Abstract

The goal of this work was to develop an in vitro model of the plant primary cell wall. A bottom up approach was chosen for the rational design of 2D and 3D constructs made of a lipid membrane, cellulose nano crystals (CNCs) and xyloglucan (XG). First, the interaction between the building blocks was probed using light scattering, isothermal titration calorimetry, quartz crystal microbalance and electron microscopy, revealing firstly the electrostatic nature of the interaction between CNCs and a lipidic membrane and secondly, specific interaction between CNCs and XG in a precise stoichiometric ratio. Then, the optimal parameters from the interaction studies were used to obtain 2D and 3D structures by depositing alternating layers of CNCs and XG on flat substrates (multilayered films) and giant unilamellar vesicles (GUVs). A linear growth of the films was revealed by atomic force microscopy (AFM) experiments while the response of decorated vesicles to osmotic shocks lead to their buckling due to the rigidification of the lipid membrane. Finally, the mechanical properties of the constructs were characterized using AFM indentation, revealing a Young's modulus of few hundred kPa, similarly to what is observed for real plant cell walls.

Key words: primary cell wall, lipid membranes, cellulose, interaction, biomimetics