Speaker
Description
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3D-printed personalised scaffolds are an attractive approach for mandibular bone repair. Poor mechanical stability of medical grade ceramics is a disadvantage. Also, delivery and retention of regenerative cells within 3D-printed scaffolds remains a challenge. This work aims to create 3D-printed personalised scaffolds based on a novel combination of materials with enhanced mechanical and cell-adhesion properties and with a configurable layered composition including cell-laden collagen membranes for improved cell delivery. The printable ink is created in ethylene carbonate (EC) and consists of 40% (w/V) PLGA to support printability and mechanical strength, 20% (w/V) β-TCP to increase osteoconductivity and 10% (w/V) TPU for elasticity. Solvent-based printing is applied using the RegenHu 3D Discovery® Bioprinter. A 3D model of a mandibular defect is derived from CT scans, then sliced and modified with CAD to obtain LEGO®-like structures. The personalised scaffolds are printed as a series of layers incorporating an interlocking mechanism. Human bone marrow derived mesenchymal stromal cells (MSCs, obtained will full ethical approval) are seeded and kept for 21 days under osteogenic culture conditions on two commercially available collagen membranes: 1. Lyostypt (B. Braun) and 2. Collagen Cell Carrier (CCC) (Viscofan Bio Engineering) (N=3). Viability of MSCs on the collagen membranes placed in between 3D-printed scaffold layers is examined via live-dead staining after 8 days of culture (N=1). Water-mediated EC removal leads to surface microporosity and roughness, both confirmed by SEM, and both favourable properties for improved cell adhesion. Mechanical compression test (N=10) of the 3D-printed scaffold shows improved stiffness and ductility compared to the commercially available ceramic Osteoink®. Under osteogenic culture conditions, MSCs seeded on collagen membranes have increased alkaline phosphate activity at day 14 compared to controls, with an effect more profound for the CCC. When MSC are seeded on the collagen membranes, expression of bone sialoprotein mRNA is upregulated not only in the osteogenic medium but also in the control medium. Live-dead staining shows good cell survival on the Lyostypt cultured in between 3D-printed scaffold layers, while a higher number of dead cells are detected on the CCC. 3D-printed scaffold biocompatibility and cell proliferation is shown by live-dead staining over 8 days of cell culture. Large scale personalised mandibular implants can be successfully printed, assembled and combined with cell-laden collagen membranes. We propose a novel 3D printable ink for mandibular bone reconstruction as an alternative to ceramics. Ongoing tests aim to demonstrate that osteogenic capabilities of the 3D-printed scaffold and efficient seeding of biologics intraoperatively to promote osteogenesis and vascularisation."
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