetylation of chitin. Chitosan is known for its biocompatibility. Dextran sulfate was
selected as polyanion.
We will address some formulation issues like the mode and the order of addition of
the reactants and more fundamental aspects such as the impact of chitosan intrinsic
parameters (molar mass and the degree of acetylation i.e. the molar fraction of N-acetyl
groups in the polymer chain) on the particle size, size distribution, the colloidal stability
in physiological media and the capacity of lyophilisation.
Results on the association with proteins or fluorescent markers and preliminary results
on the effective delivery of vaccine in vivo will be reported
Thierry Delair has been a full professor at Lyon University, since November 2008. Before he spent
twenty years in different R&D departments in bioM?rieux, a major French biotech company, where
he developed polymers for medical diagnostics and vaccine delivery.He co-authored 121 articles,
17 patents, 8 book chapters, and gave 60 oral conferences. His areas of expertise are the physico-
chemistry of dispersed media, natural polymer formulation, polymers / biological molecules interactions.
His current research subjects are focused on the elaboration and the characterization of nano-structured
physical hydrogels based on polysaccharides originated from biomass, for tissue engineering, drug and
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