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Sökning: L773:1549 3296 OR L773:1552 4965

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1.
  • Andersson, Ann-Sofie, et al. (författare)
  • Cell adhesion on supported lipid bilayers
  • 2003
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 64:4, s. 622-9
  • Tidskriftsartikel (refereegranskat)abstract
    • The cell and protein repellent properties of supported phospholipid bilayer (SPB) membranes were investigated. The SPBs were prepared by vesicle adsorption on SiO(2) surfaces. The vesicles of phosphatidylcholine fuse and rupture, and form a supported bilayer covering the surface. We carried out cell culture experiments on several surfaces, including SPBs, using two types of epithelial cells to address the cell adhesional properties. The Quartz Crystal Microbalance Dissipation (QCM-D) technique was used to monitor the SPB formation and subsequent protein adsorption. Neither cell type adhered or proliferated on SiO(2) surfaces coated with SPBs, whereas both cell types adhered and proliferated on the three control surfaces of SiO(2), tissue culture glass, and TiO(2). The QCM-D measurements showed that about two orders of magnitude less mass adsorbed on a SPB surface compared to a TiO(2) surface, from serum-containing media (10% fetal bovine serum). The reduced adsorption on the SPB is a likely explanation for the nondetectable epithelial cell adhesion on the SPB surface. Biomembranes are therefore attractive candidate systems to achieve alternating cell-resistant and cell-interacting regions on surfaces, by including specific cell-binding proteins in the latter regions.
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2.
  • Andersson, Jessica, et al. (författare)
  • Behavior of human chondrocytes in engineered porous bacterial cellulose scaffolds
  • 2010
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 94A:4, s. 1124-1132
  • Tidskriftsartikel (refereegranskat)abstract
    • Regeneration of articular cartilage damage is an area of great interest due to the limited ability of cartilage to self-repair. The latest cartilage repair strategies are dependent on access to biomaterials to which chondrocytes can attach and in which they can migrate and proliferate, producing their own extracellular matrix. In the present study, engineered porous bacterial cellulose (BC) scaffolds were prepared by fermentation of Acetobacter xylinum (A. xylinum) in the presence of slightly fused wax particles with a diameter of 150-300 mu m, which were then removed by extrusion. This porous material was evaluated as a scaffold for cartilage regeneration. Articular chondrocytes from young adult patients as well as neonatal articular chondrocytes were seeded with various seeding techniques onto the porous BC scaffolds. Scanning electron microscopy (SEM) analysis and confocal microscopy analysis showed that cells entered the pores of the scaffolds and that they increasingly filled out the pores over time. Furthermore, DNA analysis implied that the chondrocytes proliferated within the porous BC. Alcian blue van Gieson staining revealed glycosaminoglycan (GAG) production by chondrocytes in areas where cells were clustered together. With some further development, this novel biomaterial can be a suitable candidate for cartilage regeneration applications.
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3.
  • Andersson, Marcus, 1975, et al. (författare)
  • Effect of molecular mobility of polymeric implants on soft tissue reactions: An in vivo study in rats
  • 2008
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 84A:3, s. 652-660
  • Tidskriftsartikel (refereegranskat)abstract
    • Although numerous different polymers are used as implants or otherwise studied for many other biotechnical applications, there is a lack of basic models that correlate polymer characteristics with foreign body reactions. This study aims at developing one such model by systematically studying surface molecular mobility of polymeric implants in soft tissues in vivo. Changing the length of the alkyl side chain of poly(alkyl methacrylates) (PAMAs), provides an interesting opportunity to study the surface molecular mobility with minimal changes of the hydrophobicity of the surface. Thus, in this study three different PAMAs, with increasingly surface mobility; poly (isobutyl methacrylate) (PIBMA), poly(butyl methacrylate) (PBMA), and poly(lauryl methacralate) (PLMA) along with pure titanium (Ti) substrates were implanted in the dorsum of Sprague-Dawley rats. Inflammatory cell recruitment, cell adhesion, and cytokine release were studied after 1, 3, and 28 days of implantation. Total number of inflammatory cells in the exudate was measured but no correlation between surface mobility and cell recruitment where found. However, the number of surface associated cells where significantly lower on the surfaces with high molecular mobility (PLMA and PBMA). The histological evaluation performed after 28 days revealed thicker fibrous capsule and a higher number of blood vessels on the low molecular mobility surface (PIBMA). After 28 days the cell activity was higher on the high molecular mobility surfaces (PLMA and PBMA) compared with PIBMA, based on the cytokine release. None of the surfaces induced any significant cell-death. On the basis of the results of this study we conclude that there is a significant difference in biological response to surfaces with different in molecular mobility. This might affect the wound healing process and the biocompatibility of biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007 -------------------------------------------------------------------------------- Received: 13 March 2006; Revised: 15 December 2006; Accepted: 29 January 2007 Digital Object Identifier (DOI) 10.1002/jbm.a.31389 About DOI
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4.
  • Arruda, Thiago, et al. (författare)
  • Early healing in alveolar sockets grafted with titanium granules. An experimental study in a dog model.
  • 2013
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 101A:7, s. 1971-1976
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present study was to evaluate the effect of the placement of titanium granules in fresh extraction sockets on early bone formation. The mesial roots of the third maxillary premolars of five adult beagle dogs were removed. On one side of the maxilla (Test group) the fresh extraction socket was grafted with titanium granules, while the contra-lateral socket was left non-grafted (Control group). After 1 month of healing, the dogs were euthanized and biopsies were obtained. The healing tissues were described, and histometric measurements were performed to obtain the percentage area occupied by connective tissue, new mineralized bone, bone marrow, and biomaterial particles. After 1 month of healing the findings from the histological examination revealed the titanium graft to be well incorporated into the provisional connective tissue or newly formed woven bone. The histometric measurements showed, however, that less mineralized bone was formed in the Test group than in the Control group. The present study suggests that the use of titanium granules in fresh extraction sockets was conducive to new bone formation. The graft of titanium granules seems, however, to delay the early phase of the healing process. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
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5.
  • Barkarmo, Sargon, et al. (författare)
  • Nano-hydroxyapatite-coated PEEK implants : a pilot study in rabbit bone
  • 2013
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:2, s. 465-471
  • Tidskriftsartikel (refereegranskat)abstract
    • Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.
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6.
  • Bergman, Kristoffer, et al. (författare)
  • Injectable cell-free template for bone-tissue formation
  • 2009
  • Ingår i: Journal of Biomedical Materials Research-Part A. - : Wiley Periodicals, Inc. - 1549-3296 .- 1552-4965. ; 91A:4, s. 1111-1118
  • Tidskriftsartikel (refereegranskat)abstract
    • Here we present a novel injectable hydrogel which forms a template for de novo formation of bone tissue. Hydrogel formation takes place in situ in less than 1 min by the cross-linking of multifunctional hyaluronic acid and polyvinyl alcohol derivatives. Endogenous cells are recruited in vivo by incorporating bone morphogenetic protein-2 (BMP-2), a powerful promoter for osteogenic differentiation. The hydrogel was evaluated in vitro by performing a cell viability test and a release study and in vivo by a rat ectopic model. Examination by X-ray, microcomputed tomography, and histology revealed a significant bone formation at the target site for gels containing BMP-2, and a complete degradation was observed for gels without BMP-2 four weeks after injection. There were no signs of inflammation or foreign body response in either group and we believe that this system has the potential as an off-the-shelf injectable to be used where bone tissue is needed.
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7.
  • Bergstrand, Anna, 1974, et al. (författare)
  • Comparison of PEI-PEG and PLL-PEG Copolymer Coatings on the Prevention of Protein Fouling
  • 2009
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:3, s. 608-615
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of surface charge on the protein resistance of adsorbed layers of poly(ethylene imine)-[g]poly(ethylene glycol), PEI-PEG, and poly(L-lysine)-[g]poly(ethylene glycol), PLL-PEG, was studied. Mixed and monofunctional self-assembled monolayers, SAMs, on gold were obtained by adsorption of 16-mercapto-1-hexadecanoic acid and 16-mercapto-1-hexadecanol. The surface charge was systematically varied by changing the ratio of the two alkanethiols. The graft copolymers PEI-PEG and PLL-PEG were adsorbed at the SAMs and tested for resistance towards human serum albumin and fibrinogen. The adsorbed amount of copolymers increased with increasing negative surface charge. However, the best protein resistance was found at an intermediate surface charge. The PLL-PEG covered Surfaces showed better protein resistance than the PEI-PEG covered surfaces. Thus, this work demonstrates that an adsorbed layer of PEG-grafted PEI and, in particular, PEG-grafted PLL is efficient in preventing protein adsorption when there is charge neutralization between the copolymer and the underlying surface.
