Experimental model of osteonecrosis of the jaw associated to bisphosphonates (ONJBPs) in ewes chronically treated with high doses of zoledronic acid (original) (raw)
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Journal of Materials Science: Materials in Medicine, 2002
The present study describes a methodology to produce bioactive coatings on the surface of starch based biodegradable polymers or other polymeric biomaterials. As an alternative to the more typical bioactive glass percursors, a sodium silicate gel is being employed as a nucleating agent, for inducing the formation of a calcium-phosphate (Ca-P) layer. The method has the advantage of being able to coat ef®ciently both compact materials and porous 3D architectures aimed at being used on tissue replacement applications and as bone tissue engineering scaffolds. This treatment is also very effective in reducing the incubation periods, being possible to observe the formation of an apatite-like layer, only after 6 h of immersion in a simulated body¯uid (SBF). The in¯uence of the SBF concentration on the formation of the apatite coating was also studied. The apatite coatings formed under different conditions were analyzed and compared in terms of morphology, chemical composition and structure. After the ®rst days of SBF immersion, the apatite-like ®lms exhibit the typical cauli¯ower like morphology. With increasing immersion times, these ®lms exhibited a partially amorphous nature and the Ca/P ratios became very closer to the value attributed to hydroxyapatite (1.67). The obtained results are very promising for pre-calcifying bone tissue engineering scaffolds. Therefore, in order to study cell behavior and response to these apatite coatings, adhesion, morphology, and proliferation of a human osteoblast cell line (SaOS-2) was also analyzed after being cultured in the coatings formed after 15 days of immersion in SBF. Results indicate a good correlation between crystallinity of the apatite like coatings formed in these conditions and respective cell spreading and morphology. In general, higher cell proliferation was observed for higher crystalline Ca-P coatings.
Coatings, 2019
There is an increased interest in developing biocomposite implants with high biocompatibility in order to be used as grafts or prostheses in orthopedic surgery. The purpose of the study was to determine the biocompatibility of titanium implants coated with synthesized hydroxyapatite-alendronate composites. The implants were obtained using Matrix Assisted Pulsed Laser Evaporation technique (MAPLE). The hydroxyapatite-alendronate composites were synthesized using the wet precipitation method. Immunofluorescence microscopy showed that composites support mesenchymal stem cells (MSCs) adhesion. Bone cells as well as human MSCs adhere to hydroxyapatite (HA)-based thin films obtained by matrix assisted laser deposition onto titanium. Alendronate doping into the films increased the number of cell-biomaterial focal points as compared to HA only. Thus, the synthesis of hydroxyapatite-alendronate composite (HA-AL) may be considered a viable solution for including the bisphosphonate on the surface of metallic prosthetic components used in orthopedics.
Bioactive materials interact with cells and modulate their characteristics which enables the generation of cell-based products with desired specifications. However, their evaluation and impact are often overlooked when establishing a cell therapy manufacturing process. In this study, we investigated the role of different surfaces for tissue culture including, untreated polystyrene surface, uncoated Cyclic Olefin Polymer (COP) and COP coated with collagen and recombinant fibronectin. It was observed that hMSCs expanded on COP-coated plates with different bioactive materials resulted in improved cell growth kinetics compared to traditional polystyrene plates and uncoated COP non-coated plates. The doubling time obtained was 2.78 and 3.02 days for hMSC seeded in COP plates coated with collagen type I and recombinant fibronectin respectively, and 4.64 days for cells plated in standard polystyrene treated plates. Metabolite analysis reinforced the findings of the growth kinetic studies, ...
