Electrospinning Equipment: The molecular conformation of silk fibroin regulates osteoblast behavior by modulating the stability of adsorbed protein-material interfaces

Research background and motivation

Silk fibroin fiber (SF) is widely used to construct rigid material interfaces that support bone formation due to its excellent biocompatibility and biodegradability. Converting SF molecules from random coil parts to β-sheets is a key step in the preparation of SF-based materials, because the β-sheet structure makes the material insoluble in water, thereby enhancing its stability. However, the effect of SF conformation on osteoblast behavior is still unclear, especially how the β-sheet content affects osteoblast behavior at the material interface.

Research methods and procedures

Preparation of SF matrices with different β-sheet contents: Three rigid SF matrices were prepared by varying the β-sheet content (high, medium, and low). These matrices were comparable in chemical composition, surface morphology, and wettability.

Evaluation of material interface stability: Using adsorbed fibronectin (FN) as a model cell adhesion protein, the stability of the adsorbed protein-material interface, including the surface stability of the SF matrix and the detachment resistance of FN, was studied.

Cell behavior observation: The diffusion behavior, cytoskeleton organization, nuclear translocation, and activation of YAP/TAZ and RUNX2 of bone marrow mesenchymal stem cells (BMSCs) on SF matrices with different β-sheet contents were observed.

Key conclusions and results

Interface stability is associated with β-sheet content: As the β-sheet content of the SF matrix increases, the stability of the adsorbed FN on the material interface increases, which is manifested as stronger surface stability and higher FN detachment resistance.

Cell behavior is affected by interface stability: On SF matrices with high β-sheet content, BMSCs exhibit greater cytoskeleton-related focal adhesions, higher-order cytoskeleton organization, and longer cell spreading, as well as enhanced nuclear translocation and activation of YAP/TAZ and RUNX2.

Osteogenic differentiation is regulated by β-sheet content: SF matrices with high β-sheet content promote osteogenic differentiation of BMSCs, indicating that β-sheet content affects the behavior of osteoblasts by regulating the stability of the adsorbed protein-material interface.

Research significance and future directions

This study highlights the important role of adsorbed protein-material interface stability in cellular mechanotransduction and sensing of rigid SF matrices with different β-sheet contents. This finding has important implications for the design of rigid biomaterials, suggesting that the effect of material interface stability on cell behavior should be considered when engineering biomaterials. Future studies are needed to further explore how the stability of this protein-material interface regulates the behavior of BMSCs on rigid material surfaces under three-dimensional, long-term, and multifactorial in vivo conditions.

Electrospinning Nanofibers Article Source:

https://doi.org/10.1038/s41413-020-00130-0