"3D Bioprinting: Methacrylate Collagen, Silk Fibroin and Montmorillonite Clay Bioink to Mimic the Bone Matrix"

• Grant number: 23/12039-0
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2024
• End date: January 31, 2026
• Field of knowledge: Engineering - Biomedical Engineering - Medical Engineering
• Principal Investigator: Eliana Aparecida de Rezende Duek
• Grantee: Eliana Aparecida de Rezende Duek
• Host Institution: Faculdade de Ciências Médicas e da Saúde (FCMS). Pontifícia Universidade Católica de São Paulo (PUC-SP). Sorocaba , SP, Brazil
• Associated researchers: Ariana de Souza Moraes ; Cedric Dicko ; Daniel Komatsu ; Moema de Alencar Hausen

Abstract

Currently, 3D bio-printing stands as a pivotal technique in the realm of fabricating skeletal frameworks, furnishing a noteworthy advancement to the field of bone tissue engineering. Aiming to confer upon these printed scaffolds properties that faithfully mimic natural structures, considerable endeavors have been dedicated to the quest for materials that not only exhibit osteogenic characteristics but also harmonize with tissue-specific rheological traits. Although collagen is renowned for its exceptional biocompatibility, its limited mechanical properties and predisposition to swift in vivo degradation pose challenges to its application. Within this context, the promising alternative of collagen methacrylate (ColMA) emerges, wherein rapid UV-light-catalyzed crosslinking yields a bio-ink endowed with remarkable mechanical strength. However, bio-inks based on ColMA, despite possessing the desired structural rigidity for 3D bio-printing, still exhibit mechanical vulnerabilities rendering them susceptible to rapid enzymatic degradation in the in vivo. To surmount this limitation, the incorporation of silk fibroin (FS) emerges as a promising approach. Apart from conferring osteoinductive capacity, FS has shown notable resistance to prolonged enzymatic degradation in the in vivo setting. However, even the combination of ColMA and FS has yet to satisfactorily emulate the mechanical properties of the original bone matrix. Furthermore, the reduced viscosity of the ColMA/FS-based bio-ink detrimentally affects the 3D bio-printing process. As a strategy to address these challenges, this project proposes the addition of a third element: an inorganic load comprising calcium-rich montmorillonite (MMT) clay, with intralamellar structure. This addition aims to create a mineral component akin to the bone matrix, fostering not only biological functions but also more effective cellular adhesion and proliferation mechanisms. The objective is to enhance the osteointegration process. Consequently, the formulation of ColMA/FS-based bio-ink associated with MMT clay will not only bolster the mechanical robustness of the 3D-printed scaffold (ColMA/FS/MMT) but also decelerate in vivo degradation rates and modulate the rheological properties of the bio-ink. The ultimate goal is to attain a structure that prominently emulates the attributes of a bone matrix. To achieve this, the ColMA/FS/MMT-based bio-ink will undergo rheological analyses to optimize its composition for 3D bio-printing. The resultant scaffolds will be characterized through FTIR spectroscopy, as well as thermal analyses using TGA and DSC. Additionally, degradation assays will be conducted. To assess its osteointegrative potential, biocompatibility and osteodifferentiation analyses, employing confocal microscopy and other marker identification assays, will be employed to establish and outline its potential for mimicking an immature, osteogenic bone matrix. The underlying perspective of this study is to significantly contribute to the development of a novel bio-ink formulation with the potential for future clinical use as an osteoinductive substitute. (AU)