Kartogenin-loaded silk fibroin–chondroitin sulfate hybrid hydrogel with tailored β-sheet content: control release studies and biological activity

Abstract

Silk fibroin (SF)–chondroitin sulfate (CS)-hybrid hydrogels (HHGs) containing kartogenin (KGN) were synthesized by the induction of di-tyrosine bonds, using enzymatic crosslinking in SF/CS blend solution. Then, physical crosslinking was performed to optimize the HHG properties. The results showed that the increasing of the β-sheet content as side effect of physical crosslinking from 10% to 40% affects KGN accumulative release percentage almost three times. Biological investigations using C28/I2 human chondrocyte cell line showed that the presence of KGN, CS, and optimized β-sheets content improved cell supporting behavior of HHG. Finally, KGN loaded HHG might be a promising candidate for cartilage repair.

Graphical Abstract

Schematic representation of fabrication of the dual crosslinked hybrid hydrogel containing silk fibroin and chondroitin sulfate by enzymatic crosslinking and physical crosslinking method for kartogenin release. Enzymatic crosslinking: shaping di-tyrosine formation bond between silk fibroin phenol groups and locking physically chondroitin sulfate between silk fibroin β-sheets. Physical crosslinking with water and/or ethanol treatments end up in increased β-sheets content.

Keywords:

• β-sheet
• kartogenin
• physical crosslinking
• release kinetics
• silk fibroin

Acknowledgements

The authors would like to thank Dr. Saeed Bahrami and Dr. Davood Sadeghi for their assistance in analyzing the biological results. The authors would like to express their gratitude to the office of Professional Laboratories and Technology Services in Amirkabir University of Technology (Tehran Polytechnic) for supporting this research under Grant Number 1401-0506.

Author contributions

Maryam Farokhi: conceptualization, methodology, validation, formal analysis, investigation, writing – original draft, writing – review and editing, and visualization. Atefeh Solouk: conceptualization, methodology, resources, writing – review and editing, supervision, funding acquisition, and project administration. Hamid Mirzadeh: conceptualization, methodology, resources, supervision, project administration, and funding acquisition. Andreas Teuschl-Woller: conceptualization, supervision, methodology, resources, and writing-review and editing. Heinz Redl: conceptualization, methodology, resources, supervision, and project administration.

Ethical approval

Since this is an in vitro study, no ethical declaration is required for this study.

Disclosure statement

There is no conflict of interest associated with this research.

Data availability statement

Not applicable.

Additional information

Funding

The authors would like to express their gratitude to the Office of Professional Laboratories and Technology Services in Amirkabir University of Technology (Tehran Polytechnic) for supporting this research under Grant Number 1401-0506.