| 1. |
- Alenezi, Ali, et al.
(author)
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Controlled release of Clarithromycin from PLGA microspheres enhances bone regeneration in rabbit calvaria defects
- 2017
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In: 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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Journal article (peer-reviewed)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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| 2. |
- Arvidsson, Anna, 1973, et al.
(author)
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Comparing and visualizing titanium implant integration in rat bone using 2D and 3D techniques
- 2015
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 103:1, s. 12-20
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Journal article (peer-reviewed)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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| 3. |
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| 4. |
- Björling, Gunilla, et al.
(author)
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Evaluation of central venous catheters coated with a noble metal alloy - A randomized clinical pilot study of coating durability, performance and tolerability
- 2018
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 106:6, s. 2337-2344
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Journal article (peer-reviewed)abstract
- The use of Central Venous Catheters (CVCs) commonly results in complications. Coatings with silver or metal alloys can reduce the risk associated with the use of CVC. We have evaluated the durability of a noble metal coated CVC (the Bactiguard Infectious Protection, BIP CVC) and compared with an uncoated CVC for clinical tolerability (Adverse Events, AEs) and performance, in order to create a baseline for a large future study. Patients undergoing major surgery, randomised at a 2:1 ratio to BIP CVC (n = 22) or standard CVC (n = 12), were catheterized 9 - 12 days, respectively. Adverse events, microbial colonization and metal release were measured.FINDINGS: There were no AEs in the BIP CVC-group, but 5 AEs occurred in 4 patients (1 patient had 2 AEs) in the standard CVC-group, p = 0.011 (whereof 3 were catheter related). The BIP CVC showed an initial release of coating metals in blood (gold, silver and palladium), which rapidly decreased and were far below Permitted Paily Exposure (PDE) for chronical use. The levels of silver concentration were far below those needed to develop microbial resistance. The performance was equal, and there was no difference concerning microbial colonization, for the two CVCs.CONCLUSION: In this pilot study the BIP CVC had significantly lower AEs and showed a comparable performance to the standard CVC. The coating was durable throughout the study length (up to 16 days) and toxicological evaluation showed good safety margins. Larger studies are needed.
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| 5. |
- Eick, Sigrun, et al.
(author)
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Gingipains impair attachment of epithelial cell to dental titanium abutment surfaces
- 2019
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 107:8, s. 2549-2556
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Journal article (peer-reviewed)abstract
- The study investigated in vitro the effect of Porphyromonas gingivalis and its cysteine proteases (gingipains) on epithelial cell adhesion to titanium-zirconium alloy surfaces. Titanium-zirconium discs with a standard machined (M) or chemically modified hydrophilic surface (modM) were coated with lamin-5 and incubated with telomerase-inactivated gingival keratinocytes (TIGK). Three P. gingivalis strains or gingipains were either added simultaneously with TIGK or after TIGK cells were already attached to the disks. Adhered TIGK cells were counted at 24 h. All P. gingivalis strains clearly inhibited adhesion of TIGK cells to M and modM surfaces. Compared with bacteria/gingipain-free TIGK cell cultures, the number of attached TIGK cells was reduced by about 80% and 60% when P. gingivalis was added simultaneously or after TIGK cells were already attached to the disks (each p < 0.01), respectively. Counts of attached cells were similarly reduced when only gingipains were used. Adhesion molecules of TIGK cells, in particular E-cadherin, were cleaved by P. gingivalis. In conclusion, P. gingivalis and gingipains interfere with the adhesion of epithelial cells to titanium-zirconium alloy surfaces by cleaving adhesion molecules, while a chemically modified hydrophilic titanium-zirconium alloy surface did not yield any protection. (c) 2019 Wiley Periodicals, Inc. J Biomed Mater Res B Part B, 2019.
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| 6. |
- Engstrand Unosson, Johanna, et al.
(author)
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An evaluation of methods to determine the porosity of calcium phosphate cements
- 2015
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 103:1, s. 62-71
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Journal article (peer-reviewed)abstract
- The porosity of a material can be determined using a diversity of methods; however, the results from these methods have so far not been compared and analyzed for calcium phosphate cements (CPCs). The aim of this study was to compare a fast and easy method for porosity measurements with some commonly used porosity methods for CPCs. The investigated method is based on the assumption that when a wet cement sample is dried, the volume of the evaporated water is equal to the volume of pores within the cement. Moreover, different methods of drying the cements were evaluated for acidic CPCs. The results showed that drying at room temperature (22°C ±1°C) is preferable, since a phase transformation was observed at higher temperatures. The results also showed that drying for 24 hours in vacuum was sufficient to achieve water free cements. The porosity measured was found to vary between the porosity methods evaluated herein, and to get a complete picture of a cement’s porosity more than one method is recommended. Water evaporation, is, however, a fast and easy method to estimate the porosity of CPCs and could simplify porosity measurements in the future.
