| 1. |
- Abramo, Antonio, et al.
(författare)
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Osteotomy of distal radius fracture malunion using a fast remodeling bone substitute consisting of calcium sulphate and calcium phosphate.
- 2010
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Ingår i: Journal of biomedical materials research. Part B, Applied biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 92:1, s. 281-6
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Tidskriftsartikel (refereegranskat)abstract
- Malunion after a distal radius fracture can be treated with an osteotomy of the distal radius. Autologous iliac crest bone graft is often used to fill the gap, but the procedure is associated with donor site morbidity. In this study a novel fast resorbing biphasic bone substitute consisting of a mixture of calcium sulphate and calcium phosphate is used (Cerament BoneSupport AB, Sweden). Fifteen consecutive patients, with a mean age of 52 (27-71) years were included. All had a malunion after a distal radius fracture and underwent an osteotomy. A fragment specific fixation system, TriMed (TriMed, Valencia, CA), consisting of a Buttress Pin and a Radial Pin Plate were used for fixation and a calcium sulphate and calcium phosphate mixture as bone substitute. The patients were followed for 1 year. Grip strength increased from 61 (28-93)% of the contralateral hand to 85 (58-109)%, p < 0.001. DASH scores decreased from 37 (22-61) to 24 (2-49) p = 0.003. Radiographically all osteotomies healed. An increase of ulnar variance was noted during healing from 1.8 mm immediately postoperatively to 2.6 mm at final follow up. Osteotomy can increase grip strength and decease disability after a malunited fracture. In the present series the bone substitute was replaced by bone, but a minor loss of the achieved radiographic correction was noted in some patients during osteotomy healing. A more rigid fixation may improve the radiographic outcome with this kind of bone substitute.
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| 2. |
- Alenezi, Ali, et al.
(författare)
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Controlled release of Clarithromycin from PLGA microspheres enhances bone regeneration in rabbit calvaria defects
- 2017
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 106:1, s. 201-208
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the controlled release effect of Clarithromycin loaded in PLGA microspheres in a rabbit calvaria defect model. Methods: Clarithromycin-loaded PLGA microspheres (MSPs) were formulated by modified O/W single emulsion/solvent evaporation method. After characterization, in vivo animal experiment was conducted. Four critical size bone defects were created in the calvaria of New Zealand White rabbits (n=21, n=7/time point). The bone defects were randomly designated to 4 groups: Group 1: No augmentation (sham), Group 2: beta-Tricalcium phosphate (β-TCP), Group 3: beta-Tricalcium phosphate (β-TCP) with 0.12 µg clarithromycin, and Group 4: beta-Tricalcium phosphate (β-TCP) with 6.12 µg PLGA microspheres (loaded with 0.12 µg clarithromycin). After 2, 4 and 12 weeks of healing, the levels of bone regeneration were evaluated using micro- computed tomography and histology. Results: The average size of the PLGA microspheres was 26.38 μm that showed 94% encapsulation efficacy with clarithromycin. Clarithromycin release from PLGA microspheres revealed sustained release for around 4 weeks with approximately 50% release of clarithromycin during the first week. In the histological analysis, new bone formation was evident at 2 and 4 weeks of healing in all groups and bone formation increased as a function of healing time in vivo. At 12 weeks, Group 4 showed significantly higher amount of newly formed bone compared to Group 1 (p=0,002). Moreover, during the micro CT exam, Group 4 expressed significantly higher bone formation compared to Group 1 at all time points tested (p=0.00, 0.014, and 0.002 in 2, 4, and 12 weeks, respectively). Conclusions: PLGA microspheres demonstrated initial burst release of clarithromycin followed by a sustained release profile. The in vivo findings showed that β-TCP with clarithromycin-loaded microspheres can enhance bone formation in bone defects.
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| 3. |
- Apelgren, Peter, et al.
(författare)
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Long-term in vivo integrity and safety of3D-bioprinted cartilaginous constructs
- 2021
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Ingår i: Journal of Biomedical Materials Research Part B-Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 109:1, s. 126-136
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Tidskriftsartikel (refereegranskat)abstract
- Long-term stability and biological safety are crucial for translation of 3D-bioprinting technology into clinical applications. Here, we addressed the long-term safety and stability issues associated with 3D-bioprinted constructs comprising a cellulose scaffold and human cells (chondrocytes and stem cells) over a period of 10 months in nude mice. Our findings showed that increasing unconfined compression strength over time significantly improved the mechanical stability of the cell-containing constructs relative to cell-free scaffolds. Additionally, the cell-free constructs exhibited a mean compressive stress and stiffness (compressive modulus) of 0.04 +/- 0.05 MPa and 0.14 +/- 0.18 MPa, respectively, whereas these values for the cell-containing constructs were 0.11 +/- 0.08 MPa (p= .019) and 0.53 +/- 0.59 MPa (p= .012), respectively. Moreover, histomorphologic analysis revealed that cartilage formed from the cell-containing constructs harbored an abundance of proliferating chondrocytes in clusters, and after 10 months, resembled native cartilage. Furthermore, extension of the experiment over the complete lifecycle of the animal model revealed no signs of ossification, fibrosis, necrosis, or implant-related tumor development in the 3D-bioprinted constructs. These findings confirm the in vivo biological safety and mechanical stability of 3D-bioprinted cartilaginous tissues and support their potential translation into clinical applications.