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8.
  • Bexborn, Fredrik, et al. (författare)
  • Hirudin versus heparin for use in whole blood in vitro biocompatibility models
  • 2009
  • Ingår i: Journal of Biomedical Materials Research. Part A. - Hoboken, NJ, US : John Wiley & Sons Inc. - 1549-3296 .- 1552-4965. ; 89A:4, s. 951-959
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Heparin has traditionally been a widely used anticoagulant in blood research, but has been shown to be inappropriate for work with the complement system because of its complement-interacting properties. In this work, we have compared the effects of heparin with those of the specific thrombin inhibitor hirudin on complement and blood cells in vitro. Methods: Whole blood collected in the presence of hirudin (50 µg/mL) or heparin (1 IU/mL) was incubated in the slide chamber model. The plasma was analyzed for complement activation markers C3a and sC5b-9, and the polyvinylchloride test slides were stained for adhering cells. The integrity of the complement system was tested by incubating serum and hirudin-treated plasma in the presence of various activating agents.Results: In contrast to heparin, the addition of hirudin generally preserved the complement reactivity, and complement activation in hirudin plasma closely resembled that in normal serum. Importantly, immunochemical staining of surface-bound cells demonstrated the inducible expression of tissue factor on bound monocytes from hirudin-treated blood, an effect that was completely abolished in heparin-treated blood.Conclusion: Our results indicate that hirudin as an anticoagulant produces more physiological conditions than heparin, making hirudin well-suited for in vitro studies, especially those addressing the regulation of cellular processes.
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9.
  • Bjursten, Lars Magnus, et al. (författare)
  • Titanium dioxide nanotubes enhance bone bonding in vivo.
  • 2010
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 92:3, s. 1218-24
  • Tidskriftsartikel (refereegranskat)abstract
    • Implant topography is critical to the clinical success of bone-anchored implants, yet little is known how nano-modified implant topography affects osseointegration. We investigate the in vivo bone bonding of two titanium implant surfaces: titanium dioxide (TiO(2)) nanotubes and TiO(2) gritblasted surfaces. In previous in vitro studies, the topography of the TiO(2) nanotubes improved osteoblast proliferation and adhesion compared with gritblasted titanium surfaces. After four weeks of implantation in rabbit tibias, pull-out testing indicated that TiO(2) nanotubes significantly improved bone bonding strength by as much as nine-fold compared with TiO(2) gritblasted surfaces. Histological analysis confirmed greater bone-implant contact area, new bone formation, and calcium and phosphorus levels on the nanotube surfaces. It is anticipated that further studies will contribute to a better understanding of the effect of implant nanotopography on in vivo bone formation and bonding strength.
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10.
  • Bloch, K, et al. (författare)
  • Functional activity of insulinoma cells (INS-1E) and pancreatic islets cultured in agarose cryogel sponges
  • 2005
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 75A:4, s. 802-809
  • Tidskriftsartikel (refereegranskat)abstract
    • Here, we describe the preparation, structure, and properties of cryogel sponges, which represent a new type of macroporous biomaterial for tissue engineering. Cryogels were produced through freeze-thawing techniques, either from agarose alone or from agarose with grafted gelatin. The aim of this study was to evaluate agarose cryogel sponges as scaffolds for Culturing both isolated pancreatic islets and insulinoma cells (INS-IE). In order to evaluate the effect of cell entrapment in artificial scaffolds, cell function reflected by insulin secretion and content was studied in cells cultivated for a 2-week period either in Culture plastic plates or in cryogel sponge disks. Our results show that tumor-derived INS-1E cells grown either on plastic or on cryogels do not differ in their proliferation, morphology, insulin release, and intracellular insulin content. However, isolated pancreatic islets cultivated on cryogels sponge show 15-fold higher basal insulin secretion at 3.0 mM glucose than islets cultivated on plastic plates and fail to respond to stimulation with 16.7 mM glucose. In addition, these islets have about 2-fold lower insulin content compared to those grown in plastic plates. It is possible that the cell dysfunction noted in these in vitro experiments is due to the effect of the limited oxygen supply to the islets cultivated in cryogel sponge. Further in vivo Studies are needed to clarify the nature of such an observation since according to previous reports, agarose and gelatin induce new vessel formation supporting enhanced oxygen supply. (c) 2005 Wiley Periodicals, Inc.
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11.
  • Bolgen, Nimet, et al. (författare)
  • Tissue responses to novel tissue engineering biodegradable cryogel scaffolds: An animal model
  • 2009
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 91A:1, s. 60-68
  • Tidskriftsartikel (refereegranskat)abstract
    • Biodegradable macroporous cryogels with highly open and interconnected pore structures were produced from dextran modified with oligo L-lactide bearing hydroxyethylmethacrylate (HEMA) end groups in moderately frozen solutions. Tissue responses to these novel scaffolds were evaluated in rats after dorsal subcutaneous implantation, iliac submuscular implantation, auricular implantation, or in calvarial defect model. In no case, either necrosis or foreign body reaction was observed during histological studies. The cryogel scaffolds integrated with the surrounding tissue and the formation of a new tissue were accompanied with significant ingrowth of connective tissue cells and new blood vessels into the cryogel. The tissue responses were significantly lower in auricular and calvarial implantations when compared with the subcutanous and the submuscular implantations. The degradation of the scaffold was slower in bone comparing to soft tissues. The biodegradable cryogels are highly biocompatible and combine extraordinary properties including having soft and elastic nature, open porous structure, and very rapid and controllable swelling. Therefore, the cryogels could be promising candidates for further clinical applications in tissue regeneration. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 91 A: 60-68, 2009
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12.
  • Cairns, Marie-Louise, et al. (författare)
  • The potential of electron beam radiation for simultaneous surface modification and bioresorption control of PLLA.
  • 2012
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 100:9, s. 2223-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioresorbable polymers have been widely investigated as materials exhibiting significant potential for successful application in the fields of tissue engineering and drug delivery. Further to the ability to control degradation, surface engineering of polymers has been highlighted as a key method central to their development. Previous work has demonstrated the ability of electron beam (e-beam) technology to control the degradation profiles and bioresorption of a number of commercially relevant bioresorbable polymers (poly-l-lactic acid (PLLA), L-lactide/DL-lactide co-polymer (PLDL) and poly(lactic-co-glycolic acid (PLGA)). This work investigates the further potential of e-beam technology to impart added biofunctionality through the manipulation of polymer (PLLA) surface properties. PLLA samples were subjected to e-beam treatments in air, with varying beam energies and doses. Surface characterization was then performed using contact angle analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy. Results demonstrated a significant increase in surface wettability post e-beam treatment. In correlation with this, XPS data showed the introduction of oxygen-containing functional groups to the surface of PLLA. Raman spectroscopy indicated chain scission in the near surface region of PLLA (as predicted). However, e-beam effects on surface properties were not shown to be dependent on beam energy or dose. E-beam irradiation did not seem to affect the surface roughness of PLLA as a direct consequence of the treatment.
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13.
  • Carville, N. Craig, et al. (författare)
  • Biocompatibility of ferroelectric lithium niobate and the influence of polarization charge on osteoblast proliferation and function
  • 2015
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley and Sons. - 1549-3296 .- 1552-4965. ; 103:8, s. 2540-2548
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, the influence of substrate surface charge on in vitro osteoblast cell proliferation on ferroelectric lithium niobate (LN) crystal surfaces is investigated. LN has a spontaneous polarization along the z-axis and is thus characterized by positive and negative bound polarization charge at the +z and -z surfaces. Biocompatibility of LN was demonstrated via culturing and fluorescence imaging of MC3T3 osteoblast cells for up to 11 days. The cells showed enhanced proliferation rates and improved osteoblast function through mineral formation on the positively and negatively charged LN surfaces compared to electrostatically neutral x-cut LN and a glass cover slip control. These results highlight the potential of LN as a template for investigating the role of charge on cellular processes.
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14.
  • Cecchinato, Francesca, et al. (författare)
  • In vitro evaluation of human fetal osteoblast response to magnesium loaded mesoporous TiO2 coating.