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| 7. |
- Galli, Silvia, et al.
(author)
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Magnesium release from mesoporous carriers on endosseus implants does not influence bone maturation at 6 weeks in rabbit bone
- 2017
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In: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 105:7, s. 2118-2125
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Journal article (peer-reviewed)abstract
- ObjectivesThe release of magnesium ions (Mg2+) from titanium surfaces has been shown to boost the initial biological response of peri-implant bone and to increase the biomechanical strength of osseointegration. The objective of the present paper was to investigate if the initial improvement in osseointegration would influence the bone remodeling also during the maturation stage of bone healing. Methods: Titanium implants were coated with mesoporous titania layers and either loaded with Mg2+ (test group) or left untreated (control group). The implants were inserted in the tibiae of 10 New Zealand White rabbits. Osseointegration was assessed after 6 weeks by means of biomechanical testing (RTQ), non-decalcified histology and histomorphometry (BIC%, BA%, NBA%). The expression of genes involved in the bone formation and remodeling was quantified using qPCR. Results: Mg2+ releasing mesoporous titania coatings showed, on average, higher removal torques and histomorphometrical outcomes (RTQ: 17.2 Ncm vs. 15 Ncm; BIC: 38.8% vs. 32.1%; BA%: 71.6% vs. 64%; NBA% 62.5% vs. 54% for the tests vs the controls); however, the differences were not statistically significant. Three osteogenic markers, osteocalcin (OC), collagen 1 alpha 1 (COL1A1), and alkalin phosphatase (ALPL), were respectively 2-fold, 1.53-fold, and 1.13-fold up-regulated in the control group compared to the test. The expression of COL1A1 was particularly high in both groups, while the biomarkers for remodeling and inflammation showed a low expression in both groups. Significance: The results suggested that the initial enhancement in osseointegration induced by magnesium release from mesoporous titania coatings has no detrimental effects during bone maturation.
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| 8. |
- Galli, Silvia, et al.
(author)
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Magnesium release from mesoporous carriers on endosseus implants does not influence bone maturation at 6 weeks in rabbit bone.
- 2017
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 105:7, s. 2118-2125
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: The release of magnesium ions (Mg2+ ) from titanium surfaces has been shown to boost the initial biological response of peri-implant bone and to increase the biomechanical strength of osseointegration. The objective of the present paper was to investigate if the initial improvement in osseointegration would influence the bone remodeling also during the maturation stage of bone healing.METHODS: Titanium implants were coated with mesoporous titania layers and either loaded with Mg2+ (test group) or left untreated (control group). The implants were inserted in the tibiae of 10 New Zealand White rabbits. Osseointegration was assessed after 6 weeks by means of biomechanical testing (RTQ), non-decalcified histology and histomorphometry (BIC%, BA%, NBA%). The expression of genes involved in the bone formation and remodeling was quantified using qPCR.RESULTS: Mg2+ releasing mesoporous titania coatings showed, on average, higher removal torques and histomorphometrical outcomes (RTQ: 17.2 Ncm vs. 15 Ncm; BIC: 38.8% vs. 32.1%; BA%: 71.6% vs. 64%; NBA% 62.5% vs. 54% for the tests vs the controls); however, the differences were not statistically significant. Three osteogenic markers, osteocalcin (OC), collagen 1 alpha 1 (COL1A1), and alkalin phosphatase (ALPL), were respectively 2-fold, 1.53-fold, and 1.13-fold up-regulated in the control group compared to the test. The expression of COL1A1 was particularly high in both groups, while the biomarkers for remodeling and inflammation showed a low expression in both groups.SIGNIFICANCE: The results suggested that the initial enhancement in osseointegration induced by magnesium release from mesoporous titania coatings has no detrimental effects during bone maturation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2118-2125, 2017.
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| 9. |
- Gil, Luiz F., et al.
