1. |
- Grandfield, Kathryn, 1986-, et al.
(författare)
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Ultrastructural characterisation of the hydroxyapatite–coated pedicle screw and human bone interface
- 2012
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Ingår i: International Journal of Nano and Biomaterials. - 1752-8933 .- 1752-8941. ; 4:1, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- The early fixation of pedicle screws is crucial for improving spinal stabilisation. Firm and immediate fixation between pedicle screws and bone prevents aseptic loosening and implant failure. Coating with hydroxyapatite is a possible method to improve the fixation of metallic implants in bone. In this study, scanning transmission electron microscopy (STEM) has been used to investigate the ultrastructure of the plasma–sprayed hydroxyapatite coating and human bone interface in detail. Focused ion beam sample preparation also enabled the investigation of the bone–lacunae interface. An intimate contact and elemental analysis between bone and HA coatings suggests bioactive fixation. Therefore, coating with hydroxyapatite leads to enhanced biocompatibility at the ultrastructural level and may lead to improved early and long–term fixation of pedicle screws.
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2. |
- Åberg, Jonas, 1982-, et al.
(författare)
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In vitro and in vivo evaluation of an injectable premixed calcium phosphate cement : cell viability and immunological response from rat
- 2010
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Ingår i: International Journal of Nano and Biomaterials. - 1752-8941. ; 3:3, s. 203-221
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Tidskriftsartikel (refereegranskat)abstract
- By using premixed calcium phosphate cement (CPC) the handling properties of the cement are drastically improved, which is a challenge for traditional injectable CPC. In this article, a premixed acidic CPC has been compared to a conventional water mixed brushite cement to evaluate whether the premixed concept affects the biological response. The cements were evaluated regarding the pH-variation in simulated body fluid (SBF). Further, the biocompatibility of the cement with human mesenchymal stem cells (MSC) was studied in vitro and eventual inflammation properties studied in vivo, after subcutaneous material injections in rats. A larger pH decrease was seen for the conventional cement than the premixed cement in SBF. For both materials, > 90% of the MSC remained alive in vitro. No systemic or macroscopic inflammation was detected, only a mild microscopic inflammation was detected around both materials. In addition to the handling benefit of premixed cements compared to conventional water mixed CPC, the premixed CPC in the present study demonstrated high and in comparison to conventional CPC comparable biocompability, both in vitro and in vivo.
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3. |
- Almqvist, Sofia, 1980, et al.
(författare)
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Amelogenins promote an alternatively activated macrophage phenotype in vitro.
- 2011
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Ingår i: International Journal of Nano and Biomaterials (IJNBM). - 1752-8933. ; 3:3, s. 282-298
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Amelogenins are extracellular matrix proteins used for the topical treatment of chronically inflamed tissues. The influence of amelogenins on human monocyte-derived macrophages was studied by measuring the concentrations of cytokines in culture supernatants. The interactions of cells and protein aggregates were visualised by transmission electron microscopy. The amelogenin treatment of macrophages increased several pro- and anti-inflammatory cytokines, including alternative macrophage activation marker AMAC-1 (p < 0.001) and vascular endothelial growth factor (VEGF; p < 0.001). The levels were independent of cytochalasin B, although amelogenin aggregates were ingested by macrophages. Amelogenin effect was compared with that of tyrosine-rich amelogenin peptide, which apart from augmented VEGF levels (p < 0.05), had no significant influence on the other cytokines analysed. In conclusion, amelogenins increased the macrophage release of key cell mediators involved in tissue repair. The effect was independent of phagocytosis, implying a receptor-mediated signal. The markedly increased levels of AMAC-1 suggest that amelogenins promote a reparative macrophage phenotype.
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