Bisnorcymserine

Tissue engineering, particularly leveraging three-dimensional (3D) bioprinting, is emerging as a transformative solution to repair critical-size bone defects. However, identifying suitable biomaterials remains a key technological bottleneck in the field. Toward this broader goal, this study explored a composite bioink containing photocurable silk fibroin (SF) and bacterial nanocellulose (BNC) for fabricating scaffolds for bone tissue engineering (BTE) by 3D bioprinting using digital light projection (DLP). We prepared scaffolds with 0, 0.25, and 0.75 wt% BNC and characterized their physicochemical properties (degradation, viscoelasticity, porosity, compressive strength). We assessed samples in simulated body fluid (SBF) after 14 days to evaluate biomineralization. Additionally, using MC3T3-E1 preosteoblast cells, we examined cell viability, metabolic activity, proliferation, and osteogenic potential through alkaline phosphatase (ALP), Alizarin Red S (ARS), von Kossa, hematoxylin and eosin (H&E), and Picrosirius Red assays. The optimized bioinks produced hydrogels with controlled degradation, tunable viscoelasticity, interconnected pores, and significantly improved compressive strength. Specifically, 10 % methacrylated-silk with 0.75 % BNC (Silk-MA/0.75BNC) showed superior mechanical properties compared to 10 % Silk-MA or 10 % Silk-MA with 0.25 % BNC (Silk-MA/0.25BNC). In vitro studies confirmed enhanced biomineralization with Silk-MA/0.75BNC, increased calcium deposits, and improved cell viability and metabolic activity with BNC incorporation. Hence, the 3D-bioprinted composite scaffolds were shown to effectively support cell proliferation, with the 0.75 % BNC bioink significantly stimulating osteogenic markers. These results underscore the potential of Silk-MA/BNC composite bioinks for advanced 3D bioprinting of BTE constructs.

Bacterial nanocellulose (BNC) has many advantageous physicochemical characteristics, including high mechanical strength, high porosity, excellent water adsorption, and biocompatibility, making it a promising option for a wide range of biomedical applications. However, the limited biodegradability of BNC within the human body could reduce its utility in this field. In the present study, we investigated the in vitro biodegradability of a BNC composite of bacterial nanocellulose-chitosan-alginate-gelatin (BNC-CS-AG-GT). This BNC-CS-AG-GT hydrogel scaffold was shown to be gradually degraded during immersion in simulated body fluid (SBF) with the addition of lysozyme. Furthermore, the compressive strength of the BNC-CS-AG-GT hydrogel slowly decreased in correlation with incubation time: by 8 weeks of incubation in SBF, the compressive strength was reduced from ∼68 to ∼25 MPa, coupled with a 54% weight reduction. In cell culture, the BNC-CS-AG-GT scaffold was noncytotoxic. Cultivation of osteogenic MC3T3-E1 cells in osteogenic medium within a BNC-CS-AG-GT hydrogel for 4 weeks showed that the BNC-CS-AG-GT hydrogel supports cell adhesion and cell proliferation and promotes alkaline phosphatase (ALP) activity and mineralization in vitro. Moreover, BNC-CS-AG-GT exhibited strong antibacterial properties. The favorable biodegradability, mechanical properties, biocompatibility, and antibacterial activity of the BNC-CS-AG-GT hydrogel scaffold indicate that it has potential as a promising candidate for applications in bone tissue engineering. However, although these findings suggest that BNC-CS-AG-GT hydrogels have osteogenic potential in vitro, future additional studies in vivo and extended osteogenic differentiation assays are required to confirm the efficacy of BNC-CS-AG-GT scaffolds under physiological load conditions.