(author)
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Progressive plateau root form dental implant osseointegration : a human retrieval study
- 2015
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 103:6, s. 1328-1332
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Journal article (peer-reviewed)abstract
- Although preclinical and sparse human histology retrieval studies have shown that the interface between implant and bone is constantly remodeling, no human retrieval database has been developed to determine the effect of functional loading time and other clinical/implant design variables on osseointegration. The present study tested the hypothesis that bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) increase over functional loading time around dental implants. Due to prosthetic retreatment reasons, 93 human implant retrievals from the same manufacturer (Bicon LLC, Boston, MA, USA) were obtained over a period of approximately 15 years. The retrieved implants were under functional loading from 120 days to approximate to 18 years and were histomorphologic/metrically evaluated. BIC/BAFO were assessed as a function of multiple independent variables: implant surface type, diameter, length, jaw (maxilla/mandible), region (anterior/posterior), and time of functional loading. The results showed that both BIC and BAFO increased over time independently of implant design/clinical variables, supporting the postulated hypothesis. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1328-1332, 2015.
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| 10. |
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| 11. |
- Jimbo, Ryo, et al.
(author)
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Regeneration of the cementum and periodontal ligament using local BDNF delivery in class II furcation defects
- 2018
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 106:4, s. 1611-1617
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Journal article (peer-reviewed)abstract
- Periodontal furcation defects are usually addressed by the placement of a physical barrier which may limit the regenerative potential of periodontal wounds. This study morphometrically quantified the regenerative effect of brain-derived neurotrophic factor (BDNF) in furcation defects in a non-human primate model. Grade II furcation defects (with and without induced inflammation prior to surgery) were created on the first and second molars of eight non-human primates. Defects were treated with open flap debridement and subsequently filled with either: Group A; BDNF (500 µg mL−1) in high-molecular weight-hyaluronic acid (HMW-HA), Group B; BDNF (50 µg mL−1) in HMW-HA, Group C; HMW-HA acid only, Group D; unfilled defect, or Group E; BDNF (500 µg mL−1) in saline. Periodontal wound healing was observed every 2 weeks by computed-tomography. At 11 weeks all animals were sacrificed and maxillary and mandibular block biopsies were referred for nondecalcified histology. Linear measurements of new cementum (cellular and acellular) and periodontal ligament (PDL) formation were performed. Computerized-tomography reconstruction and software quantification demonstrated successful bone fill for all groups. However, histometric assessment demonstrated significantly higher level of total periodontal regeneration for the 500 µg mL−1 BDNF HMW-HA relative to all other groups. No significant differences in cementogenesis were observed among groups. Significantly higher acellular cementum formation was observed for sites where inflammation was not induced prior to surgical procedures. While all groups experienced similar bone fill and cementogenesis, the 500 µg mL−1 BDNF HMW-HA appeared to most effectively repair PDL (minimum increase of ∼22% relative to all groups; over 200% relative to unfilled defects).
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| 12. |
- Krontiras, P., et al.
(author)
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Adipogenic differentiation of stem cells in three-dimensional porous bacterial nanocellulose scaffolds
- 2015
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In: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 103:1, s. 195-203
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Journal article (peer-reviewed)abstract
- There is an increased interest in developing adipose tissue for in vitro and in vivo applications. Current two-dimensional (2D) cell-culture systems of adipocytes are limited, and new methods to culture adipocytes in three-dimensional (3D) are warranted as a more life-like model to study metabolic diseases such as obesity and diabetes. In this study, we have evaluated different porous bacterial nanocellulose scaffolds for 3D adipose tissue. In an initial pilot study, we compared adipogenic differentiation of mice mesenchymal stem cells from a cell line on 2D and 3D scaffolds of bacterial nanocellulose. The 3D scaffolds were engineered by crosslinking homogenized cellulose fibrils using alginate and freeze drying the mixture to obtain a porous structure. Quenching the scaffolds in liquid nitrogen resulted in smaller pores compared to slower freezing using isopropanol. We found that on 2D surfaces, the cells were scarcely distributed and showed limited formation of lipid droplets, whereas cells grown in macroporous 3D scaffolds contained more cells growing in clusters, containing large lipid droplets. All four types of scaffolds contained a lot of adipocytes, but scaffolds with smaller pores contained larger cell clusters than scaffolds with bigger pores, with viable adipocytes present even 4 weeks after differentiation. Scaffolds with lower alginate fractions retained their pore integrity better. We conclude that 3D culturing of adipocytes in bacterial nanocellulose macroporous scaffolds is a promising method for fabrication of adipose tissue as an in vitro model for adipose biology and metabolic disease.
