Novel Acryloylated and Methacryloylated Nanocellulose Derivatives with Improved Mucoadhesive Properties

In this work, three nanocellulose derivatives are synthesized with the aim of preparing new mucoadhesive materials. Nanocellulose is reacted with glycidyl methacrylate in dimethylsulphoxide, and with acryloyl and methacryloyl chloride in dimethylacetamide in the presence of 4-(N,N-dimethylamino)pyridine as a catalyst. These reactions are carried out under heterogeneous conditions, and the reaction products are characterized using various spectroscopic techniques, X-ray diffraction, atomic force microscopy, and thermogravimetric analysis. The Fourier-transform infrared spectra showed all the characteristic absorption bands typical for cellulose and also new peaks at 1720 cm^-1 for the carbonyl group (C═O) and 1639, 812 cm^-1 for the double bond (C═C). It is established that the crystal structure of the nanocellulose is slightly changed with derivatisation and the thermal stability of these derivatives increased. Mucoadhesive properties of nanocellulose and its derivatives is evaluated using the tensile test, rotating basket method, and fluorescence flow-through method. The retention of these polymers is evaluated on sheep oral mucosal tissue ex vivo using artificial saliva. Test results demonstrated that the new derivatives of nanocellulose have improved mucoadhesive properties compared to the parent nanocellulose.