@article {19680, title = {Hierarchical bilayered silk fibroin scaffolds containing ZnSr-β-TCP particles for osteochondral tissue regeneration}, journal = {CHEM2NATURE Final Conference}, year = {2018}, month = {2018-10-25 00:00:00}, address = {Porto, Portugal}, abstract = {

Osteochondral (OC) tissue engineering strategy created bilayered scaffolds consisting of a top articular cartilage-like layer and an underlying subchondral bone-like layer that can better mimic the structural, mechanical and biological properties of the native OC tissue1. Among\ natural biopolymers, silk fibroin (SF) exhibits tunable mechanical properties, chemical versatility and biocompatibility2. On the other side, the incorporation of ionic dopants (ZnSr) into bioresorbable inorganic\ β-tricalcium phosphate(β-TCP) have shown to improve the osteoconductivity and neovascularization of\ SF scaffolds3. In this study, we aim to produce novel bilayered scaffolds with improved viscoelastic properties, by combining\ enzymatically crosslinked\ SF hydrogels (HRP-SF) and\ β-TCP powders doped with Zn and Sr. Pure\ β-TCP was used for preparing bilayered scaffolds used as control.\ Physicochemical characterization\ was assessed through XRD, SEM and micro-CT. Structural integrity was evaluated by degradation profile analysisand themechanical properties determined in static and dynamic conditions.\ Bioactivity evaluation was performed by immersing the scaffolds in SBF solution\ up to 30 days. The\ in vitrocell\ adhesion, proliferation and activity were characterized by co-culturing human articular chondrocytes (hACs) and human osteoblasts (hOBs) in the respective layers of the bilayered scaffolds up to 14 days. Monocultured individual scaffolds were used as controls. The OC tissue regeneration by the bilayered scaffolds was tested after 8 weeks of implantation in rabbit critical size OC defects.\ The results showed interconnected porosity and homogeneous\ β-TCP distribution into the subchondral bone-like layers.\ The bilayered scaffolds presented superior mechanical properties with special relevance for the ZnSr-doped bilayered scaffolds. Co-cultured cells adhered and proliferated on the bilayered scaffolds, showing\ collagen formation and GAGs deposition.\ The bilayered scaffolds were firmly integrated into the host rabbit OC tissue, HRP-SF layers allowed cartilage tissue regeneration and infiltration within the porous structures, whereas the underlying composite layers showed bone tissue ingrowth and blood vessels infiltration. In brief,\ the structural adaptability and suitable mechanical properties of the proposed bilayered scaffolds, combined with the biological performance achieved using a co-culturing system and\ in vivoOC implantation, make these scaffolds a promising strategy for OC defects regeneration.

References

[1] L.-P. Yan et al., Acta biomaterialia,12:227-241, 2015

[2] P.\ Bhattacharjee et al., Acta Biomaterialia, 63:1-17, 2017

[3] S. Pina et al., Cells Tissues Organs, 204:150, 2017

Acknowledgments:

Portuguese Foundation for Science and Technology (FCT) project\ M-ERA-NET/0001/2014 project.\ Investigator FCT programs IF/00423/2012, IF/00411/2013\ and IF/01285/2015. Financial support from FCT/MCTES (Funda{\c c}{\~a}o para a Ci{\^e}ncia e a Tecnologia/ Minist{\'e}rio da Ci{\^e}ncia, Tecnologia, e Ensino Superior) and Fundo Social Europeu atrav{\'e}s do Programa Operacional do Capital Humano (FSE/POCH), PD/59/2013, PD/BD/113806/2015.

}, keywords = {Bilayered Scaffold, HRP-mediated silk fibroin hydrogel, Ionicdopants, Osteochondral tissue engineering., β-tricalcium phosphate}, author = {Ribeiro, V. P. and Cengiz, I. F. and Canadas, R. F. and Costa, J. B. and Vieira, S. and da Silva Morais, A. and Vilela, C. and Garc{\'\i}a-Fern{\'a}ndez, L. and Fern{\'a}ndez-Gutierrez, M. and San-Rom{\'a}n, J. and Oliveira, J. M. and Reis, R. L.} }