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| 13. |
- Lahens, Bradley, et al.
(author)
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The effect of osseodensification drilling for endosteal implants with different surface treatments : A study in sheep.
- 2019
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 107:3, s. 615-623
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Journal article (peer-reviewed)abstract
- This study investigated the effects of osseodensification drilling on the stability and osseointegration of machine-cut and acid-etched endosteal implants in low-density bone. Twelve sheep received six implants inserted into the ilium, bilaterally (n = 36 acid-etched, and n = 36 as-machined). Individual animals received three implants of each surface, placed via different surgical techniques: (1) subtractive regular-drilling (R): 2.0 mm pilot, 3.2 and 3.8 mm twist drills); (2) osseodensification clockwise-drilling (CW): Densah Bur (Versah, Jackson, MI) 2.0 mm pilot, 2.8, and 3.8 mm multifluted tapered burs; and (3) osseodensification counterclockwise-drilling (CCW) Densah Bur 2.0 mm pilot, 2.8 mm, and 3.8 mm multifluted tapered burs. Insertion torque was higher in the CCW and CW-drilling compared to the R-drilling (p < 0.001). Bone-to-implant contact (BIC) was significantly higher for CW (p = 0.024) and CCW-drilling (p = 0.006) compared to the R-drilling technique. For CCW-osseodensification-drilling, no statistical difference between the acid-etched and machine-cut implants at both time points was observed for BIC and BAFO (bone-area-fraction-occupancy). Resorbed bone and bone forming precursors, preosteoblasts, were observed at 3-weeks. At 12-weeks, new bone formation was observed in all groups extending to the trabecular region. In low-density bone, endosteal implants inserted via osseodensification-drilling presented higher stability and no osseointegration impairments compared to subtractive regular-drilling technique, regardless of evaluation time or implant surface. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000-000, 2018.
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| 14. |
- Larsson, Lena, 1969, et al.
(author)
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When epigenetics meets bioengineering-A material characteristics and surface topography perspective
- 2018
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In: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 106:5, s. 2065-2071
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Research review (peer-reviewed)abstract
- © 2017 Wiley Periodicals, Inc. The field of tissue engineering and regenerative medicine (TE/RM) involves regeneration of tissues and organs using implantable biomaterials. The term epigenetics refers to changes in gene expression that are not encoded in the DNA sequence, leading to remodeling of the chromatin and activation or inactivation of gene expression. Recently, studies have demonstrated that these modifications are influenced not only by biological cues but also by mechanical and topographical signals. This review highlights the current knowledge on emerging approaches in TE/RM with a focus on the effect of materials and topography on the epigenetic expression pattern in cells with potential impacts on modulating regenerative biology.
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| 15. |
- Leino, Mattias, et al.
(author)
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Human embryonic stem cell dispersion in electrospun PCL fiber scaffolds by coating with laminin-521 and E-cadherin-Fc
- 2018
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 106:3, s. 1226-1236
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Journal article (peer-reviewed)abstract
- Advances in human pluripotent cell cultivation and differentiation protocols have led to production of stem cell-derived progenitors as a promising cell source for replacement therapy. Three-dimensional (3-D) culture is a better mimic of the natural niche for stem cells and is widely used for disease modeling. Here, we describe a nonaggregate culture system of human embryonic stem cells inside electrospun polycaprolactone (PCL) fiber scaffolds combined with defined extracellular proteins naturally occurring in the stem cell niche. PCL fiber scaffolds coated with recombinant human laminin-521 readily supported initial stem cell attachment and growth from a single-cell suspension. The combination of recombinant E-cadherin-Fc and laminin-521 further improved cell dispersion rendering a uniform cell population. Finally, we showed that the cells cultured in E-cadherin-Fc- and laminin-521-coated PCL scaffolds could differentiate into all three germ layers. Importantly, we provided a chemically defined 3-D system in which pluripotent stem cells grown and differentiated avoiding the formation of cell aggregates.
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| 16. |
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| 17. |
- Peeters, Elien, et al.