  • 2014
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 102:11, s. 3862-3871
  • Tidskriftsartikel (refereegranskat)abstract
    • This work aimed to evaluate the in vitro response of Transfected Human Foetal Osteoblast (hFOB) cultured on a magnesium-loaded mesoporous TiO2 coating. The application of mesoporous films on titanium implant surfaces has shown very promising potential to enhance osseointegration. This type of coating has the ability to act as a framework to sustain bioactive agents and different drugs. Magnesium is the element that, after calcium, is the most frequently used to dope titanium implant surfaces, since it is crucial for protein formation, growth factor expression, and aids for bone mineral deposition on implant surfaces. Mesoporous TiO2 films with an average pore-size of 6 nm were produced by the evaporation-induced self-assembly method (EISA) and deposited onto titanium discs. Magnesium loading was performed by soaking the mesoporous TiO2 discs in a magnesium chloride solution. Surface characterization was conducted by SEM, XPS, optical interferometry, and AFM. Magnesium release profile was assessed at different time points using a Magnesium Detection kit. Cell morphology and spreading were observed with SEM. The cytoskeletal organization was stained with TRITC-conjugated Phalloidin and cell viability was evaluated through a mitochondrial colorimetric (MTT) assay. Furthermore, gene expression of bone markers and cell mineralization were analyzed by real time RT-PCR and alizarin-red staining, respectively. The surface chemical analysis by XPS revealed the successful adsorption of magnesium to the mesoporous coating. The AFM measurements revealed the presence of a nanostructured surface roughness. Osteoblasts viability and adhesion as well as the gene expression were unaffected by the addition of magnesium possibly due to its rapid burst release, however, were enhanced by the 3D nanostructure of the TiO2 layer.
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15.
  • Chai, Wen L, et al. (författare)
  • Ultrastructural analysis of implant-soft tissue interface on a three dimensional tissue-engineered oral mucosal model.
  • 2012
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 100A:2, s. 269-277
  • Tidskriftsartikel (refereegranskat)abstract
    • A three dimensional tissue-engineered human oral mucosal model (3D OMM) used in the investigation of implant-soft tissue interface was recently reported. The aim of this study was to examine the ultrastructural features of soft tissue attachment to various titanium (Ti) implant surfaces based on the 3D OMM. Two techniques, that is, focus ion beam (FIB) and electropolishing techniques were used to prepare specimens for transmission electron microscopic (TEM) analysis of the interface. The 3D OM consisting of both epithelial and connective tissue layers was constructed by co-culturing human oral keratinocytes and fibroblasts onto an acellular dermis scaffold. Four types of Ti surface topographies were tested: polished, machined (turned), sandblasted, and TiUnite. The specimens were then processed for TEM examination using FIB (Ti remained) and electropolishing (Ti removed) techniques. The FIB sections showed some artifact and lack of details of ultrastructural features. In contrast, the ultrathin sections prepared from the electropolishing technique showed a residual Ti oxide layer, which preserved the details for intact ultrastructural interface analysis. There was evidence of hemidesmosome-like structures at the interface on the four types of Ti surfaces, which suggests that the tissue-engineered oral mucosa formed epithelial attachments on the Ti surfaces. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
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16.
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17.
  • Esguerra, Maricris, 1981, et al. (författare)
  • Intravital fluorescent microscopic evaluation of bacterial cellulose as scaffold for vascular grafts.
  • 2010
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 93:1, s. 140-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Although commonly used synthetic vascular grafts perform satisfactorily in large caliber blood vessels, they are prone to thrombosis in small diameter vessels. Therefore, small vessels might benefit from tissue engineered vascular grafts. This study evaluated bacterial cellulose (BC) as a potential biomaterial for biosynthetic blood vessels. We implanted the dorsal skinfold chambers in three groups of Syrian golden hamsters with BC (experimental group), polyglycolic acid, or expanded polytetrafluorethylene (control groups). Following implantation, we used intravital fluorescence microscopy, histology, and immunohistochemistry to analyze the biocompatibility, neovascularization, and incorporation of each material over a time period of 2 weeks. Biocompatibility was good in all groups, as indicated by the absence of leukocyte activation upon implantation. All groups displayed angiogenic response in the host tissue, but that response was highest in the polyglycolic acid group. Histology revealed vascularized granulation tissue surrounding all three biomaterials, with many proliferating cells and a lack of apoptotic cell death 2 weeks after implantation. In conclusion, BC offers good biocompatibility and material incorporation compared with commonly used materials in vascular surgery. Thus, BC represents a promising new biomaterial for tissue engineering of vascular grafts.
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18.
  • Faxälv, Lars, et al. (författare)
  • Imaging of blood plasma coagulation and its propagation at surfaces.
  • 2008
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 85:4, s. 1129-34
  • Tidskriftsartikel (refereegranskat)abstract
    • A new method utilizing image capture and processing was developed for the analysis of blood plasma coagulation at surfaces. The coagulation was detected in a cuvette by time-lapse image capture of light scattering from the developing fibrin network. By image processing and computer analysis of the captured image data, both early detection of coagulation at the surface and the propagation phase of coagulation could be measured in the same experiment. It is possible to use both platelet-rich plasma (PRP) and platelet-free plasma (PFP) with the method, and thereby study the platelet contribution to both surface coagulation and propagation of coagulation. Two well-known model surfaces, hydrophilic and hydrophobic glass, were used in combination with PRP and PFP to illustrate the method. Hydrophilic glass activated coagulation significantly faster (PRP: 7.0 +/- 1.7 min, PFP: 5.9 +/- 1.2 min, n= 16) than hydrophobic glass (PRP: 50 +/- 14 min, PFP: 65 +/- 32 min, n = 16) in both PRP and PFP. Hydrophilic surfaces showed a faster initial propagation of coagulation adjacent to the surface (mean velocity: 0.14 +/- 0.05 mm/ minute) compared with the propagation observed further out from the surface (mean velocity: 0.05 +/- 0.01 mm/min). The method is very flexible and can be suitable for screening hemocompatibility of biomaterials.
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19.
  • Ferraz, Natalia, et al. (författare)
  • In vitro and in vivo toxicity of rinsed and aged nanocellulose-polypyrrole composites
  • 2012
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 100A:8, s. 2128-2138
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel composites of nanocellulose and the conducting polymer polypyrrole (PPy) are herein suggested as potential candidates for active ion-extraction membranes in electrochemically controlled hemodialysis. This work has defined processing parameters to obtain a biocompatible nanocellulose-PPy composite and for the first time, the effect of the composite ageing on cell viability has been studied.The influence of rinsing and extraction process steps, as well as ageing under different conditions (i.e. in air, at –20 ˚C and in argon), on the electroactivity and cytotoxicity of a PPy-nanocellulose composite has been investigated. The biocompatibility evaluation was based on indirect toxicity assays with fibroblasts and monocyte cell lines and an acute toxicity test in mice, while the electroactivity was evaluated by cyclic voltammetry experiments.The as-prepared composite did not induce any cytotoxic response in vitro or in vivo. Extensive rinsing and 48 hour incubation in biological buffer previous to the preparation of the culture medium extracts were, however, necessary to obtain a non-cytotoxic composite. The as-prepared composite was also found to exhibit acceptable electrochemical performance, which was retained upon 4 weeks storage in argon atmosphere.  It was shown that ageing of the composite had a negative effect on biocompatibility, regardless of the storage condition. Thus, to allow for long time storage of electroactive nanocellulose-PPy hemodialysis membranes, the degradation of PPy upon storage must be controlled. The present results show that the biocompatibility of PPy composites depends on the rinsing and pre-treatment of the composite material as well as the aging of the material.
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20.
  • Ferraz, Natalia, et al. (författare)
  • Nanoporesize affects complement activation
  • 2008
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 87:3, s. 575-81
  • Tidskriftsartikel (refereegranskat)abstract
    • In the present study, we have shown the vast importance of biomaterial nanotexture when evaluating inflammatory response. For the first time in an in vitro whole blood system, we have proven that a small increase in nanoporesize, specifically 180 nm (from 20 to 200 nm), has a huge effect on the complement system. The study was done using nanoporous aluminiumoxide, a material that previously has been evaluated for potential implant use, showing good biocompatibility. This material can easily be manufactured with different pore sizes making it an excellent candidate to govern specific protein and cellular events at the tissue-material interface. We performed whole blood studies, looking at complement activation after blood contact with two pore size alumina membranes (pore diameters, 20 and 200 nm). The fluid phase was analyzed for complement soluble components, C3a and sC5b-9. In addition, surface adsorbed proteins were eluted and dot blots were performed to detect IgG, IgM, C1q, and C3. All results point to the fact that 200 nm pore size membranes are more complement activating. Significantly, higher values of complement soluble components were found after whole blood contact with 200 nm alumina and all studied proteins adsorbed more readily to this membrane than to the 20 nm pore size membrane. We hypothesize that the difference in complement activation between our two test materials is caused by the type and the amount of adsorbed proteins, as well as their conformation and orientation. The different protein patterns created on the two alumina membranes are most likely a consequence of the material topography.