Journal of Biomedical Materials Research Part A, 2005
Titanium (Ti) surface was coated with hydroxyapatite (HA) films via the sol-gel method. The coating properties, such as crystallinity and surface roughness, were controlled and their effects on the osteoblast-like cell responses were investigated. The film crystallinity was controlled with different heat treatment temperatures (400, 500, and 600°C): Also the surface roughness was changed by using different heating rates (1 and 50°C/min). The obtained sol-gel films had a dense and homogeneous structure with a thickness about 1 m. The film heat-treated at higher temperature had enhanced crystallinity (600 Ͼ 500 Ͼ Ͼ 400°C), while retaining similar surface roughness. When heattreated rapidly (50°C/min), the film became quite rough, with roughness parameters being much higher (4 -6 times) than that obtained at a low heating rate (1°C/min). The dissolution rate of the film decreased with increasing crys-tallinity (400 Ͼ Ͼ 500 Ͼ 600°C), and the rougher film had slightly higher dissolution rate. The attachment, proliferation, and differentiation behaviors of human osteosarcoma HOS TE85 cells were affected by the properties of the films. On the films with higher crystallinity (heat treated over 500°C), the cells attached and proliferated well and expressed alkaline phosphatase (ALP) and osteocalcin (OC) to a higher degree as compared to the poorly crystallized film (heat treated at 400°C). On the rough film, the cell attachment was enhanced, but the ALP and OC expression levels were similar as compared to the smooth films.
Journal of Materials Science: Materials in Medicine, 2013
The hypothesis for this study was that there is no difference in mesenchymal stem cells (MSCs) proliferation and osteogenic differentiation between calciumphosphate (CaP) coatings with different crystal size deposited on different topographic surfaces of metal discs. Polished (P) and sand-blasted (SB) tantalum and TiAl6V4 discs were CaP coated by three methods-biomimetic (BioM), electrochemical at 20 mA/cm 2 and at 6.5 mA/ cm 2 -and cultured with MSCs. At days 4, 7 and 14, cell proliferation-alamarBlue Ò activity and DNA quantification-and differentiation down the osteogenic lineage-ALP activity normalised per amount of DNA and SEM (morphology)-were analysed. Results showed that MSCs proliferated more when cultured on the nano-sized BioM coatings compared to uncoated and electrochemically coated discs. MSCs also proliferated more on P surfaces than on SB and or electrochemical coatings. All the coatings induced osteogenic differentiation, which was greater on electrochemical coatings and SB discs.
Journal of Biomedical Materials Research Part A, 2006
The aim of this study was to evaluate the osteogenic properties of magnetron sputtered dicalcium pyrophaosphate (DCPP) and hydroxylapatite (HA) coatings. Therefore, DCPP and HA coatings were deposited on grit-blasted titanium discs. The substrates were used as-prepared or received an additional heat treatment which changed the amorphous coating structure to a crystalline structure. Subsequently, rat bone marrow stromal cells were cultured for 1-24 days on the various substrates. DNA and alkaline phosphatase activity was determined after 1, 3, 5, 8, and 12 days of incubation. Osteocalcin expression was evaluated after 8, 12, 16, and 24 days of incubation. Scanning electron microscopical analysis of cell morphology and coating characteristics was done after 8 and 16 days of incubation. All assays were done in duplicate and in each assay all specimens were present in fourfold. Results demonstrated that the cells did not proliferate and differentiate on all amorphous coatings. SEM revealed that the amorphous coatings showed significant dissolution. On the crystalline DCPP and HA coatings an increase in DNA and alkaline phosphatase activity was seen starting at day 8 of incubation. Osteocalcin expression on the crystalline coatings started to increase at day 16 of incubation. SEM showed that the growth and differentiation of the cells was associated with extensive collagen fiber formation and surface mineralization in the form of globular accretions. Further, statistical testing revealed that proliferation and differentiation of the rat bone marrow stromal cells started significantly earlier on the crystalline HA coatings than that on the crystalline DCPP coatings. These results demonstrate that the rat bone marrow stromal cells proliferated and differentiated only on crystalline magnetron sputtered DCPP as well as HA coatings, which warrants the further in vivo analysis of the bone healing supporting properties of these coatings.
