The effect of polystyrene sodium sulfonate grafting on polyethylene terephthalate artificial ligaments on in vitro mineralisation and in vivo bone tissue integration

Abstract

This study investigates the impact of polystyrene sodium sulfonate (PolyNaSS) grafting onto the osseointegration of a polyethylene terephthalate artificial ligament (Ligament Advanced Reinforcement System, LARS™) used for Anterior Cruciate Ligament (ACL). The performance of grafted and non-grafted ligaments was assessed in vitro by culturing human osteoblasts under osteogenic induction and this demonstrated that the surface modification was capable of up-regulating the secretion of ALP and induced higher level of mineralisation as measured 6 weeks post-seeding by Micro-Computed Tomography. Grafted and non-grafted LARS™ were subsequently implanted in an ovine model for ACL reconstruction and the ligament-to-bone interface was evaluated by histology and biomechanical testing 3 and 12 months post-implantation. The grafted ligaments exhibited more frequent direct ligament-to-bone contact and bone formation in the core of the ligament at the later time point than the nongrafted specimens, the grafting also significantly reduced the fibrous encapsulation of the ligament 12 months post-implantation. However, this improved osseo-integration was not translated into a significant increase in the biomechanical pull-out loads. These results provide evidences that PolyNaSS grafting improved the osseo-integration of the artificial ligament within the bone tunnels. This might positively influence the outcome of the surgical reconstructions, as higher ligament stability is believed to limit micro-movement and therefore permits earlier and enhanced healing.

Grafting titanium nitride surfaces with sodium styrene sulfonate thin films

“…7,[24][25][26][27] The XPS surface elemental composition of pNaSS grafted surface [ Table I and Fig. 2(c)] showed the presence of sulfur and sodium, which are unique to the NaSS molecules, providing evidence of the successful grafting of pNaSS from the MPS modified surface.…”

“…[18][19][20][21][22] It has already been shown that polymers bearing appropriate chemical functions can modulate cell attachment, spreading, and activity on these bioactive polymers. [23][24][25][26] The distributions of ionic groups along with the macromolecular chains create active sites, which can interact with extracellular proteins, such as fibronectin, implicated in cell response. [23][24][25][26][27] Given the benefits of titanium nitride in terms of wear resistance and corrosion protection, grafting of a bioactive polymer from the titanium nitride surface is a potentially useful way to combine the benefits of titanium nitride with the grafted bioactive polymer.…”

Silk‐Based Biomaterials in Biomedical Textiles and Fiber‐Based Implants

“…Usually, silk fibers in monofilament, multifilament and non-woven formats are woven, knitted and braided or combined into “wire-rope” scaffolds with a micro-porous structure [18–21, 127, 129, 130] . SBBs nerve scaffolds prepared from non-woven or fiber enhanced methods demonstrated good biocompatibility and appropriate mechanical performance in vitro and in vivo [131, 132] .…”

Surface initiated atom transfer radical polymerization grafting of sodium styrene sulfonate from titanium and silicon substrates

“…Increased proliferation and adhesion of fibroblasts, 6 MG63 osteoblast-like cells, [7][8][9] and human mandibular osteoblasts 10 have been shown in vitro on sodium styrene sulfonate (NaSS) modified Ti and poly(ethylene terephthalate) surfaces. Promising results have also been obtained in vivo for the same surfaces.…”

“…Promising results have also been obtained in vivo for the same surfaces. [10][11][12] Since the foreign body response begins with nonspecific protein adsorption, and cell function on surfaces is mediated by adsorbed proteins, 3 poly(NaSS) (pNaSS) grafted implants are hypothesized to preferentially adsorb certain plasma proteins in an orientation and conformation that modulates the foreign body response and promotes formation of new bone. Our ultimate goal is to test this hypothesis.…”