Functionalized nanocelluloses for biomedical applications

This doctoral thesis was prepared at the Université Grenoble Alpes under the supervision of Professor Alain Dufresne and of Julien Bras, Associate Professor HDR (Grenoble INP-Pagora / LGP2), and the co-supervision of Professor Kristin Syverud (NTNU, Norway) and of Ellinor B. Heggset, Researcher (RISE PFI, Norway).

Bastien Michel presented the results of his research entitled Cyclodextrin-functionalized nanocelluloses for biomedical applications.

Combining oxidized cellulose nanofibrils (toCNF) and various β-cyclodextrin (β-CD) derivatives makes it possible to design high-performance materials for biomedical applications. Although promising, this combination faces certain challenges, in particular the characterization of this toCNF / β-CD association. This thesis therefore consists in characterizing the phenomena of adsorption between toCNF and β-CD in order to improve the release of active ingredients which are poorly soluble in water and, consequently, to promote the antimicrobial properties of these materials.

First, the production of toCNF / β-CD materials was reported, with an investigation on the impact of various process parameters on water sorption and mechanical properties. The adsorption of β-CD was characterized via different experimental tools: it was shown that β-CD derivatives adsorb up to 10 times more onto toCNF than β-CD. The formation of an inclusion complex between a model active ingredient and the various β-CD has been characterized in depth. Finally, the functionalization of toCNF with β-CD showed improvement of the antimicrobial properties of films with increased efficiency for carboxymethylated-β-CD.

By improving knowledge of the interactions between nanocellulosic materials and different cyclodextrins, the results of this project constitute a significant step towards applications in various fields: biomedical, pollution control, etc.