CRANIOFACIAL BONE DEFECT REPAIR USING POLYMER SCAFFOLDS AND CELL DERIVED MATRIX

Not scheduled
20m
ICE Krakow

ICE Krakow

ul. Marii Konopnickiej 17 30-302 Kraków

Speaker

Sasimonthon, Witchayut (Department of Materials Science and Engineering and Insigneo institute for in silico medicine, University of Sheffield )

Description

Introduction
Craniofacial bone defects can be caused from birth defect anomalies and road traffic accidents and affect vital functions such as chewing, swallowing, speaking, and breathing1. Autografts are the current gold standard for treating these defects but suffer from limited tissue available for harvest, long operation times, and donor site morbidity. Tissue-engineering has been known for its potential able to support craniofacial bone regeneration but materials that can surpass autografts advantages have not been identified. Poly(glycerolsebacate)(PGS) is an elastomer generally introduced for soft tissue regeneration which is biocompatible, biodegradable, and tailorable. Porogen leaching with sodium chloride salt is a simple cost-effective technique to fabricate 3D scaffolds. Cell derived extracellular matrix (ECM) after decellularisation has been shown to have a potential of enhancing osteoprogenitor cell attachment, proliferation, differentiation, and mineralisation2. However, decellularised matrix has limited mechanical properties and cannot be shaped to fill complex bone defects. Therefore, we aim to create 3D bone-like tissue for craniofacial repair using a combination of PGS and cell-derived ECM.

Methods
Porous PGS scaffolds were synthesised using a porogen leaching technique with a ratio of 1:3.5 of prepolymer to salt (w/w) and porosity and pore size assessed using pycnometry and scanning electron microscopy (SEM). Y201 (immortalised mesenchymal stem cell (MSC) cell line) attachment and matrix deposition onto the scaffolds were investigated by resazurin reduction assay and Western blot over 21 days. The scaffolds were then decellularised using 20mM ammonium hydroxide with 0.5% Triton X-100 for 24 hours on rocking machine. After being washed with cell culture medium for 72 hours on rocking machine, the scaffold then was soaked in 0.2 mg/ml DNase I solution for 24 hours to help reducing the immunological effect before being washed for another 24 hours. The decellularised and washed scaffolds were then seeded with fresh Y201 cells to elucidate if cell attachment and proliferation are enhanced by the decellularised matrix comparing to cell seeded on fresh scaffolds without any ECM (a control group).

Results
Pycnometer and SEM analysis showed that the ratios used produced a range of pore densities with pore size in the range of 50-400µm. The scaffolds supported cell attachment as assessed by resazurin and the deposition of key bone proteins including collagen, fibronectin, bone sialoprotein 2, and osteopontin as assessed by Western blot. After the decellurisaiotn process and re-seeding cell attachment was higher on scaffold containing ECM but the rate of cell growth was slower compared to the control group.

Conclusion
In summary, salt-leached PGS scaffolds support MSC growth and bone matrix deposition and have potential applications in craniofacial bone regeneration.

References

  1. Islam, S., Ahmed, M., Walton, G. M., Dinan, T. G. & Hoffman, G. R. J. Cranio-Maxillofacial Surg. 40, 82–85 (2012).
  2. Aldemir Dikici, B., Reilly, G. C. & Claeyssens, F. ACS Appl. Mater. Interfaces 12, 12510–12524 (2020).

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