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21.
  • Fink, Helen, 1978, et al. (författare)
  • An in vitro study of blood compatibility of vascular grafts made of bacterial cellulose in comparison with conventionally-used graft materials
  • 2011
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 97A:1, s. 52-58
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study we analyzed the blood compatibility of bacterial cellulose (BC) as a new biosynthetic material for use as a vascular graft. As reference materials we used expanded polytetrafluoroethylene (ePTFE) and poly(ethylene terephthalate) (PET) vascular grafts. These materials are in clinical use today. Tubes with inner diameters of both 4 (not PET) and 6 mm were tested. Heparin-coated PVC tubes (hepPVC) were used as a negative control. Platelet consumption and thrombin-antithrombin complex (TAT) were used as parameters of coagulation and for complement activation, sC3a and sC5b-9 were used. The investigated parameters were measured after 1-h exposure to freshly drawn human blood supplemented with a low dose of heparin in a Chandler loop system. The results showed that BC exhibits no significant difference in platelet consumption, as compared with PET 16 mm), ePTFE and hepPVC. The PET material consumed more platelets than any of the other materials. The TAT generation for 4 mm tubes was not significantly different between BC and the other materials. For 6 mm tubes, however, differences were observed between hepPVC and PET (p < 0.0001); BC and hepPVC (p = 0.0016); ePTFE and PET (p < 0.0001); BC and ePTFE (p = 0.0029); BC and PET (p = 0.0141). Surprisingly, considering the low platelet consumption, the complement activation parameters (sC3a and sC5b-9) were much higher for BC, as compared with the other materials for both 4 and 6 mm tubes.
  •  
22.
  • Ghane, Nazanin, et al. (författare)
  • Regeneration of the peripheral nerve via multifunctional electrospun scaffolds
  • 2021
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 109:4, s. 437-452
  • Forskningsöversikt (refereegranskat)abstract
    • Over the last two decades, electrospun scaffolds have proved to be advantageous in the field of nerve tissue regeneration by connecting the cavity among the proximal and distal nerve stumps growth cones and leading to functional recovery after injury. Multifunctional nanofibrous structure of these scaffolds provides enormous potential by combining the advantages of nano‐scale topography, and biological science. In these structures, selecting the appropriate materials, designing an optimized structure, modifying the surface to enhance biological functions and neurotrophic factors loading, and native cell‐like stem cells should be considered as the essential factors. In this systematic review paper, the fabrication methods for the preparation of aligned nanofibrous scaffolds in yarn or conduit architecture are reviewed. Subsequently, the utilized polymeric materials, including natural, synthetic and blend are presented. Finally, their surface modification techniques, as well as, the recent advances and outcomes of the scaffolds, both in vitro and in vivo, are reviewed and discussed.
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23.
  • Göransson, Anna, 1970, et al. (författare)
  • An in vitro comparison of possibly bioactive titanium implant surfaces.
  • 2009
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:4, s. 1037-1047
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. Fluoride etched (Fluoride), 2. Alkali-heat treated (AH), 3. Magnesium ion incorporated anodized (TiMgO), and 4. Nano HA coated and heat treated (nano HA) in vitro. Furthermore, to evaluate the significance of the SBF formed CaP coat on bone cell response. The surfaces were characterized by Optical Interferometry, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). CaP formation was evaluated after 12, 24 and 72 h in simulated body fluid (SBF). Primary human mandibular osteoblast-like cells were cultured on the various surfaces subjected to SBF for 72 h. Cellular attachment, differentiation (osteocalcin) and protein production (TGF-beta(1)) was evaluated after 3 h and 10 days respectively. Despite different morphological appearances, the roughness of the differently modified surfaces was similar. The possibly bioactive surfaces gave rise to an earlier CaP formation than the blasted surface, however, after 72 h the blasted surface demonstrated increased CaP formation compared to the possibly bioactive surfaces. Subsequent bone cell attachment was correlated to neither surface roughness nor the amount of formed CaP after SBF treatment. In contrast, osteocalcin and TGF-beta(1) production were largely correlated to the amount of CaP formed on the surfaces. However, bone response (cell attachment, osteocalcin and TGF-F production) on the blasted controls were similar or increased compared to the SBF treated fluoridated, AH and TiMgO surface. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.
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24.
  • Göransson, Anna, 1970, et al. (författare)
  • Inflammatory response to titanium surfaces with fibrinogen and catalase coatings: an in vitro study.
  • 2007
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 80:3, s. 693-9
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turned titanium "Fib") and antiinflammatory proteins (catalase on top of fibrinogen coated turned titanium "Cat"). Additionally, turned titanium surfaces (Ti) were used as controls. The discs were incubated with human mononuclear cells. Adhered cells were investigated with respect to number, viability, differentiation (acute marker 27E10 vs. chronic marker RM3/1), and cytokine production (TNF-alpha and IL-10), after 24 and 72 h. The results indicated that it is possible to modulate the inflammatory response with protein coatings. However, the strongest inflammatory response, indicated by increased number of adhered cells and release of pro and antiinflammatory mediators, was induced by Cat. Furthermore, the cytokine production on this surface was not sensitive to LPS stimulation. Differentiation measured as the expression of the chronic cell surface marker, dominated after 72 h for all surface modifications and Cat displayed an increased number compared to the others. A decrease in the total number of adhered cells and amounts of TNF-alpha were observed on all surfaces over time. The cell viability was, in general, high for all tested surfaces. In conclusion, the study proved it possible to influence the early inflammatory response in vitro by immobilizing protein coatings to titanium surfaces. However, the catalase surface demonstrated the strongest inflammatory response, and the possibility to selectively use the potent antiinflammatory capacity of catalase needs to be further evaluated.
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25.
  • Han, Yilin, et al. (författare)
  • Effect of scaffold properties on adhesion and maintenance of boundary cap neural crest stem cells in vitro
  • 2020
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 108:6, s. 1274-1280
  • Tidskriftsartikel (refereegranskat)abstract
    • Optimal combination of stem cells and biocompatible support material is a promising strategy for successful tissue engineering. The required differentiation of stem cells is crucial for functionality of engineered tissues and can be regulated by chemical and physical cues. Here we examined how boundary cap neural crest stem cells (bNCSCs) are affected when cultured in the same medium, but on collagen- or laminin-polyacrylamide (PAA) scaffolds of different stiffness (0.5, 1, or similar to 7 kPa). bNCSCs displayed marked differences in their ability to attach, maintain a large cell population and differentiate, depending on scaffold stiffness. These findings show that the design of physical cues is an important parameter to achieve optimal stem cell properties for tissue repair and engineering.
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26.
  • Helenius, Gisela, 1973, et al. (författare)
  • In vivo biocompatibility of bacterial cellulose
  • 2006
  • Ingår i: Journal of biomedical materials research. - : Wiley. - 1549-3296 .- 1552-4965. ; 76:2, s. 431-8
  • Tidskriftsartikel (refereegranskat)abstract
    • The biocompatibility of a scaffold for tissue engineered constructs is essential for the outcome. Bacterial cellulose (BC) consists of completely pure cellulose nanofibrils synthesized by Acetobacter xylinum. BC has high mechanical strength and can be shaped into three-dimensional structures. Cellulose-based materials induce negligible foreign body and inflammatory responses and are considered as biocompatible. The in vivo biocompatibility of BC has never been evaluated systematically. Thus, in the development of tissue engineered constructs with a BC scaffold, it is necessary to evaluate the in vivo biocompatibility. BC was implanted subcutaneously in rats for 1, 4, and 12 weeks. The implants were evaluated in aspects of chronic inflammation, foreign body responses, cell ingrowth, and angiogenesis, using histology, immunohistochemistry, and electron microscopy. There were no macroscopic signs of inflammation around the implants. There were no microscopic signs of inflammation either (i.e., a high number of small cells around the implants or the blood vessels). No fibrotic capsule or giant cells were present. Fibroblasts infiltrated BC, which was well integrated into the host tissue, and did not elicit any chronic inflammatory reactions. The biocompatibility of BC is good and the material has potential to be used as a scaffold in tissue engineering.