(author)
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An antibiofilm coating of 5-aryl-2-aminoimidazole covalently attached to a titanium surface
- 2019
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 107:6, s. 1908-1919
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Journal article (peer-reviewed)abstract
- Biofilms, especially those formed by Staphylococcus aureus, play a key role in the development of orthopedic implant infections. Eradication of these infections is challenging due to the elevated tolerance of biofilm cells against antimicrobial agents. In this study, we developed an antibiofilm coating consisting of 5-(4-bromophenyl)-N-cyclopentyl-1-octyl-1H-imidazol-2-amine, designated as LC0024, covalently bound to a titanium implant surface (LC0024-Ti). We showed in vitro that the LC0024-Ti surface reduces biofilm formation of S. aureus in a specific manner without reducing the planktonic cells above the biofilm, as evaluated by plate counting and fluorescence microscopy. The advantage of compounds that only inhibit biofilm formation without affecting the viability of the planktonic cells, is that reduced development of bacterial resistance is expected. To determine the antibiofilm activity of LC0024-Ti surfaces in vivo, a biomaterial-associated murine infection model was used. The results indicated a significant reduction in S. aureus biofilm formation (up to 96%) on the LC0024-Ti substrates compared to pristine titanium controls. Additionally, we found that the LC0024-Ti substrates did not affect the attachment and proliferation of human cells involved in osseointegration and bone repair. In summary, our results emphasize the clinical potential of covalent coatings of LC0024 on titanium implant surfaces to reduce the risk of orthopedic implant infections.
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| 18. |
- Pujari-Palmer, Shiuli, et al.
(author)
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Reduced oxidative stress in primary human cells by antioxidant released from nanoporous alumina
- 2016
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 104:3, s. 568-575
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Journal article (peer-reviewed)abstract
- Nanoporous alumina elicits different inflammatory responses dependent on pore size, such as increased complement activation and reactive oxygen species (ROS) production, on 200 versus 20 nm pores. In this study, we attempt to further modulate inflammatory cell response by loading nanoporous alumina membranes (20, 100, and 200 nm pores), with an antioxidant, Trolox, for controlled drug release. For mononuclear cells (MNC) no difference in cell response, due to pore size, was seen when cultured on nonloaded membranes. However, when exposed to membranes loaded with Trolox, 100 uM was enough to quench ROS by more than 95% for all pore sizes. Polymorphonuclear cells (PMNC) produced significantly more ROS when exposed to 20 versus 100 nm pores. For Trolox loaded membranes, this trend reversed, due to slower release of antioxidant from the 20 nm pores. Furthermore, Trolox exhibited a unique effect on PMNCs that has not previously been reported: It delayed the production of ROS in a manner distinct from antioxidant activity. The present study confirms that nanoporous alumina is a suitable vehicle for drug delivery, and that Trolox can successfully modulate the inflammatory response of both MNC and PMNCs.
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| 19. |
- Sun, Kwang-Hsiao, et al.
(author)
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In vivo study of alginate hydrogel conglutinating cells to polycaprolactone vascular scaffolds fabricated by electrospinning
- 2017
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : WILEY. - 1552-4973 .- 1552-4981. ; 105:8, s. 2443-2454
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Journal article (peer-reviewed)abstract
- Objective The aim of this study was to explore an innovative cell-seeding technology applied on artificial vascular scaffolds. Methods Scaffolds were fabricated by electrospinning polycaprolactone (PCL) and seeded with rat endothelial progenitor cells differentiated from adipose-derived stem cells. Then, we modified the PCL scaffolds through the use of alginate hydrogel conglutinating cells (AHCC), a blank alginate hydrogel coating (BAHC), and natural sedimentation seeding cells (NSSC). The blank PCL (BP) scaffolds without any modifications were considered the blank control group. After modification, the scaffolds were implanted in a rat model. The implanted scaffolds were harvested and observed using histological and immunohistochemical methods and scanning electron microscopy (SEM) at 1, 2, and 4weeks after implantation, respectively. Results The best regeneration and configuration of the endothelium tissue and the most similar morphology to that of natural endangium was observed qualitatively in the AHCC scaffolds. The BP scaffolds had qualitatively the worst regeneration and configuration and the most dissimilar morphology at the same time point. In the AHCC group, cells could adhere directly on the inner surface of the vascular scaffolds, eliminating the time delay via the NSSC method prior to cell adhesion. Conclusion AHCC are an effective method for seeding cells on vascular scaffolds and can eliminate the time delay for cell adhesion. (C) 2016 Wiley Periodicals, Inc.
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| 20. |
- Suñer, Silvia, et al.
