Investigation of bacterial nanocellulose/calcium phosphates-based composite containing cerium for bone repair

Bacterial nanocellulose (BNC) has attracted considerable attention in the field of biomedical engineering due to its potential for use in bone regeneration applications. The present study investigates the in vitro and in vivo efficacy of bacterial nanocellulose (BNC) combined with calcium and cerium ions (BNC-Ce:CaP) in bone regeneration applications. XRD analysis confirmed the presence of monetite and hydroxyapatite phases in BNC-CaP, while BNC-Ce:CaP revealed an additional brushite phase. Based on XPS analysis, cerium (III) is found in BNC-Ce:CaP at a concentration of 4.14 % (mol/mol). BNC revealed ultrafine 3D nanofibers with diameters ranging from 20.8 to 53.0 nm, while BNC-Ce:CaP composite, containing cerium, exhibited urchin-like structures with diameters around 1 µm and BNC-CaP composite presented phosphates covering the fiber surfaces, leading to significant thickness increases and pleat formation (70-180 nm). The composite materials demonstrated insignificant cytotoxicity. The results performed by histomorphometric analysis demonstrated that the BNC-Ce:CaP composites showed superior mineralized tissue formation after 60 days. Gene expression revealed a reduction in the inflammatory response and an increase in the expression of osteogenic markers, such as Bmp-2 and Osterix, in addition to an increase in the expression of angiogenic genes, such as Vegf. These findings highlight the potential of BNC-Ce:CaP composites as effective barriers to promote bone regeneration.