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27.
  • Hoess, Andreas, et al. (författare)
  • Self-supporting nanoporous alumina membranes as substrates for hepatic cell cultures
  • 2012
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 100A:9, s. 2230-2238
  • Tidskriftsartikel (refereegranskat)abstract
    • Membranes made from nanoporous alumina exhibit interesting properties for their use in biomedical research. They show high porosity and the pore diameters can be easily adjusted in a reproducible manner. Nanoporous alumina membranes are thus ideal substrates for the cultivation of polar cells (e.g., hepatocytes) or the establishment of indirect co-cultures. The porous nature of the material allows supply of nutrients to both sides of adherent cells and the exchange of molecules across the membrane. However, it is well-known that surface features in the nanometer range affect cellular behavior. In this study, the response of HepG2 cells to nanoporous alumina membranes with three different pore diameters, ranging from 50 to 250 nm, has been evaluated. The cellular interactions with the nanoporous materials were assessed by investigating cell adhesion, morphology, and proliferation. Cell functionality was measured by means of albumin production. The membranes supported good cell adhesion and spreading. Compared to tissue culture plastic, the cells on the porous substrates developed distinct focal adhesion sites and actin stress fibers. Additionally, electron microscopical investigations revealed the penetration of cellular extensions into pores with diameters bigger than 200 nm. Furthermore, cell proliferation significantly increased with an increase in pore diameter, whereas the albumin production followed a reverse trend. Thus, it seems to be possible to direct cellular behavior of HepG2 cells growing on nanoporous alumina by changing the pore diameter of the material. Hence, nanoporous alumina membranes can be useful culture substrates to develop new approaches in the field of liver tissue engineering.
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28.
  • Hulsart-Billström, Gry, et al. (författare)
  • Osteogenic potential of Sr-doped calcium phosphate hollow spheres in vitro and in vivo
  • 2013
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 101:8, s. 2322-2331
  • Tidskriftsartikel (refereegranskat)abstract
    • Treatment of osteoporotic fractures with conventional surgical methods is associated with a high rate of complications. Intense search for new treatment options includes development of specific biomaterials aimed to be part of the surgical armamentarium. Strontium doped calcium phosphate spheres (SrCPS) is a new material that might be of interest due to the influence on osteoclast and osteoblast activity. In the present study, we successfully constructed hollow spherical SrCPS particles with a diameter of ∼700 nm and shell thickness of ∼150 nm. The Sr content was about 20 wt %. Cell viability and cytotoxicity were investigated in vitro with concentrations from 0 to 1000 μg/mL of SrCPS in medium extract in a day chase study. The in vivo biocompatibility was tested in a delayed bone-healing model in a rat vertebral defect by histology, μCT, and nanoSPECT. The SrCPS showed no toxicity in vitro with comparable cell number in all concentrations. Increased metabolism was seen in the cell viability study in cells exposed to 400 and 600 μg/mL. SPECT showed good biocompatibility with no local adverse effects and an increased osteoblast activity as compared to adjacent vertebra. SrCPS implantation induced bone formation and resulted in complete resorption and defect consolidation.
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29.
  • Ichioka, Yuki, et al. (författare)
  • Epigenetic changes of osteoblasts in response to titanium surface characteristics.
  • 2021
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 109:2, s. 170-180
  • Tidskriftsartikel (refereegranskat)abstract
    • We aimed to investigate the influence of titanium surface characteristics on epigenetic mechanisms and DNA damage/repair pathways. Osteoblast-like cells (MG63) were incubated on glass, smooth titanium, and minimally rough titanium discs, respectively, for 0, 1, 6, and 24hr. The presence of double-stranded DNA damage (γH2AX), DNA repair (Chk2), and epigenetic markers (AcH3 & DNMT1) were investigated using immunofluorescence. There were no Chk2-positive cells on the minimally rough titanium surfaces at all-time points, in comparison to glass and smooth titanium. Total γH2AX-positive cells on minimally rough titanium gradually decreased as incubation time increased, on the contrary to smooth titanium. Minimally rough titanium surfaces induced cytoplasmic staining of DNMT1 up to 99% at 24hr. For epigenetic markers related to the DNA damage/repair pathway, minimally rough titanium surfaces showed the lower percentage of AcH3-positive cells compared to glass and smooth titanium surface. The findings in the current study show that titanium surface characteristics indeed influence DNA damage and the DNA repair pathway, including epigenetic factors.
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30.
  • Idris, Shaza Bushra, et al. (författare)
  • Polyester copolymer scaffolds enhance expression of bone markers in osteoblast-like cells
  • 2010
  • Ingår i: J BIOMED MATER RES PART A. - : Wiley. - 1549-3296. ; 94A:2, s. 631-639
  • Tidskriftsartikel (refereegranskat)abstract
    • In tissue engineering, the resorbable aliphatic polyester poly(L-lactide) (PLLA) is used as scaffolds in bone regeneration. Copolymers of poly(L-lactide)-co-(epsilon-caprolactone) [poly(LLA-co-CL)] and poly(L-lactide)-co-(1,5-dioxepan-2-one) [poly(LLA-co-DXO)], with superior mechanical properties to PLLA, have been developed to be used as scaffolds, but the influence on the osteogenic potential is unclear. This in vitro study of test scaffolds of poly(LLA-co-CL) and poly(LLA-co-DXO) using PLLA scaffolds as a control demonstrates the attachment and proliferation of human osteoblast-like cells (HOB) as measured by SEM and a methylthiazol tetrazolium (MTT) colorimetric assay, and the progression of HOB osteogenesis for up to 3 weeks; expressed as synthesis of the osteoblast differentiation markers: collagen type 1 (Col 1), alkaline phosphatase, bone sialoprotein, osteocalcin (OC), osteopontin and runt related gene 2 (Runx2). Surface analysis disclosed excellent surface attachment, spread and penetration of the cells into the pores of the test scaffolds compared to the PLLA. MTT results indicated that test scaffolds enhanced the proliferation of HOBs. Cells grown on the test scaffolds demonstrated higher synthesis of Col 1 and OC and also increased bone markers mRNA expression. Compared to scaffolds of PLLA, the poly(LLA-co-CL) and poly(LLA-co-DXO) scaffolds enhanced attachment, proliferation, and expression of osteogenic markers by HOBs in vitro. Therefore, these scaffolds might be appropriate carriers for bone engineering. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 631-639, 2010
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31.
  • Ivanov, Alexander, et al. (författare)
  • Boronate-containing polymer brushes: Characterization, interaction with saccharides and mammalian cancer cells.
  • 2009
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:1, s. 213-225
  • Tidskriftsartikel (refereegranskat)abstract
    • Boronate-containing polymer brushes were synthesized by free radical copolymerization of N,N-dimethylacrylamide (DMAA) and N-acryloyl-m-phenylboronic acid (NAAPBA) (9:1) on the surface of 3-mercaptopropyl-silylated glass plates and capillaries. The brushes were characterized with time-of-flight secondary ion mass-spectrometry (ToF SIMS), atomic force microscopy and contact angle measurements. Fructose caused a well-expressed drop spreading on the surface of copolymer-grafted glass, due to the strong interaction with the boronate groups. Sedimentation of murine hybridoma cells M2139 or human myeloid leukemia cells KG1 onto the DMAA-NAAPBA copolymer-grafted glass plates from 10 mM phosphate buffer solution (pH 8.0) resulted in the cell adhesion. The adhered M2139 and KG1 cells could be quantitatively detached from the grafted plates with 0.1M fructose, which competed with cell surface carbohydrates for binding to the boronates. Evaluation of the binding strength between M2139 cells and the copolymer brush was performed by exposure of the adhered cells to a shear stress. Detachment of a fraction of 18% of the adhered M2139 cells was obtained at a shear force of 1400-2800 pN/cell generated by the running phosphate buffer (pH 8.0), whereas the remaining adhered cells (70%) could be detached with 0.1M fructose dissolved in the same buffer. Possible applications of the boronate-containing polymer brushes to affinity cell separation can be based upon the facile recovery of the attached cells. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008.
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32.