(author)
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Ultrahigh molecular weight polyethylene/graphene oxide nanocomposites: Wear characterization and biological response to wear particles
- 2018
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 106:1, s. 183-190
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Journal article (peer-reviewed)abstract
- In the field of total joint replacements, polymer nanocomposites are being investigated as alternatives to ultrahigh molecular weight polyethylene (UHMWPE) for acetabular cup bearings. The objective of this study was to investigate the wear performance and biocompatibility of UHMWPE/graphene oxide (GO) nanocomposites. This study revealed that low concentrations of GO nanoparticles (0.5 wt %) do not significantly alter the wear performance of UHMWPE. In contrast, the addition of higher concentrations (2 wt %) led to a significant reduction in wear. In terms of biocompatibility, UHMWPE/GO wear particles did not show any adverse effects on L929 fibroblast and PBMNC viability at any of the concentrations tested over time. Moreover, the addition of GO to a UHMWPE matrix did not significantly affect the inflammatory response to wear particles. Further work is required to optimize the manufacturing processes to improve the mechanical properties of the nanocomposites and additional biocompatibility testing should be performed to understand the potential clinical application of these materials
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| 21. |
- Törne, Karin, et al.
(author)
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Degradation of zinc in saline solutions, plasma, and whole blood
- 2016
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 104:6, s. 1141-1151
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Journal article (peer-reviewed)abstract
- The initial degradation of zinc has been investigated through exposures to simulated and real body fluids of increasing complexity: phosphate buffered saline (PBS), Ringer's saline solution, human plasma, and whole blood. Real body fluids were used to close the electrolyte gap between simulated and in vivo environment. Polarization of zinc in whole blood show a passive response not present in other electrolytes. The analysis shows a decrease in corrosion rate with time for plasma and whole blood and an increase for PBS and Ringer's. During exposure to plasma and whole blood a bi-layered corrosion product with poor adherence was formed over a uniformly corroding surface. The corrosion products comprise a mixture of inorganic material and biomolecules. Samples degrading in PBS were prone to localized corrosion and formed thick porous corrosion products of primarily zinc phosphates while in Ringer's solution a gel like layer of zinc carbonate was formed over an interface with shallow pits. The use of whole blood or plasma as electrolytes for short term in vitro evaluation of potential biodegradable metals may provide an improved understanding of the behavior in vivo, while Ringer's solution is preferred over PBS for long term degradation studies of zinc.
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| 22. |
- Törne, Karin, et al.
(author)
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The influence of buffer system and biological fluids on the degradation of magnesium
- 2017
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 105:6, s. 1490-1502
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Journal article (peer-reviewed)abstract
- The influence of frequently used buffer system 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) compared to CO2/HCO3- on the corrosion of magnesium is investigated. Samples were immersed in simulated body fluid (m-SBF) while monitored by electrochemical impedance spectroscopy (EIS) for up to 30 days. In CO2/HCO3- the initial corrosion rate was 0.11 mm yr-1. An inner protective layer of magnesium oxide was formed within the first 30 min exposure and subsequently covered by an outer layer of apatite within 24 h. The corrosion mechanism thereafter is best described as passive pitting with a porosity of ∼10%. Using HEPES as buffer agent increased the corrosion rate to 3.37 mm yr-1. Cross sectional microscopy show a porous outer corrosion layer allowing rapid diffusion of aggressive ions through the film. Here the EIS results are best described by an active pitting model with an inner layer 5 to 10 times less protective compared to the inner layer formed without HEPES. Further the suitability of human whole blood and plasma as in vitro models for Mg degradation was evaluated. Mg corrosion caused coagulation after 24 h in both biological fluids. The corrosion during the first 24 h is similar to the corrosion in m-SBF with HEPES.
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| 23. |
- Unosson, Johanna, et al.
