Miscellaneous nanoaggregates made of beta-CD esters synthesised by an enzymatic pathway

Various beta-cyclodextrin (beta-CD) fatty esters with different chain lengths (C4-C14) were synthesised by transesterification of beta-cyclodextrin by vinyl fatty ester using thermolysin in DMSO. For each cyclodextrin derivatives, two batches of synthesis were realized. The ability of these derivatives to form nano-organized systems was investigated through the solvent displacement technique. During the formulation step, the effects of the initial concentration of beta-CD fatty esters in the organic phase and that of the final volume of the aqueous non-solvent phase were studied. Except for the beta-CD C4 ester, the transesterified beta-CD derivatives led to measurable nanoparticles. Cryo-electron microscopy images showed a significant morphological variability. Spherical, rod-like or more irregularly-shaped nano-objects were observed with either matricial or lamellar structures. A statistical analysis by a two-way ANOVA was computed for each class of beta-cyclodextrin esters in order to determine the effects of batch and formulation on the final size of nanoparticles.