  • Jarmar, T., et al. (författare)
  • Technique for preparation and characterization in cross-section of oral titanium implant surfaces using focused ion beam and transmission electron microscopy
  • 2008
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 87:4, s. 1003-9
  • Tidskriftsartikel (refereegranskat)abstract
    • The surface properties of materials are believed to control most of the biological reactions toward implanted materials. To study the surface structure, elemental distribution, and morphology, using transmission electron microscopy (TEM) techniques, thin foils of the surface (in cross-section) are needed. These have been cumbersome to produce, in particular, from the normally irregular screw-shaped metal implants. Focused ion beam (FIB) microscopy has been developed partly for TEM sample preparation, mainly within the microelectronics industry. Our study describes a method based on FIB for producing electron transparent foils/sections from a metal implant for TEM analysis. Using a screw-shaped titanium dental implant, it was demonstrated that thin foils can be prepared with submicron specificity and from almost any surface geometry. A comparison of different lift-out techniques showed that the in situ lift-out preparation technique allowed plasma cleaning and produced particularly good samples with excellent yield. The titanium oxide on the implant surface was analyzed using energy-filtered TEM (EFTEM) and high-resolution TEM (HRTEM) and the TiO(2) rutile phase being determined via the lattice parameters. This study provides the first set of data for the optimization of a new route for preparation and analysis of biomaterial surfaces and interfaces.
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33.
  • Jedenmalm, Anneli, et al. (författare)
  • Effect of head surface roughness and sterilization on wear of UHMWPE acetabular cups
  • 2009
  • Ingår i: Journal of Biomedical Materials Research. - : Wiley. - 0021-9304 .- 1097-4636 .- 1549-3296 .- 1552-4965. ; 90:4, s. 1032-1042
  • Tidskriftsartikel (refereegranskat)abstract
    • The impact of femoral head surface roughness on wear of gamma-irradiation sterilized (3 MRad in nitrogen, crosslinked) and nonsterilized (not crosshnked) UHMWPE acetabular cups has been evaluated. Gravimetric wear testing was performed in a hip joint simulator for 2 x 10(6) cycles. CoCrMo heads were used with different surface roughness (R-a = 15 nm and R-a = 400 rim). The surface roughness after wear test was unchanged for the roughened heads, whereas the initially smooth heads showed a few scratches. The roughened heads increased the wear of the acetabular cups 2-fold. The gamma-irradiated cups tested against rough heads underwent the highest wear. The absorption of water was highest for the gamma-irradiated cups (0.0204% compared to 0.0031% after 85 days). Raman spectroscopy showed small but significant crystallinity changes in the wear zone, where the gamma-irradiated cups with the most extensive abrasion increased in crystallinity, whereas the nonsterilized cups underwent a crystallinity decrease.
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34.
  • Johansson, Pär, et al. (författare)
  • Biomechanical, histological, and computed X-ray tomographic analyses of hydroxyapatite coated PEEK implants in an extended healing model in rabbit
  • 2018
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 106:5, s. 1440-1447
  • Tidskriftsartikel (refereegranskat)abstract
    • A nanosized hydroxyapatite (HA) modification on polyetheretherketone (PEEK) using a novel spin coating technique was investigated in a rabbit model. Spin coating technique creates a 20-40 nm thick layer of nanosized HA particles with similar shape, size, and crystallinity as human bone. Some implants were designed with a perforating hole in the apical region to mimic a fusion chamber of a spinal implant. The coating nano-structures were assessed using a scanning electron microscope. The in vivo response to HA-PEEK was compared to untreated PEEK with respect to removal torque, histomorphometry, and computed microtomography. The HA-coated and pure PEEK implants were inserted in the tibia and femur bone according to simple randomization. The rabbits were sacrificed 20 weeks after implantation. Removal torque analysis showed significantly higher values for HA-PEEK. Qualitative histological evaluation revealed an intimate contact between PEEK and the bone at the threads and perforated hole. Histomorphometric assessment showed higher bone-implant and bone area values for HA-PEEK but without statistical significance. The effect of the HA coating showed most prominent effect in the removal torque which may be correlated to an alteration in the bone quality around the HA-PEEK implants. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1440-1447, 2018.
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35.
  • Karlsson, Johan, 1984, et al. (författare)
  • Stem cell homing using local delivery of plerixafor and stromal derived growth factor-1alpha for improved bone regeneration around Ti-implants
  • 2016
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 104:10, s. 2466-2475
  • Tidskriftsartikel (refereegranskat)abstract
    • Triggering of the early healing events, including the recruitment of progenitor cells, has been suggested to promote bone regeneration. In implantology, local drug release technologies could provide an attractive approach to promote tissue regeneration. In this study, we targeted the chemotactic SDF-1a/CXCR4 axis that is responsible e.g. for the homing of stem cells to trauma sites. This was achieved by local delivery of plerixafor, an antagonist to CXCR4, and/or SDF-1a from titanium implants coated with mesoporous titania thin films with a pore size of 7.5 nm. In vitro drug delivery experiments demonstrated that the mesoporous coating provided a high drug loading capacity and controlled release. The subsequent in vivo study in rat tibia showed beneficial effects with respect to bone-implant anchorage and bone-formation along the surface of the implants when plerixafor and SDF-1a were delivered locally. The effect was most prominent by the finding that the combination of the drugs significantly improved the mechanical bone anchorage. These observations suggest that titanium implants with local delivery of drugs for enhanced local recruitment of progenitor cells have the ability to promote osseointegration. This approach may provide a potential strategy for the development of novel implant treatments.
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36.
  • Karlsson, Johan, 1984, et al. (författare)
  • The effect of alendronate on biomineralization at the bone/implant interface
  • 2016
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 104:3, s. 620-629
  • Tidskriftsartikel (refereegranskat)abstract
    • A recent approach to improve the osseointegration of implants is to utilize local drug administration. The presence of an osteoporosis drug may influence both bone quantity and quality at the bone/implant interface. Despite this, the performance of bone-anchoring implants is traditionally evaluated only by quantitative measurements. In the present study, the osteoporosis drug alendronate (ALN) was administrated from mesoporous titania thin films that were coated onto titanium implants. The effect that the drug had on biomineralization was explored both in vitro using simulated body fluid (SBF) and in vivo in a rat tibia model. The SBF study showed that the apatite formation was completely hindered at a high concentration of ALN (0.1 mg/mL). However, when ALN was administrated from the mesoporous coating the surface became completely covered with apatite. Ex vivo characterization of the bone/implant interface using Raman spectroscopy demonstrated that the presence of ALN enhanced the bone mineralization, and that the chemical signature of newly formed bone in the presence of ALN had a higher resemblance to the pre-existing mature bone than to the bone formed without drug. Taken together, this study demonstrates the importance of evaluating the quality of the formed bone to better understand the performance of implants.
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37.
  • Karlsson, Johan, et al. (författare)
  • The effect of alendronate on biomineralization at the bone/implant interface.
  • 2016
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 104:3, s. 620-629
  • Tidskriftsartikel (refereegranskat)abstract
    • A recent approach to improve the osseointegration of implants is to utilize local drug administration. The presence of an osteoporosis drug may influence both bone quantity and quality at the bone/implant interface. Despite this, the performance of bone-anchoring implants is traditionally evaluated only by quantitative measurements. In the present study, the osteoporosis drug alendronate (ALN) was administrated from mesoporous titania thin films that were coated onto titanium implants. The effect that the drug had on biomineralization was explored both in vitro using simulated body fluid (SBF) and in vivo in a rat tibia model. The SBF study showed that the apatite formation was completely hindered at a high concentration of ALN (0.1 mg/mL). However, when ALN was administrated from the mesoporous coating the surface became completely covered with apatite. Ex vivo characterization of the bone/implant interface using Raman spectroscopy demonstrated that the presence of ALN enhanced the bone mineralization, and that the chemical signature of newly formed bone in the presence of ALN had a higher resemblance to the pre-existing mature bone than to the bone formed without drug. Taken together, this study demonstrates the importance of evaluating the quality of the formed bone to better understand the performance of implants. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A 104A: 620-629, 2016.
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38.