(author)
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Brushite foamsthe effect of Tween (R) 80 and Pluronic (R) F-127 on foam porosity and mechanical properties
- 2016
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 104:1, s. 67-77
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Journal article (peer-reviewed)abstract
- Resorbable calcium phosphate based bone void fillers should work as temporary templates for new bone formation. The incorporation of macropores with sizes of 100 -300 mu m has been shown to increase the resorption rate of the implant and speed up bone ingrowth. In this work, macroporous brushite cements were fabricated through foaming of the cement paste, using two different synthetic surfactants, Tween (R) 80 and Pluronic (R) F-127. The macropores formed in the Pluronic samples were both smaller and less homogeneously distributed compared with the pores formed in the Tween samples. The porosity and compressive strength (CS) were comparable to previously developed hydroxyapatite foams. The cement foam containing Tween, 0.5M citric acid in the liquid, 1 mass% of disodium dihydrogen pyrophosphate mixed in the powder and a liquid to powder ratio of 0.43 mL/g, showed the highest porosity values (76% total and 56% macroporosity), while the CS was >1 MPa, that is, the hardened cement could be handled without rupture of the foamed structure. The investigated brushite foams show potential for future clinical use, both as bone void fillers and as scaffolds for in vitro bone regeneration.
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| 24. |
- Wei, Zheng, et al.
(author)
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Can gamma irradiation during radiotherapy influence the metal release process for biomedical CoCrMo and 316L alloys?
- 2018
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 106:7, s. 2673-2680
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Journal article (peer-reviewed)abstract
- The extent of metal release from implant materials that are irradiated during radiotherapy may be influenced by irradiation-formed radicals. The influence of gamma irradiation, with a total dose of relevance for radiotherapy (e.g., for cancer treatments) on the extent of metal release from biomedical stainless steel AISI 316L and a cobalt-chromium alloy (CoCrMo) was investigated in physiological relevant solutions (phosphate buffered saline with and without 10 g/L bovine serum albumin) at pH 7.3. Directly after irradiation, the released amounts of metals were significantly higher for irradiated CoCrMo as compared to nonirradiated CoCrMo, resulting in an increased surface passivation (enhanced passive conditions) that hindered further release. A similar effect was observed for 316L showing lower nickel release after 1 h of initially irradiated samples as compared to nonirradiated samples. However, the effect of irradiation (total dose of 16.5 Gy) on metal release and surface oxide composition and thickness was generally small. Most metals were released initially (within seconds) upon immersion from CoCrMo but not from 316L. Albumin induced an increased amount of released metals from AISI 316L but not from CoCrMo. Albumin was not found to aggregate to any greater extent either upon gamma irradiation or in the presence of trace metal ions, as determined using different light scattering techniques. Further studies should elucidate the effect of repeated friction and fractionated low irradiation doses on the short- and long term metal release process of biomedical materials.
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| 25. |
- Zaborowska, Magdalena, 1984, et al.
(author)
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Bacteria-material surface interactions : methodological development for the assessment of implant surface induced antibacterial effects.
- 2015
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 103:1, s. 179-187
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Journal article (peer-reviewed)abstract
- The choice of material for implanted prostheses is of great importance concerning bacterial colonization and biofilm formation. Consequently, methods to investigate bacterial behavior are needed in order to develop new infection resistant surfaces. In this study, different methodological setups were used to evaluate the antimicrobial effect of photocatalytic titanium oxide and silver surfaces. Biofilm formation and eradication under static and dynamic culture conditions were studied with the use of the following analytical techniques: viable colony-forming unit (CFU) counting, imprinting, fluorescence, and bioluminescence. The present study demonstrates that different methods are needed in order to evaluate the prophylactic and treatment effects on planktonic and biofilm bacteria and to assess the antimicrobial effect of different surface treatments/coatings. Choosing the right antibacterial testing model for the specific application is also of great importance. Both in situ approaches and indirect methods provide valuable complementary information. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.
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| 26. |
- Zaborowska, Magdalena, 1984, et al.
(author)
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Biofilm formation and antimicrobial susceptibility of staphylococci and enterococci from osteomyelitis associated with percutaneous orthopaedic implants.
- 2017
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In: Journal of biomedical materials research. Part B, Applied biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 105:8, s. 2630-2640
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Journal article (peer-reviewed)abstract
- Staphylococci and enterococci account for most deep infections associated with bone-anchored percutaneous implants for amputation treatment. Implant-associated infections are difficult to treat; therefore, it is important to investigate if these infections have a biofilm origin and to determine the biofilm antimicrobial susceptibility to improve treatment strategies. The aims were: (i) to test a novel combination of the Calgary biofilm device and a custom-made susceptibility MIC plate (Sensititre(®) ), (ii) to determine the biofilm formation and antimicrobial resistance in clinical isolates causing implant-associated osteomyelitis, and (iii) to describe the associated clinical outcome. Enterococci and staphylococci were characterized by microtitre plate assay, Congo Red Agar plate test, and PCR. Biofilm susceptibility to 10 antimicrobials and its relationship to treatment outcomes were determined. The majority of the strains produced biofilm in vitro showing inter- and intraspecies differences. Biofilms showed a significantly increased antimicrobial resistance compared with their planktonic counterparts. Slime-producing strains tolerated significantly higher antimicrobial concentrations compared with non-producers. All seven staphylococcal strains carried ica genes, but two did not produce slime. The degree of biofilm formation and up-regulated antibiotic resistance may translate into a variable risk of treatment failure. This new method set-up allows for the reproducible determination of minimum biofilm eradication concentration of antimicrobial agents, which may guide future antimicrobial treatment decisions in orthopaedic implant-associated infection. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.
