New cellulose-polyacrylamide hydrogels containing nano-ceria as new promising nanocomposite materials for biomedical applications

Abstract A group of new hydrogel materials combining high physical properties and pronounced antibacterial activity has been developed. These are composite hydrogels "cellulose-polyacrylamide" based on cellulose matrices of two types: bacterial or regenerated plant cellulose. To form biologically active materials, a method of introducing ceria nanoparticles with sizes less than 5 nm was elaborated. The developed technology allows to obtain hydrogels with the content of ceria (in swollen material) up to 0.4–0.5 wt.%. Variations of the ratio of gel components concentrations, type of matrix cellulose and synthesis conditions allow to change the complex of mechanical properties of the material within a wide range, in particular, to obtain both soft, low-modular nanocomposites and hydrogels with record high rigidity. Significant differences in mechanical properties of hydrogels based on different types of cellulose fully correlate with the difference in morphological characteristics of these two groups of materials revealed by SEM. No palpable effect of nanoparticles on the morphological characteristics of the material was revealed. Both ceria nanoparticles and hydrogels containing ceria showed antibacterial activity against S.aureus ATCC 29213, S.aureus ATCC 43300, P.aeruginosa ATCC 27853, K.pneumoniae ATCC 33495. Different intensity of growth depression of the bacterial cells was determined depending on the samples composition and of the bacteria species.