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| 4. |
- Ardlin, Berit I., et al.
(författare)
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Corrosion of dental nickel-aluminum bronze with a minor gold content-mechanism and biological impact
- 2009
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - Malden : Wiley-Blackwell. - 1552-4973 .- 1552-4981. ; 88B:2, s. 465-473
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To study corrosion and to evaluate biological effects in vitro of corrosion products of a copper-aluminum-nickel alloy with 2% gold. Methods: The alloy NPGTM+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; and Mn:1.7 was characterized. Static immersion in acidic saline, pH 2.2-2.4, was used to determine release of metallic elements in a milieu simulating the condition of plaque build-up in interproximal areas of the tooth. Corrosion and surface reactions in saline and artificial saliva were studied by electrochemical techniques including registration of open-circuit-potentials, polarization curves and impedance spectra. Extracts were made in cell culture media and acidic saline and used for MTT test for cytotoxicity and HET-CAM method for irritation. Results: The mean amount of elements released in the acidic saline were in g cm-2 : Cu:632; Al:210; Ni:144; Fe:122; Zn:48; Mn:52. No protective film was formed on the surface of the alloy, as extensive corrosion was observed in both saline and artificial saliva. The corrosion rate was higher in saline than in artificial saliva. Acidic extracts of the alloy diluted up to 64 times reduced cell viability with 80% or more. The extract induced coagulation of the blood vessels of the CAM and was rated as moderate irritant solution. Significance: The nickel-aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity.
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| 5. |
- Arvidsson, Anna, 1973, et al.
(författare)
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Comparing and visualizing titanium implant integration in rat bone using 2D and 3D techniques
- 2015
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 103:1, s. 12-20
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to compare the osseointegration of grit-blasted implants with and without a hydrogen fluoride treatment in rat tibia and femur, and to visualize bone formation using state-of-the-art 3D visualization techniques. Grit-blasted implants were inserted in femur and tibia of 10 Sprague-Dawley rats (4 implants/rat). Four weeks after insertion, bone implant samples were retrieved. Selected samples were imaged in 3D using Synchrotron Radiation-based CT (SRCT). The 3D data was quantified and visualized using two novel visualization techniques, thread fly-through and 2D unfolding. All samples were processed to cut and ground sections and 2D histomorphometrical comparisons of bone implant contact (BIC), bone area (BA), and mirror image area (MI) were performed. BA values were statistically significantly higher for test implants than controls (p<0.05), but BIC and MI data did not differ significantly. Thus, the results partly indicate improved bone formation at blasted and hydrogen fluoride treated implants, compared to blasted implants. The 3D analysis was a valuable complement to 2D analysis, facilitating improved visualization. However, further studies are required to evaluate aspects of 3D quantitative techniques, with relation to light microscopy that traditionally is used for osseointegration studies. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 12-20, 2015.
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| 6. |
- Arvidsson, Anna, 1973, et al.
(författare)
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Early interactions between leukocytes and three different potentially bioactive titanium surface modifications
- 2011
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 97:2, s. 364-72
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to compare the early interactions between leukocytes and three different surface modifications, suggested as bioactive. Blasted titanium discs were modified by alkali and heat treatment, sodium fluoride treatment, or hydroxyapatite coating. A number of these discs were also immersed in simulated body fluid (SBF) for a week, a treatment which yielded high levels of calcium and phosphate on each surface type. The specimens were exposed for human venous blood for 32 minutes and the respiratory burst response was measured in terms of reactive oxygen species with a luminometer, and coverage of viable cells with a fluorescence microscope after staining steps. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A high respiratory burst response was found for HA coated titanium in comparison with the other surface groups (p < 0.0005). The SBF immersion resulted in an increased respiratory burst response (p < 0.0005) and removed statistically significant differences between the surface groups. Thus, the results in the present study indicate that different titanium surface modifications influence the early inflammatory response differently, and that calcium phosphate compounds increase the inflammatory response.
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| 7. |
- Asplund, Basse, et al.