Interaction of human mesenchymal stem cells with osteopontin coated hydroxyapatite surfaces
Colloids and Surfaces B: Biointerfaces, 2010
In vitro studies of the initial attachment, spreading and motility of human bone mesenchymal stem cells have been carried out on bovine osteopontin (OPN) coated hydroxyapatite (HA) and gold (Au) model surfaces. The adsorption of OPN extracted from bovine milk was monitored by the quartz crystal microbalance with dissipation (QCM-D) and the ellipsometry techniques, and the OPN coated surfaces were further investigated by antigen-antibody interaction. It is shown that the OPN surface mass density is significantly lower and that the number of antibodies binding to the resulting OPN layers is significantly higher on the HA as compared to the Au surfaces. The initial attachment, spreading and motility of human mesenchymal stem cells show a larger cell area, a faster arrangement of vinculin in the basal cell membrane and more motile cells on the OPN coated HA surfaces as compared to the OPN coated Au surfaces and to the uncoated Au and HA surfaces. These in vitro results indicate that there may be great potential for OPN coated biomaterials, for instance as functional protein coatings or drug delivery systems on orthopaedic implants or scaffolds for tissue-engineering.
The response of osteoblasts to nanocrystalline silicon-substituted hydroxyapatite thin films
Biomaterials, 2006
Magnetron co-sputtering has been employed to fabricate thin nanocrystalline coatings of silicon-substituted hydroxyapatite (SiHA) of different Si compositions: 0.8 wt%, 2.2 wt%, and 4.9 wt%. A human osteoblast-like (HOB) cell model was used to study the long-term interaction between the HOB cells and coatings in vitro. Results showed that the number of cells growing on all coated titanium (Ti) samples were statistically significantly higher than on uncoated Ti. In addition, HOB cells growing on all SiHA surfaces displayed enhanced cell spreading, with extensive extracellular matrix synthesis. DNA staining revealed normal phenotype nuclear morphology for HOB cells, with several dense chromosomes surrounded by a periphery of intact nuclear membrane. Furthermore, immunofluorescent staining indicated that cells showed improved adhesion on the coated surfaces with increasing Si content, developing mature cytoskeletons with numerous distinct and well-defined actin stress fibres in the cell membranes. Results also demonstrated that the bone mineralisation process was greatest in the presence of the highest Si level (4.9 wt%). However, at very early culturing time point, cells did not attach so readily on the surface of this coating due to rapid dissolution. Thus, this work suggests that a Si content of 2.2 wt% may be the optimum loading to improve the bioactive property of HA thin films. r
Initial Attachment of Osteoblast-Like Cells on Functionalized Surfaces Coated with Calcium Phosphate
Key Engineering Materials, 2006
Tissue engineering techniques which combine synthetic grafts with molecules and cells are considered as viable long term solutions for bone tissue repair and reconstruction procedures. The self SAM technology enables modeling of surface functional groups on biomaterials, while the concept of ion-selective precipitation reaction causes formation of Ca-P coating on these functionalized surfaces. Hydrophilic surfaces such as -COOH or -OH end groups have very powerful induction capability for the heterogeneous nucleation of hydroxyapatite-like layer, while nucleation could be prohibited on an -NH 2 -terminated surface. Using the SAM technique we grafted three different organosilanes onto silicon wafers to yield -NH 2 , -COOH and -OH functionalized surfaces respectively. The surfaces were characterized by contact angle measurements, ellipsometry, FTIR, SEM/EDX and RBS. Ca-P coating was formed on the SAMs by immersion in a simulated physiological fluid (pH 7.4, at 37 o C). FTIR showed dependence of the morphology of the Ca-P coating on both the type of surface functionality and on the duration of coating. The spectrum exhibited P-O and C-O absorption bands characteristic of a carbonated calcium hydroxyapatite with stronger P-O bands on -OH surface. MC3T3-E1 osteoblast-like cells were used in bioassays to study the effect of the end groups on the initial cellular attachment and alkaline phosphatase expression on Ca-P coated surfaces. Cell assays showed increased cellular attachment on the Ca-P coated-OH SAM, after cells were seeded for 1h, compared to the -NH 2 and -COOH-terminated surfaces, while up to 5x alkaline phosphatase activity was shown on Ca-P coated surfaces. At a low temperature therefore, the end groups of SAMs act as effective nucleation sites to induce formation of a biomimetic apatite coating, in a one-step biomineralization process. The most potent apatite forming surface, the -OH SAM surface, demonstrates that surface -OH groups are important to induce bone bioactive behavior at surfaces.