  • Laschke, MW, et al. (författare)
  • New experimental approach to study host tissue response to surgical mesh materials in vivo
  • 2005
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 74A:4, s. 696-704
  • Tidskriftsartikel (refereegranskat)abstract
    • Implantation of surgical meshes is a common procedure to increase abdominal wall stability in hernia repair. To improve biocompatibility of the implants, sophisticated in vivo animal models are needed to study inflammation and incorporation of biomaterials. Herein, we have established a new model that allows for the quantitative analysis of host tissue response and vascular ingrowth into surgical mesh materials in vivo. Ultrapro meshes were implanted into dorsal skinfold chambers of Syrian golden hamsters. Angiogenesis, microhemodynamics, microvascular permeability, and leukocyte-endothelial cell interaction of the host tissue were analyzed in response to material implantation over a 2-week period using intravital fluorescence microscopy. Mesh implantation resulted in a short-term activation of leukocytes, reflected by leukocyte accumulation and adherence in postcapillary venules. This cellular inflammatory response was accompanied by an increase of mac-romolecular leakage, indicating loss of integrity of venular endothelial cells. Angiogenesis started at day 3 after implantation by protrusion of capillary sprouts, originating from the host microvasculature. Until day 10, these sprouts interconnected with each other to form a new microvascular network. At day 14, the inflammatory response had disappeared and the vascular ingrowth was completed. Histology confirmed the formation of granulation tissue with adequate incorporation of the mesh filaments within the host tissue. We conclude that this novel model of surgical mesh implantation is a useful experimental approach to analyze host tissue response and vascular ingrowth of newly devised materials for hernia repair.
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39.
  • Linderbäck, Paula, et al. (författare)
  • Sol-gel derived titania coating with immobilized bisphosphonate enhances screw fixation in rat tibia.
  • 2010
  • Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 94:2, s. 389-95
  • Tidskriftsartikel (refereegranskat)abstract
    • A variety of surface modifications have been tested for the enhancement of screw fixation in bone, and locally delivered anti-osteoporosis drugs such as bisphosphonates (BP) are then of interest. In this in vivo study, the impact of surface immobilized BP was compared with systemic BP delivery and screws with no BP. After due in vitro characterization, differently treated stainless steel (SS) screws were divided into four groups with 10 rats each. Three of the groups received screws coated with sol-gel derived TiO(2) and calcium phosphate (SS+TiO(2)+CaP). One of these had no further treatment, one had alendronate (BP) adsorbed to calcium phosphate mineral, and one received systemic BP treatment. The fourth group received uncoated SS screws and no BP (control). The screw pullout force was measured after 4 weeks of implantation in rat tibiae. The immobilized amount and release rate of alendronate could be controlled by different immersion times. The SS+TiO(2)+CaP coating did not increase the pullout force compared to SS alone. Surface delivered alendronate enhanced the pullout force by 93% [p = 0.000; 95% Confidence Interval (CI): 67-118%] compared to SS, and by 39% (p = 0.044; 95% CI: 7-71%) compared to systemic alendronate delivery. Both surface immobilized and systemically delivered alendronate improved implant fixation. Also, locally delivered, that is, surface immobilized alendronate showed a better fixation than systemically delivered. Using sol-gel derived TiO(2) as a platform, it is possible to administer controllable amounts of a variety of BPs.
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40.
  • Lindholm-Sethson, Britta, et al. (författare)
  • Effects of pH and fluoride concentration on the corrosion of titanium
  • 2008
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 86A:1, s. 149-159
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this investigation was to confirm and summarize the corrosion behavior of titanium in saline solution at different pH and fluoride concentration, and to characterize the surface films and the stability of a passive and aged titanium surface using open circuit potential measurements, electrochemical impedance spectroscopy, and anodic polarization curves. The results from the electrochemical measurements were related to titanium released after 2-min brushing with saline solutions with different pH and fluoride concentration, that is, simulating tooth brushing with fluoride containing prophylactic substances. Titanium was analyzed using atomic adsorption spectrophotometry. The pH in the saline solution was varied between 4 and 7 with additions of sodium fluoride up to 1.0 wt %. The presence of fluoride in solution was unfavorable for the stability of titanium and led to corrosion and the release of titanium especially at low pH. The combination of low pH and presence of fluoride ions in solution destroyed a passive film on the titanium surface even after aging for 170 h in neutral saline solution. The results do not necessarily imply the occurrence of biological soft tissue related effects even if a physical contact between titanium and the surrounding milieu is prevalent. To provide a general understanding of electrochemical techniques in biomaterial research, much effort was put in the qualitative description of the results, with the intention to provide a broader understanding of especially the impedance method to other researchers. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007.
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41.
  •  
42.
  • Magnusson, Catarina, et al. (författare)
  • Inhibitory effects of orthosilicic acid on osteoclastogenesis in RANKL-stimulated RAW264.7 cells
  • 2021
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 109:10, s. 1967-1978
  • Tidskriftsartikel (refereegranskat)abstract
    • Numerous studies have reported on the positive effects of silicon (Si) on bone metabolism, particularly on the stimulatory effects of Si on osteoblast cells and on bone formation. Inhibitory effects of Si on osteoclast formation and bone resorption have also been demonstrated in vitro and are suggested to be mediated indirectly via stromal and osteoblast cells. Direct effects of Si on osteoclasts have been less studied and mostly using soluble Si, but no characterisation of the Si treatment solutions are provided. The aims of the present study were to (a) further investigate the direct inhibitory effects of Si on osteoclastogenesis in RANKL-stimulated RAW264.7 cells, (b) determine at what stage during osteoclastogenesis Si acts upon, and (c) determine if these effects can be attributed to the biologically relevant soluble orthosilicic acid specie. Our results demonstrate that silicon, at 50 mu g/ml (or 1.8 mM), does not affect cell viability but directly inhibits the formation of TRAP+ multinucleated cells and the expression of osteoclast phenotypic genes in RAW264.7 cells. The inhibitory effect of Si was clearly associated with the early stages (first 24 hr) of osteoclastogenesis. Moreover, these effects can be attributed to the soluble orthosilicic acid specie.
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43.
  • Malekzadeh, Benoosh, et al. (författare)
  • Effects of locally administered insulin on bone formation in non-diabetic rats
  • 2013
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:1, s. 132-137
  • Tidskriftsartikel (refereegranskat)abstract
    • The possibility to control bone formation would be favorable in many areas of medicine, where bone defects is still a major challenge. Insulin has been suggested to exert both systemic and local anabolic effects in bone tissues. This raised the question whether locally administrated insulin could provide new therapeutic strategies for patients with local bone defects and impaired bone healing. The aim of this study was to evaluate bone formation in non-diabetic rats when local insulin is administered. This study differs from previous reports in two aspects: the use of non-diabetic animals and locally administered insulin. Twenty-four implants were inserted into 12 rats-one insulin-coated and one control-in each tibia for four weeks. Interferometry and histomorphometry were used to evaluate the surface topography and bone formation, respectively. Results demonstrated no significant changes in surface topography after insulin immobilization. Histomorphometry revealed significantly more bone around the insulin-coated implants (BA) (p = 0.005) and a similar amount of bone at the implant surface (BIC) (p = 0.117) compared with the controls. It was concluded that locally administered insulin from a titanium implant surface has the potential to increase bone formation not only in diabetic subjects but also in non-diabetic subjects.
  •  
44.
  • Martinez Avila, Hector, 1985, et al. (författare)
  • Mechanical stimulation of fibroblasts in micro-channeled bacterial cellulose scaffolds enhances production of oriented collagen fibers
  • 2012
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 100A:4, s. 948-957
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose perforated by micro-channels (phi? similar to 500 mu m) has been investigated as a potential future scaffold material for meniscus implants. Scaffolds seeded with 3T6 fibroblasts were cultivated with mechanical stimulation in a compression bioreactor for enhanced collagen production. Constructs under dynamic compression at a frequency of 0.1 Hz and compression strain of 5% were compared to static cultures used as controls. The three-dimensional distributions of collagen fibers and fibroblasts in the cellulose scaffolds were studied under native, soft-matter conditions by combined second harmonic generation and coherent antiStokes Raman scattering microscopy, requiring no artificial sample preparation. Results showed that the micro-channels facilitated the alignment of cells and collagen fibers and that collagen production was enhanced by mechanical stimulation. Thus, cell-seeded, micro-channeled cellulose scaffolds provided guided tissue growth required to obtain an ultrastructure mimicking that of the meniscus.
  •  
45.
