R. Begum (Bristol, GB)
University of Bristol Cellular and Molecular MedicinePresenter Of 1 Presentation
16.2.8 - The Development of an Anisotropic Composite Silk Nanofibre Bioink for Cartilage Tissue Engineering
Abstract
Purpose
To date, the majority of bioinks comprise highly isotropic structures with poor mechanical properties, which in turn gives rise to engineered tissue with simple unnatural extracellular matrices. This is particularly pertinent to the fabrication of cartilage tissue, which has a highly organised ultrastructure, supporting its anisotropic response to mechanical loading. Accordingly, we present on the development of an anisotropic composite bioink, comprising silk nanofibers aligned in a microporous alginate hydrogel.
Methods and Materials
Silk fibroin was electrospun and processed to generate monodispersed nanofibres with high aspect ratios. The nanofibres were combined with a sodium alginate and Pluronic F127 bioink (Armstrong et al., Adv.Health.Mat, 2016) and the mechanical and rheological properties elucidated using uniaxial compression and rotational rheometry, respectively. The composite bioink was then used to bioprint human mesenchymal stem cells (hMSCs) and the impact of this mechanical reinforcement on the chondrogenic differentiation of the stem cells was investigated.
Results
Reinforcement of the bioink using silk nanofibres increased its compressive modulus (Figure 1), and rheological analysis confirmed its shear-thinning properties. Furthermore, the extrusion printing process drove shear alignment of the nanofibres and the resulting bioink supported the viability of hMSCs (Figure 2). Moreover, analysis of the extracellular matrix produced by the hMSCs in the reinforced bioink confirmed its chondroinductive potential.
Conclusion
Incorporating high aspect ratio silk nanofibres in to an alginate-based bioink improved its mechanical properties. Bioprinting with hMSCs resulted in shear-alignment of the nanofibres and improved the chondrogenic potential of the stem cells. Functionalising these nanofibres with inherent cues could serve as a mechanism to tailor the behaviour of stem cells and fabricate biomimetic zonal cartilage tissue.