Abstract
Osteochondral defects remain one of the most difficult clinical challenges in regenerative medicine, which lie as a complex structural and biochemical gradient between articular cartilage and subchondral bone. Calcium phosphate (CaP) based materials were engineered, through Continuous Polymeric Flow Synthesis (CPFS) methodology [1], for the production of highly porous homogeneous, and bioactive constructs with controlled physicochemical parameters. These CPFS derived biomaterials were then processed into a bi-layered scaffold through electrospinning, mimicking the native osteochondral junction, a chondral layer for cartilage regeneration and an underlying subchondral layer to promote bone regeneration. CaP powders were synthesized via CPFS from aqueous Ca2+, Sr2+, Ba2+ solutions, and doped with trace ions Fe2+/Fe3+, Mg2+, Zn2+, Sr2+ for alteration of degradation and bioactivity [2,3]. The powders ≈ 264 m2g-1 surface area were characterized by X-ray diffraction FTIR, XPS, TEM, SEM, DLS and BET analysis. Bilayered hybrid scaffolds were manufactured via electrospinning, having nanofibrous chondral and CaP/polymer subchondral layers. Compression testing was performed to evaluate the mechanical behaviour. Human Mesenchymal stem cells hMSCs were seeded on scaffolds for the examination of cell adhesion, proliferation, osteo and chondrogenic differentiation. In vivo performance was analyzed in 4 mm × 4 mm depth rabbit femoral condyle defects 8-12 weeks, followed by histological H&E, Safranin O and microCT analysis [4]. Doped CaP powders showed phase composition control and high porosity. Electrospun constructs possessed compression strengths comparable to cancellous bone and promoted hMSC attachment and differentiation. Fe/Sr co-doping accelerated CaP degradation and enhanced MSC adhesion. Bi-layers promoted hyaline-like cartilage in the chondral layer and well-mineralized bone in the subchondral region with seamless union and lack of inflammation in rabbits. In conclusion,
CPFS permits the scalable synthesis of doped CaP that can be scaled into bilayers conforming to the osteochondral interface.
Further informations: https://www.elaine.uni-rostock.de/kolloquium/
The lecture is hosted by project B01 (Seitz, Riaz)