(författare)
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In vitro degradation and in vivo biocompatibility study of a new linear poly(urethane urea)
- 2008
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Ingår i: Journal of biomedical materials research. Part B: Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 86B:1, s. 45-55
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Tidskriftsartikel (refereegranskat)abstract
- Segmented poly(urethane urea)s (PUUs) with hard segments derived only from methyl 2,6-diisocyantohexanoate (LDI) without the use of a chain extender have previously been described. These materials, which contain hard segments with multiple urea linkages, show exceptionally high strain capability (1600-4700%). In the study reported here, the rate and effect of hydrolysis of these materials were determined for gamma-sterilized and nonsterilized samples. Materials investigated contained PCL, PTMC, P(TMC-co-CL), P(CL-co-DLLA), or P(TMC-co-DLLA) as soft segments and, as well as their mechanical properties, changes in mass, inherent viscosity (IN.), and thermal properties were studied over 20 weeks. Results showed that the degradation rate was dependant on the soft segment structure, with a higher rate of degradation for the polyester-dominating PUUs exhibiting a substantial loss in IN. A tendency of reduction of tensile strength and strain hardening was seen for all samples. Also, loss in elongation at break was detected, for PUU-P(CL-DLLA) it went from 1600% to 830% in 10 weeks. Gamma radiation caused an initial loss in I.V. and induced more rapid hydrolysis compared with nonsterilized samples, except for PUU-PTMC. A cytotoxicity test using human fibroblasts demonstrated that the material supports cell viability. In addition, an in vivo biocompatibility study showed a typical foreign body reaction after I and 6 weeks.
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| 8. |
- Atthoff, Björn, et al.
(författare)
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Polarized protein membrane for high cell seeding efficiency
- 2007
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Ingår i: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 83:2, s. 472-480
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Tidskriftsartikel (refereegranskat)abstract
- A new type of scaffold for tissue engineering was developed to give enhanced cell seeding in three dimensions. A gradient of either collagen or fibrin protein was prepared, supported by a knitted poly(ethylene terephtalate) PET fabric. The membranes were, after hydrolysis and acetic acid wash, submerged in a protein solution for adsorption followed by immersion into a gelling agent. The immediate contact between the protein solution held by the fabric and the gelling agent resulted in a dense, fibrous protein network with pore sizes around 0.5 μm at the surface, and larger pores of 10-50 μm size throughout the interior of the fabric as observed by scanning electron microscopy. By separating the fabric double layers holding this network, a gradient porosity membrane was produced. To evaluate the fractions of cells trapped in the matrix upon seeding, i.e. the seeding efficiency, 500 μl 3T3 fibroblasts cell suspension containing one million cells was seeded by filtering through the gradient protein membrane. For both the collagen and fibrin membranes, the seeding efficiency was ∼93%, which was significantly higher than that of 28% from the corresponding PET fabric without protein immobilization. Attempt to seed cells from the dense side of the protein networks resulted in no cell penetration into the scaffold. Histology on subsequent culture of the cells in the scaffold demonstrated viability and proliferation in three dimensions throughout the scaffold. This new and simple way of producing scaffolds play an important role when the cells are precious or scarce and cell seeding in three dimensions is important.
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| 9. |
- Atthoff, Björn, et al.
(författare)
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Protein adsorption onto polyester surfaces : Is there a need for surface activation?
- 2007
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Ingår i: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 80:1, s. 121-130
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Tidskriftsartikel (refereegranskat)abstract
- Surface hydrolysis of polyester scaffolds is a convenient technique suggested to promote protein adsorption for improving cell attachment. We have, therefore, investigated the effect of hydrolysis of polyester surfaces for protein adsorption to clarify the conditions needed. Three polyesters, poly(ethylene terephthalate) (PET), poly(lactic acid) (PLA), and poly(glycolic acid) (PGA), were selected. Adsorption was investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and quartz crystal microbalance (QCM). Hydrolyzed PET adsorbed significantly more proteins than nonhydrolyzed. Degradable polymers adsorbed at higher rates when the polymers were hydrolyzed prior to adsorption, but the same amount as noehydrolyzed, suggesting spontaneous hydrolysis during the adsorption. XPS shows that hydrolysis prior to absorption for PET results in a surface nitrogen composition of ∼14%, similar to pure protein (16%). Nonhydrolyzed PET surfaces showed only ∼7% nitrogen, indicating protein layers thinner than ∼10 nm. Adsorption to PLA and PGA shows nitrogen contents of 14-15% in both cases. SEM revealed striking differences in morphology of the protein coating. Hydrolyzed or spontaneously hydrolyzable surfaces display a pronounced fibrous structure while nonhydrolyzed surfaces give smooth structures. In combination, the results show that surface hydrolysis increase adsorption rate, but not the amount of proteins on polyesters that degrades in vivo. Surface treatment of nondegradable polyester increases the total amount of proteins and induces the formation of fibrous protein structures. Post hydrolysis treatment by acetic acid, replacing the counter-ion to a proton, further enhances protein attachment. Finally, cell attachment experiments verifies that protein adsorption increase the cell attachment to polyester surfaces.
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| 10. |
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