  • McGillicuddy, F. C., et al. (författare)
  • Novel "plum pudding" as potential drug-eluting stent coatings : Controlled release of fluvastatin
  • 2006
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 79A:4, s. 923-933
  • Tidskriftsartikel (refereegranskat)abstract
    • This study evaluated novel structural motifs known as "plum pudding" gels as potential drug-eluting stent coatings. Controlled delivery of a HMG-CoA reductase inhibitor (statin) from the intravascular stent surface represents a potential therapeutic modality for prevention of in-stent restenosis (ISR). In this study, gels were comprised of fluvastatin-loaded thermoresponsive microgel particles containing the relatively hydrophilic N-isopropyl-acrylamide (NiPAAm), mixed with the more hydrophobic N-tert-butylacrylamide (NtBAAm) in different wt/wt ratios: 85/15, 65/35, and 50/50, randomly dispersed in a 65/35 or 85/15 NiPAAm/NtBAAm copolymer matrix. Fluvastatin release from 5 mu m copolymer films was greatest from the most hydrophilic systems and least from the more hydrophobic systems. Release from hydrophobic matrices appeared to be via Fickian diffusion, enabling use of the Stokes-Einstein equation to determine diffusion coefficients. Release from hydrophilic matrices was nonFickian. Fluted drug retained its bioactivity, assessed as selective inhibition of human coronary artery smooth muscle cell proliferation. When stainless steel stent wires were coated (25 mu m thickness) with fluvastatin-loaded 65/35 microgels in an 85/15 copolymer matrix, drug elution into static and perfused flow environments followed similar elution profiles. In contrast to elution from copolymer films cast on flat surfaces, diffusion from stent wires coated with hydrophilic and hydrophobic systems both followed Fickian patterns, with slightly larger diffusion coefficients for elution from the flow system. We conclude that manipulation of the relative hydrophobicities of both microgel and matrix components of "plum pudding" gels results in tightly regulated release of fluvastatin over an extended time period relevant to initiation and propagation of ISR. (c) 2006 Wiley Periodicals, Inc.
  •  
46.
  • Meirelles, Luiz, 1974, et al. (författare)
  • Bone reaction to nano hydroxyapatite modified titanium implants placed in a gap-healing model
  • 2008
  • Ingår i: Journal Biomedical MAterials Research - A. - : Wiley. - 1549-3296 .- 1552-4965. ; 87:3, s. 624-631
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.
  •  
47.
  • Meirelles, Luiz, 1974, et al. (författare)
  • Nano hydroxyapatite structures influence early bone formation
  • 2008
  • Ingår i: Journal Biomedical Materials Research - A. - : Wiley. - 1549-3296 .- 1552-4965. ; 87:2, s. 299-307
  • Tidskriftsartikel (refereegranskat)abstract
    • In a study model that aims to evaluate the effect of nanotopography on bone formation, micrometer structures known to alter bone formation, should be removed. Electropolished titanium implants were prepared to obtain a surface topography in the absence of micro structures, thereafter the implants were divided in two groups. The test group was modified with nanosize hydroxyapatite particles; the other group was left uncoated and served as control for the experiment. Topographical evaluation demonstrated increased nanoroughness parameters for the nano-HA implant and higher surface porosity compared to the control implant. The detected features had increased size and diameter equivalent to the nano-HA crystals present in the solution and the relative frequency of the feature size and diameter was very similar. Furthermore, feature density per m2 showed a decrease of 13.5% on the nano-HA implant. Chemical characterization revealed calcium and phosphorous ions on the modified implants, whereas the control implants consisted of pure titanium oxide. Histological evaluation demonstrated significantly increased bone formation to the coated (p < 0.05) compared to uncoated implants after 4 weeks of healing. These findings indicate for the first time that early bone formation is dependent on the nanosize hydroxyapatite features, but we are unaware if we see an isolated effect of the chemistry or of the nanotopography or a combination of both.
  •  
48.
  • Moazzam, Parisa, et al. (författare)
  • Investigating the BSA protein adsorption and bacterial adhesion of Al-alloy surfaces after creating a hierarchical (micro/nano) superhydrophobic structure
  • 2016
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley-Blackwell. - 1549-3296 .- 1552-4965. ; 104:9, s. 2220-2233
  • Tidskriftsartikel (refereegranskat)abstract
    • Bacterial adhesion and subsequent biofilm formation on metals such as aluminum (Al) alloys lead to serious issues in biomedical and industrial fields from both an economical and health perspective. Here, we showed that a careful manipulation of Al surface characteristics via a facile two-steps superhydrophobic modification can provide not only biocompatibility and an ability to control protein adsorption and bacterial adhesion, but also address the issue of apparent long-term toxicity of Al-alloys. To find out the roles of surface characteristics, surface modification and protein adsorption on microbial adhesion and biofilm formation, the surfaces were systematically characterized by SEM, EDX, XPS, AFM, FTIR, water contact angle (WCA) goniometry, surface free energy (SFE) measurement, MTT, Bradford, Lowry and microtiter plate assays and also flow-cytometry and potentiostat analyses. Results showed that WCA and SFE changed from 70 degrees to 163 degrees and 36.3 to 0.13 mNm(-1), respectively. The stable and durable modification led to a substantial reduction in static/dynamic BSA adsorption. The effect of such a treatment on the biofilm formation was analyzed by using three different bacteria of Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. The microtiter plate assay and flow cytometry analysis showed that the modification not only could substantially reduce the bacterial adhesion but this biofouling resistance is independent of bacterium type. An excellent cell viability after exposure of HeLa cells to waters incubated with the modified samples was observed. Finally, the corrosion rate reduced sharply from 856.6 to 0.119 MPY after superhydrophobic modifications, which is an excellent stable corrosion inhibition property. (c) 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2220-2233, 2016.
  •  
49.
  • Montazerolghaem, Maryam, 1985-, et al. (författare)
  • Sustained release of simvastatin from premixed injectable calcium phosphate cement
  • 2014
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 102:2, s. 340-347
  • Tidskriftsartikel (refereegranskat)abstract
    • Locally applied simvastatin is known to promote bone regeneration; however, the lack of suitable delivery systems has restricted its clinical use. In this study we demonstrate for the first time the use ofpremixed acidic calcium phosphate cement (CPC) as a delivery system for water-solubilizedsimvastatin. Freeze-dried simvastatin -hydroxy acid (SVA) was added to the premixed cement paste in four different doses (1, 0.5, 0.25, and 0 mg SVA/g cement). The addition of the drug did not alter thecement setting time (38 min), compression strength (5.54 MPa), or diametral tensile strength (2.62 MPa). In a release study conducted in phosphate buffered saline at 37 degrees C, a diffusion-controlledrelease was observed for over a week. Furthermore, the osteogenic effect of the released SVA was demonstrated in vitro. Cell proliferation, alkaline phosphatase activity, and mineralization were assayed after incubation with cement extracts. The lower doses of SVA (0.5 and 0.25 mg SVA/g cement) showed an approximately fourfold increase in mineralization as compared to the control. In conclusion, our findings suggest that premixed acidic CPC is a good option for local delivery of SVA, due to its ability of slowly releasing the drug, leading to a prolonged stimulation of osteogenesis.
  •  
50.
  • Moroni, Lorenzo, et al. (författare)
  • Micropatterned hot-embossed polymeric surfaces influence cell proliferation and alignment
  • 2009
  • Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88A:3, s. 644-653
  • Tidskriftsartikel (refereegranskat)abstract
    • Micropatterning is a powerful technique to custom-make and precisely control the surface topography of materials, which is determinant for a better interaction with cells. A modification of conventional micropatterning is proposed here to fabricate textured film from stiff and sticky polymers such as poly(lactide(s)-co-glycolide(s)) (PLGA) without the use of supports or solvents. Micropatterned PLGA films with square pits varying in height and channels varying in width were made to study the influence of these topographical parameters on human fibroblasts proliferation, morphology, and alignment. With increasing the square pit height, the cell attachment efficiency increased. After 10 days of culture the micropatterned films supported a significantly higher cell proliferation than smooth films. In particular, cell growth was highly stimulated in 150-mu m-wide channels. Fibroblasts were spread with a typical spindle shape in all the films. Cell spreading increased with increasing the textured dimensions. A random cell organization was found for smooth and for square pit samples, and a high alignment was observed along the 150-mu m-wide channels. Smaller and bigger channels did not support substantial cell growth, suggesting a possible "recognition" mechanism of the cells for optimal organization. These findings could be useful in tissue engineering applications where higher proliferation rates and eventual random or unidimensional alignments of cells are desirable. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 88A: 644-653, 2009
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