Chen, Hongyi; (2023) 3D printing hybrid scaffold with hydrogel and filler-loaded PCL for osteochondral tissue engineering. Doctoral thesis (Ph.D), UCL (University College London).

Text Chen_10166927_Thesis.pdf Access restricted to UCL open access staff until 1 April 2026. Download (7MB)

Abstract

Osteoarthritis has been a leading cause of disability in older adults. Tissue engineered scaffolds have shown to facilitate tissue regeneration after implantation to the defect site. 3D printing techniques can fabricate complex scaffolds specific to patients and clinical conditions and especially, direct ink writing allows the use of temperature-sensitive materials and the incorporation of cells. This study aims to develop hybrid materials for 3D printing osteochondral scaffolds. Hydrogel recapitulates several features of natural extra cellular matrix and is hence used for cartilage regeneration. Pluronic F127 hydrogel has been used due to its unique thermogelling property. Laponite, a synthetic nanoclay, is used as the viscosity enhancer to provide structural support for F127. Polycaprolactone (PCL), an FDA-approved polyester, is used for subchondral bone scaffolds as it has high biocompatibility, stable degradation rate and high toughness. To further improve the bioactivity of PCL, fillers including Laponite and hydroxyapatite (HA) microparticles and nanoparticles were loaded up to 30 wt%. The addition of fillers in both hydrogel and PCL inks has significantly enhanced viscosity, yield stress and shear-thinning behavior. These result in higher printability due to higher resistance to post-printing deformation and can support porous scaffold structures with more than 30 layers. The mechanical properties of 3D printed PCL-based dumbbell specimens were measured. The addition of fillers in PCL has improved Young’s modulus significantly indicating a strong polymer-nanoparticle connection. As for printing orientations, 90° orientation has significantly higher mechanical properties than 0° orientation due to better filament bonding. Cells attached on porous scaffolds 3D printed by both hydrogels and filler-loaded PCL with high viability (>90%). The addition of fillers has enhanced proliferation and mineralization throughout the scaffold significantly. The filament patterns on 0° orientation have guided cell attachment and alignment. In conclusion, hydrogels and PCL-based inks with high printability, mechanical properties biocompatibility, and bioactivity were developed for 3D printing osteochondral scaffolds.

Download activity - last month

Export as CSVJSONXML

Download activity - last 12 months

Export as CSVJSONXML

Downloads by country - last 12 months

Export as XMLJSONCSV

Archive Staff Only

View Item