Silk Fibroin and Argentine Clays for Bone Reconstruction: a Nobel Hybrid Material for Bones

VALERIA E. BOSIO; EMILIANO BERTOLI

Rodas

Congreso; TERMIS EU 2019; 2019

TERMIS (Tissue Engineering and Regenerative Medicine International Society)

INTRODUCTION: Reconstructed Silk Fibroin (SF) from Bombyx mori is a biopolymer with biodegradability and biocompatibility for long-term medical implants. The versatility of this material for different structures and the possibility to be degraded with the time shows an advantage to rebuild damaged bones by Tisse Engineering (TE). However, a biomimicry of natural 3D bone structure made with silk needs to be mechanically reinforced. Herein, we ventured to developing a hybrid material with Montmorilonite (MMT), a natural clay from argentine environments, and SF, assessing the influence of these clays in the already known silk porous structures.METHODS: Silk porous sponges were prepared by salt-leaching method following previously reported protocol [1] with some modifications. NaCl salt was sieved with metal mesh to obtain particle size distributions between 500 and 590 µm and added into SF aqueous solution (with or without Polyvinyl Alcohol (PVA), Alendronate (Alen) or MMT at a 2:1 (w/v) ratio), in tube-shaped containers. Deposition and inclusion methods were used to add MMT to the SF scaffolds. After that, scaffolds were drying at room temperature for 2 hs without stirring before their stored. Characterization of the new materials was carried out by SEM, FTIR, TGA, DSC, Compression resistance analysis & Encapsulation of deformable liposomes loaded with fluorescein.RESULTS: All the SF-based scaffolds containing PVA, Alen or MMT presented significant increase (p < 0.001) of compression resistance with better results when MMT was present. FT-IR, TGA/DSC analysis suggest interactions between PVA and MMT with the SF correlated with a significant increase in the thermal stability of the hybrid materials compared with SF scaffolds. To evaluate the capacity of the hybrid scaffolds of loading/release cargo molecules during bone tissue regeneration process, deformable liposomes with fluorescein as model drug were included and studied in the systems, showing the capability of these materials to load and release drugs without loosing the structure and mechanical propertiesDISCUSSION & CONCLUSIONS: The results illustrate the beneficial effect of argentine natural MMT to enhance the properties of SF porous materials to be used as bone scaffolds for TE.