A Novel One-Pot Synthesis and Characterization of Silk Fibroin/α-Calcium Sulfate Hemihydrate for Bone Regeneration

Aditi Pandey; Tzu-Sen Yang; Shu-Lien Cheng; Ching-Shuan Huang; Agnese Brangule; Aivaras Kareiva; Jen-Chang Yang

doi:10.3390/polym13121996

A Novel One-Pot Synthesis and Characterization of Silk Fibroin/α-Calcium Sulfate Hemihydrate for Bone Regeneration

Polymers (Basel). 2021 Jun 18;13(12):1996. doi: 10.3390/polym13121996.

Authors

Aditi Pandey¹, Tzu-Sen Yang², Shu-Lien Cheng¹, Ching-Shuan Huang³, Agnese Brangule⁴, Aivaras Kareiva⁵, Jen-Chang Yang^{1

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Affiliations

¹ Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11052, Taiwan.
² Graduate Institute of Biomedical Optomechatronics, Taipei Medical University, Taipei 11031, Taiwan.
³ School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 11031, Taiwan.
⁴ Department of Pharmaceutical Chemistry, Riga Stradins University, LV-1007 Rīga, Latvia.
⁵ Institute of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania.
⁶ International Ph.D. Program in Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan.
⁷ Research Center of Biomedical Device, Taipei Medical University, Taipei 11052, Taiwan.
⁸ Research Center of Digital Oral Science and Technology, Taipei Medical University, Taipei 11052, Taiwan.

Abstract

This study aims to fabricate silk fibroin/calcium sulfate (SF/CS) composites by one-pot synthesis for bone regeneration applications. The SF was harvested from degummed silkworm cocoons, dissolved in a solvent system comprising of calcium chloride:ethanol:water (1:2:8), and then mixed with a stoichiometric amount of sodium sulfate to prepare various SF/CS composites. The crystal pattern, glass transition temperature, and chemical composition of SF/CS samples were analyzed by XRD, DSC, and FTIR, respectively. These characterizations revealed the successful synthesis of pure calcium sulfate dihydrate (CSD) and calcium sulfate hemihydrate (CSH) when it was combined with SF. The thermal analysis through DSC indicated molecular-level interaction between the SF and CS. The FTIR deconvolution spectra demonstrated an increment in the β-sheet content by increasing CS content in the composites. The investigation into the morphology of the composites using SEM revealed the formation of plate-like dihydrate in the pure CS sample, while rod-like structures of α-CSH surrounded by SF in the composites were observed. The compressive strength of the hydrated 10 and 20% SF-incorporated CSH composites portrayed more than a twofold enhancement (statistically significant) in comparison to that of the pure CS samples. Reduced compressive strength was observed upon further increasing the SF content, possibly due to SF agglomeration that restricted its uniform distribution. Therefore, the one-pot synthesized SF/CS composites demonstrated suitable chemical, thermal, and morphological properties. However, additional biological analysis of its potential use as bone substitutes is required.

Keywords: calcium sulfate hemihydrate; silk fibroin.