Electrospinning Device: Tuning the microstructure and mechanical properties of freeze-dried silk scaffolds by prefreezing silk hydrogels and silk solutions

Background

The structure, morphology and mechanical properties of the scaffold can be adjusted by controlling the concentration of silk fibroin and the temperature of the pre-freezing treatment. Freeze-drying is a commonly used method for preparing porous silk fibroin scaffolds. It is fast and convenient, but phase separation during the freezing process may lead to the formation of sheet/wall structures, which is not conducive to the realization of nanofiber structures.

Micro-nanostructure of silk fibroin scaffolds

After pre-freezing silk fibroin solutions and hydrogels with different concentrations at different temperatures, the micro-nanostructure of the resulting scaffolds is different. Lower temperatures help to maintain the nanofiber structure of the hydrogel, while when quenched with liquid nitrogen, the nanofiber structure helps to generate macrochannels in the scaffold, which is beneficial for tissue engineering applications.

Mechanical properties of silk fibroin scaffolds

At the same silk fibroin concentration, the scaffolds prepared by pre-freezing silk fibroin solutions at different temperatures have different moduli. As the silk fibroin concentration increases, the compression modulus increases, while liquid nitrogen pre-freezing leads to the lowest modulus of the scaffold.

Secondary structure of silk fibroin scaffolds

FTIR analysis shows that amide III and random helical structures exist in silk fibroin scaffolds. The scaffolds prepared from silk fibroin solution have a high random coil content, and with the increase of silk fibroin concentration, they may have a higher β-fold content.

Application of electrospinning technology in the preparation of silk fibroin scaffolds

Electrospinning technology is widely used to produce porous nanofiber scaffolds with high specific surface area and microporous structure, which can simulate the nanoscale size and pore structure of extracellular matrix and support cell adhesion and growth. Electrospinning of silk fibroin and PLGA blends can prepare vascular tissue engineering scaffolds with good biocompatibility.

Innovative application of electrospinning equipment

Electrospinning technology can not only prepare traditional randomly oriented nanofibers, but also prepare oriented nanofiber scaffolds by changing the receiving device and applying electric and magnetic fields to assist in controlling the arrangement of deposited fibers. These oriented fiber scaffolds have important applications in the field of tissue regeneration.

Conclusion

The structure and performance of silk fibroin scaffolds can be optimized by controlling the concentration of silk fibroin and pre-freezing treatment conditions. Electrospinning technology, especially the preparation of oriented nanofibers, provides a new approach for the development of silk protein scaffolds, which helps to improve the cell compatibility and tissue regeneration ability of the scaffolds. These studies provide meaningful references for the research of oriented channel materials in bone tissue engineering scaffold materials and demonstrate the innovative application potential of electrospinning technology in tissue engineering.

Electrospinning Nanofibers Article Source:

https://doi.org/10.1016/j.jcis.2022.11.003