Profiled polyethylene terephthalate filaments that incorporate collagen and calcium phosphate enhance ligamentisation and bone formation

Abstract

Polyethylene terephthalate (PET) artificial ligaments offer an unlimited source of ligaments without donor-site-related morbidity and with good mechanical properties for a rapid return to sporting activities. Developing PET artificial ligaments with excellent ligamentisation and ligament-bone healing is still a considerable challenge. This study aimed to investigate the effects of the profiled PET/collagen/calcium phosphate (PET/C/CaP) ligament upon cell growth, ligamentisation and ligament-bone healing in vitro and in vivo. Profiled PET/C/CaP filaments were made by melt-spinning process with 2 % CaP hybrid spinning and collagen coating. Rat mesenchymal stem cells (MSCs) were cultured on the profiled PET/C filaments for cytotoxicity, viability, scanning electron microscopy (SEM) and ligament-related gene expression analysis. MSCs’ osteogenic capacity on the profiled PET/CaP filaments was identified by detecting osteogenic gene expression and alizarin red S staining. For in vivo verification, an animal study was performed to evaluate the effect of the profiled PET/C/CaP ligament in a rabbit knee medial collateral ligament reinforcement reconstruction model. The graft ligamentisation and bone formation were investigated by SEM, histology, microcomputed tomography and mechanical tests. The profiled PET/C filaments enhanced MSC proliferation and ligament-related gene expression. Furthermore, they enhanced osteogenic gene expression, alkaline phosphatase activity and mineralisation of MSCs. The in vivo study indicated that the profiled PET/C/CaP ligament enhanced ligamentous matrix remodelling and bone formation. Therefore, their use is an effective strategy for promoting MSCs’ ligamentous and osteogenic potential in vitro and enhancing ligamentous matrix remodelling and bone formation in vivo.

Engineering an extracellular matrix-functionalized, load-bearing tendon substitute for effective repair of large-to-massive tendon defects

“…For instance, combining ECM with synthetic biomaterials may be expected to yield a synergetic effect between natural and synthetic polymers [ 18 ]. Recent efforts have included embedding collagen-glycosaminoglycan scaffolds with 3D-printed synthetic acrylonitrile butadiene styrene polymers [ 25 ], electrochemical alignment of collagen to produce mechanically-strong ECM-based scaffolds [ 26 ], and collagen gel incorporating to a nondegradable PET filaments [ 27 ], These approaches have attained ultimate stresses (0.9 MPa) [ 25 ] and ultimate loads (59.9 N) [ 26 ], that approach those of native tendons (human supraspinatus tendon (SSPT), the most frequently torn rotator cuff tendon; ultimate stresses: 11.9–22.1 MPa [ 28 ]; ultimate load: 652 N) [ 29 ]. However, there are few reports of animal studies utilizing large-to-massive tendon defects that have achieved similar mechanical attributes as native intact tendon.…”