Polydopamine Coating-Mediated Immobilization of BMP-2 on Polyethylene Terephthalate-Based Artificial Ligaments for Enhanced Bioactivity

Abstract

Background/objectives: Polyethylene terephthalate (PET)-based artificial ligaments are one of the most commonly used grafts in anterior cruciate ligament (ACL) reconstruction surgery. However, the lack of favorable hydrophilicity and cell attachment for PET highly impeded its widespread application in clinical practice. Studies found that surface modification on PET materials could enhance the biocompatibility and bioactivity of PET ligaments. In this study, we immobilized bone morphogenetic protein-2 (BMP-2) on the surface of PET ligaments mediated by polydopamine (PDA) coating and investigated the bioactivation and graft-to-bone healing effect of the modified grafts in vivo and in vitro.Methods: In this study, we prepared the PDA coating and subsequent BMP-2-immobilized PET artificial ligaments. Scanning electron microscopy (SEM) was used to analyze the morphological changes of the modified grafts. In addition, the surface wettability properties of the modified ligaments, amount of immobilized BMP 2, and the release of BMP-2 during a dynamic period up to 28 days were tested. Then, the attachment and proliferation of rat bone mesenchymal stem cells (rBMSCs) on grafts were examined by SEM and Cell Counting Kit-8 (CCK-8) assay, respectively. Alkaline phosphatase (ALP) assay, RT-PCR, and Alizarin Red S staining were performed to test the osteoinduction property. For in vivo experiments, an extra-articular graft-to-bone healing model in rabbits was established. At 8 weeks after surgery, biomechanical tests, micro-CT, and histological staining were performed on harvested samples.Results: A surface morphological analysis verified the success of the PDA coating. The wettability of the PET artificial ligaments was improved, and more than 80% of BMP-2 stably remained on the graft surface for 28 days. The modified grafts could significantly enhance the proliferation, attachment, as well as expression of ALP and osteogenic-related genes, which demonstrated the favorable bioactivity of the grafts immobilized with BMP-2 in vitro. Moreover, the grafts immobilized with BMP-2 at a concentration of 138.4 ± 10.6 ng/cm2 could highly improve the biomechanical properties, bone regeneration, and healing between grafts and host bone after the implantation into the rabbits compared with the PDA-PET group or the PET group.Conclusion: The immobilization of BMP-2 mediated by polydopamine coating on PET artificial ligament surface could enhance the compatibility and bioactivity of the scaffolds and the graft-to-bone healing in vivo.

High‐Performance Artificial Ligament Made from Helical Polyester Fibers Wrapped with Aligned Carbon Nanotube Sheets

“…[ 13 ] PET fibers, which are state‐of‐the‐art synthetic ligaments, are widely used clinically. [ 8a,14 ] After twisting multiple primary composite fibers together, secondary helical fibers (Figure 1e) were obtained, equivalent to the collagen bundles in the native ligament. HCF grafts were successfully fabricated by further twisting and folding the secondary helical fibers (Figure 1b,f).…”

Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

“…The study by Kang et al revealed that applying a polydopamine (PDA) coating to immobilize bone morphogenetic protein-2 (BMP-2) on PET artificial ligaments significantly boosts their biocompatibility and bioactivity, ultimately enhancing graft-to-bone healing (Figure 4B). [122] This innovative surface modification approach may lead to improved outcomes in ACLR surgeries utilizing PET-based artificial ligaments. Vaquette investigated the impact of polystyrene sodium sulfonate (PolyNaSS) grafting on the osseointegration of LARS used for ACLR.…”

Nerve Decellularized Matrix Composite Scaffold With High Antibacterial Activity for Nerve Regeneration

“…As time went by, the droplets gradually infiltrate the scaffolds and the contact angle became smaller. The suitable hydrophilicity of the scaffolds could facilitate cell adhesion, extension, nutrient penetration and factor diffusion, so as to better support the growth of cells (Kang et al, 2021).…”