The effects of pore size in bilayered poly(lactide-co-glycolide) scaffolds on restoring osteochondral defects in rabbits

Abstract

Bilayered porous scaffolds have recently attracted interest because of their considerable promise for repairing osteochondral defects. However, determination of optimal pore size in bilayered porous scaffolds remains an important issue. This study investigated the in vivo effects of pore size in bilayered scaffolds using a rabbit model of osteochondral defects. We fabricated five types of integrated bilayered poly(lactide-co-glycolide) (PLGA) scaffolds with different pore sizes in the chondral and osseous layers (50-100 µm, 100-200 µm, 200-300 µm, and 300-450 µm). A subset of bilayered scaffolds seeded with or without allogenic bone marrow mesenchymal stem cells (BMSCs) was implanted in rabbit osteochondral defects. All of the cell/scaffold composite constructs supported the simultaneous regeneration of articular cartilage and subchondral bone, but the best results were observed in cell-seeded PLGA scaffolds with 100-200 µm pores in the chondral layer and 300-450 µm pores in the osseous layer. Our study supports the concept that the effects of pore size on osteochondral repair should be taken into consideration during scaffold design for tissue engineering.

Coupling Freshly Isolated CD44+ Infrapatellar Fat Pad‐Derived Stromal Cells with a TGF‐β3 Eluting Cartilage ECM‐Derived Scaffold as a Single‐Stage Strategy for Promoting Chondrogenesis

“…[27] Within osteochondral defects, it has been demonstrated that cell-seeded poly(lactide-co-glycolide) (PLGA) scaffolds with 100-200 μm pores in the chondral layer and 300-450 μm pores in the osseous layer best supported joint regeneration. [28] In addition to pore size, scaffold stiffness has also been shown to regulate stem cell differentiation, with softer scaffolds shown to support chondrogenesis, and stiffer scaffolds shown to support osteogenesis. [17] Therefore the enhanced chondrogenesis observed in the higher porosity/lower concentration ECM-derived scaffolds observed in this study may be due, at least in part, to alterations in scaffold stiffness as the concentration of the scaffold is reduced.…”

A biphasic scaffold based on silk and bioactive ceramic with stratified properties for osteochondral tissue regeneration

“…The two phases were well-integrated at a continuous interface to form the coherent structure of the biphasic scaffold, via a simple fabrication method that allowed control over the size of the interface region. The realisation of this biphasic scaffold design therefore circumvented many of the common issues encountered with other integrated scaffold designs featuring stratified layers with heterogeneous properties, including the lack of smooth transition between phases, 38,39,41,42,45,47,49 lack of control over the size of the interface region, 44,48 and complicated or tedious fabrication methods. 42,43 …”

Osteochondral Tissue Engineering with Biphasic Scaffold: Current Strategies and Techniques

“…Summarizing recent animal studies (Table 1), the work has been focused on not only investigating the effectiveness of materials or cells, but also on applying several new concepts and techniques such as mechanical, 105 microstructural, 75 and local microenvironment modification 86 for the design and fabrication of scaffolds. In addition, the most suitable biomaterials for the cartilage or subchondral bone layers have not been fully investigated, while there are many biomaterials available for osteochondral repair.…”

“…74 Synthetic polymers are also attractive, because they can be fabricated into various shapes with a desired pore according to the speed of cell migration or tissue in-growth. 75 Moreover, the progression of current techniques such as electrospinning methods and the 3D printer have enabled the simple design and fabrication of scaffolds. [76][77][78] On the other hand, synthetic polymers have limitations in bioactivity due to their hydrophobic surface not supporting cell attachment and proliferation.…”