Poster BB10 - 3D Bioprinted Osteochondral Composite Tissue Constructs for Reconstruction

Friday, October 25, 2024

3:30 PM - 4:30 PM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Siyuan Li (she/her/hers)

Ph.D. student
Wake Forest Institute for Regenerative Medicine (WFIRM)
Winston-Salem, North Carolina, United States

Co-Author(s)

DG

Denethia Green

Research Technician
Wake Forest Institute for Regenerative Medicine, United States

Last Author(s)

SL

Sang Jin Lee

Professor
Wake Forest University School of Medicine, United States

Introduction: Osteochondral defects (OCD) lead to damage in both cartilage and the underlying bone. The limited regenerative capacity of these tissues can perpetually extend to the affected region. Current treatment approaches, such as autograft, allograft, and artificial transplants, face challenges such as donor availability, disease transmission, immune response, inadequate osteoinductive properties. Microfracture surgery, an alternative, yields optimal results in young patients with robust regenerative ability and limited defect areas. Therefore, these treatments’ limitations have prompted exploration into tissue-engineered bone and cartilage constructs for OCD. In this study, we hypothesized that enhancing the regional differences with the interface between bone and cartilage could overcome the current therapeutic limitations. This study aimed to overcome the limitations of existing treatment options by using 3D bioprinting strategies to develop osteochondral composite tissues with a functional interface, thus achieving coordinated tissue functions.

Materials and

Methods: A two-layered osteochondral unit containing human placental stem cells (hPSC) was fabricated using a digital light processing (DLP) bioprinter (CGBio, South Korea). A gelatin methacryloyl (GelMA)-based bioink formulation was used, incorporating bone morphogenetic protein 2 (BMP-2) in the osteogenic layer and transforming growth factor beta-3 (TGF-β3) in the chondrogenic layer. This formulation facilitates differentiation into bone, cartilage, and subchondral transition tissues in the corresponding layers. The printed composite constructs were characterized by measuring the compressive mechanical properties and biological evaluations. After 7, 14, and 21 days in the co-differentiation medium, the composite tissue constructs were tested with Alizarin Red S staining for bone, Safranin O Red staining for cartilage, and H&E staining for morphology.

Results, Conclusions, and Discussions: We successfully fabricated multi-layered osteochondral composite tissue constructs using the 3D bioprinting process. Each printed layer maintained osteogenic and chondrogenic microenvironments, respectively, to develop osteochondral tissue with interfacial tissue. Further analyses to determine composite tissue formation are being performed through histological and immunohistochemical evaluations, as well as extracellular matrix (ECM) protein assays.
We utilized the GelMA-based hydrogel bioink systems for hPSC osteogenesis and chondrogenesis within the same basic culture medium. This multi-layer structure provided tissue-specific mechanical properties for each tissue, with tissue-specific growth factors embedded in the corresponding layers. Simultaneous osteogenesis and chondrogenesis ensure a smooth transition between the differentiated bone and cartilage.
This printed osteochondral composite tissue construct provided tissue-specific biomimetic environments for osteogenic and chondrogenic differentiation using two different bioink formulations. The success of this study demonstrates the potential for printing multiple tissues within a single structure. Additionally, the smooth transition from simultaneous differentiation, achieved through this system, mimicked native intercellular communication.

Acknowledgements (Optional):