The purpose of this study was to investigate whether hydroxyapatite (HAp) coating could induce polyethylene terephthalate (PET) artificial ligament graft osseointegration in the bone tunnel. Twenty-four New Zealand white rabbits underwent artificial ligament graft transplantation in bilateral proximal tibia tunnels. One limb was implanted with HAp-coated PET graft, and the contralateral limb was implanted with non-HAp-coated PET graft as control. The rabbits were randomly sacrificed at four and eight weeks after surgery. The loads to failure of the experimental group at eight weeks were significantly higher than those of the control group (p = 0.0057). Histologically, application of HAp coating induced new bone formation between graft and bone at eight weeks compared with the controls. Real-time polymerase chain reaction examination revealed significantly elevated messenger ribonucleic acid expression levels of osteopontin and collagen I in the grafts of the HAp group compared with the controls at four weeks (p < 0.05). The study has shown that HAp coating on the PET artificial ligament surface has a positive effect in the induction of artificial ligament osseointegration within the bone tunnel.

Purpose The aim of the study was to investigate whether a bioactive glass (BG) coating on the polyethylene terephthalate (PET) artificial ligament could enhance graft osseointegration by promoting bone regeneration at the interface between PET graft and bone tunnel. Methods Thirty New Zealand white rabbits underwent artificial ligament graft transplantation in proximal tibial tunnels bilaterally. One limb was implanted with a 58S BGcoated PET graft, and the contralateral limb was implanted with a non-BG-coated PET graft as a control. The rabbits were randomly sacrificed at three, six and 12 weeks after surgery for biomechanical and histological examinations. Results The maximum load to failures of the BG-coated experimental group were significantly higher than those of the control group at 12 weeks (p=0.0051). Histologically, at 12 weeks, the BG-coated PET graft induced great new bone formation between graft and host bone, and the average graft-bone interface width of the BG group became significantly lower than that of the control group. Furthermore, the BG coating on the ligament graft surface also stimulated greater expression of bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF) around the graft in vivo compared to the control group at three weeks (p<0.05).Conclusions This study has shown that a BG coating on the PET artificial ligament surface has a positive effect in the induction of artificial ligament osseointegration within the bone tunnel.

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Surface coating with an organic layer-by-layer self-assembled template of chitosan and hyaluronic acid on a poly(ethylene terephthalate) (PET) artificial ligament was designed for the promotion and enhancement of graft-to-bone healing after artificial ligament implantation in a bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells supported the hypothesis that the layer-by-layer coating of chitosan and hyaluronic acid could promote the cell compatibility of grafts and could promote osteoblast proliferation. A rabbit extra-articular tendon-to-bone healing model was used to evaluate the effect of this kind of surface-modified stainless artificial ligament in vivo. The final results proved that this organic compound coating could significantly promote and enhance new bone formation at the graft-bone interface histologically and, correspondingly, the experimental group with coating had significantly higher biomechanical properties compared with controls at 8 weeks (P < 0.05).

Driven by the synergistic-directing effect of the lacunary fragments, [B-α-GeW9O34]10– and [B-α-GeW11O39]8–, an unprecedented hepta-Zr-substituted polyoxometalate (POM) assembly K2Na6H10(Hpy)3[SbZr7O6(OH)4(B-α-GeW9O34)2(B-α-GeW11O39)2]·28H2O (1) was made under hydrothermal condition and structurally characterized. Of which, a unique hepta-Zr cluster, [SbZr7O6(OH)4]15+ core, was built by two trilacunary [B-α-GeW9O34]10– fragments and two monolacunary [B-α-GeW11O39]8– fragments and further arranged in a mode of a vertical cross and formed a pseudo-tetrahedron geometry. Compound 1 features the first Zr7-cluster-substituted POM. Moreover, 1 is an effective heterogeneous catalyst for the catalytic oxidation of sulfides into the corresponding sulfones with H2O2, manifesting distinguished conversion, excellent yield, and desired recyclability.

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The ideal artificial ligament graft should have favorable biocompatibility to facilitate cell adhesion, proliferation, and collagen regeneration. In this present study, surface modification was performed on a poly(ethylene terephthalate) (PET) artificial ligament graft by layer-by-layer (LBL) self-assembly coating of hyaluronic acid (HA) and chitosan (CS). The surface characterization of the ligament was examined using scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray spectroscopy. The results of in vitro culturing of human foreskin fibroblast cells supported the hypothesis that the LBL coating of CS-HA could promote the cell proliferation and adhesion on the sheets. A rabbit medical collateral ligament reconstruction model was used to evaluate the effect of this LBL coating in vivo. The final results proved that this LBL coating could significantly promote and enhance new collagen formation among the graft fibers. On the basis of these results, we conclude that such CS-HA assembly coating could enhance PET graft biocompatibility in vitro and in vivo, and a CS-HA-coated PET graft has considerable potential as a desirable substitute for ligament reconstruction.