AbstractNanofiber alignment in tissue engineering scaffolds is a crucial factor controlling the cell behavior. In this work, we report a facile approach to obtain aligned nanofibers of bacterial cellulose (BC) by forcing the culture medium of bacteria to flow along a fixed direction. The emphasis of this work was placed on the effect of flowing velocity on the alignment of the as-prepared oriented BC (OBC). X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses indicated that the velocity affected the crystallinity and thermal stability of BC while the chemical structure did not change with the velocity. The controllable alignment of BC nanofibers makes them a promising material for the construction of biomimetic scaffolds for tissue engineering and regenerative medicine.
Three-dimensional nanofibrous scaffolds that morphologically mimic natural extracellular matrices hold great promises in tissue engineering and regenerative medicine due to their increased cell attachment and differentiation compared with block structure. In this work, for the first time, three-dimensional porous nanofibrous 58S bioglass scaffolds have been fabricated using a sacrificial template method. During the process, a natural three-dimensional nanofibrous bacterial cellulose was used as the sacrificial template on which precursor 58S glass was deposited via a sol-gel route. SEM and TEM results verify that the as-prepared 58S scaffolds can inherit the three-dimensional nanofibrous feature of bacterial cellulose. Pore structure characterizations by nitrogen adsorption-desorption and mercury intrusion porosimetry demonstrate that the 58S scaffolds are highly porous with a porosity of 75.1% and contain both mesopores (39.4 nm) and macropores (60 µm) as well as large BET surface area (127.4 m g). In vitro cell studies suggest that the 58S scaffold is bioactive and biocompatible with primary mouse osteoblast cells, suggesting that the nanofibrous structure of 58S is able to provide an appropriate environment for cellular functioning. These results strongly suggest that the three-dimensional nanofibrous 58S scaffold has great potential for application in bone tissue engineering and regenerative medicine.
Developing fibrous scaffolds with hierarchical structures that closely mimic natural extracellular matrix (ECM) is highly desirable. However, fabricating scaffolds with true nanofibers (< 100 nm) and submicrofibers (< 1 μm) remains a big challenge. In this work, to mimic the fibrillar structure of natural ECM, bacterial cellulose (BC) nanofibers were hybridized with cellulose acetate (CA) submicrofibers for the first time. The interpenetrated nano-submicron fibrous BC/CA scaffold was fabricated using the combined electrospinning and modified in situ biosynthesis method. The BC/CA scaffold has an integrated symmetrical nanostructure in which BC nanofibers (42 nm in diameter) penetrate into the submicrofibrous CA (820 nm in diameter) scaffold. The BC/CA scaffold shows an interconnected porous structure with a high porosity of > 90%. Additionally, the combination of CA submicrofibers with BC nanofibers leads to significantly improved mechanical properties over nanofibrous BC and submicrofibrous CA scaffolds and enlarged pores over nanofibrous BC scaffold. In addition, the biological behaviors of prepared BC/CA on MC3T3-E1 cells were investigated. Results suggested that BC/CA scaffold is beneficial for cell migration and proliferation. Moreover, the BC/CA scaffold shows higher alkaline phosphatase (ALP) activity, and calcium depositions. In addition, the hierarchical structures can effectively improve the expression of osteogenic gene (ALP mRNA and Runx2 mRNA) and protein (ALP). We believe that the methodology might provide biomimetic morphological microenvironments for enhanced tissue regeneration.
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