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| 27. |
- Öhrnell Malekzadeh, Behnosh, et al.
(author)
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Insulin released from titanium discs with insulin coatings- kinetics and biological activity
- 2017
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 105:7, s. 1847-1854
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Journal article (peer-reviewed)abstract
- Local administration of insulin from a titanium surface has been demonstrated to increase bone formation in non-diabetic rats. The authors hypothesised that insulin was released from the titanium surface and with preserved biological activity after the release. Thus, in the present in vitro study, human recombinant insulin was immobilized onto titanium discs, and the insulin release kinetics was evaluated using Electro-chemiluminescence immunoassay. Neutral Red uptake assay and a mineralization assay were used to evaluate the biological effects of insulin on human osteoblast-like MG-63 cells. The results confirmed that insulin was released from titanium surfaces during a six-week period. Furthermore, etching the disc prior to insulin coating, thickening of the insulin coating and incubation of the discs in serum-enriched cell culture medium increased the release. Another interesting finding was that longer storage time decreased the release of insulin. The released insulin had retained its biological activity, as demonstrated by the significant increase in cell number and a stimulated mineralization process, upon exposure to released insulin.
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| 28. |
- Hedberg, Yolanda, Docent, 1985-, et al.
(author)
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Mechanistic insight on the combined effect of albumin and hydrogen peroxide on surface oxide composition and extent of metal release from Ti6Al4V
- 2019
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In: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : WILEY. - 1552-4973. ; 107:3, s. 858-867
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Journal article (peer-reviewed)abstract
- The titanium–aluminium (6 wt%)–vanadium (4 wt%) (Ti6Al4V) alloy is widely used as an orthopedic and dental implant material due to its high corrosion resistance in such environments. The corrosion resistance is usually determined by means of electrochemical methods, which may not be able to detect other chemical surface reactions. Literature findings report a synergistic effect of the combination of the abundant protein albumin and hydrogen peroxide (H 2 O 2 ) on the extent of metal release and corrosion of Ti6Al4V. The objectives of this study were to gain further mechanistic insight on the interplay of H 2 O 2 and albumin on the metal release process of Ti6Al4V with special focus on (1) kinetics and (2) H 2 O 2 and albumin concentrations. This was accomplished mainly by metal release and surface oxide composition investigations, which confirmed the combined effect of H 2 O 2 and albumin on the metal release process, although not detectable by electrochemical open circuit potential measurements. A concentration of 30 mM H 2 O 2 induced substantial changes in the surface oxide characteristics, an oxide which became thicker and enriched in aluminum. Bovine serum albumin (BSA) seemed to be able to deplete this aluminum content from the outermost surface or at least to delay its surface enrichment. This effect increased with increased BSA concentration, and for time periods longer than 24 h. This study hence suggests that short-term (accelerated) corrosion resistance measurements are not sufficient to predict potential health effects of Ti6Al4V alloys since also chemical dissolution mechanisms play a large role for metal release, possibly in a synergistic way.
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| 29. |
- Schmitt, V. H., et al.
(author)
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Tissue response to five commercially available peritoneal adhesion barriers-A systematic histological evaluation
- 2018
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In: Journal of Biomedical Materials Research Part B-Applied Biomaterials. - : Wiley. - 1552-4973. ; 106:2, s. 598-609
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Journal article (peer-reviewed)abstract
- Separating wounded serosa by physical barriers is the only clinically approved adjunct for postoperative adhesion prevention. Since the optimal adhesion barrier has not been found, it is essential to improve our pathogenic understanding of adhesion formation and to compare the effects of different barrier materials on tissue and cells. Wistar rats underwent standardized peritoneal damage and were treated either with Seprafilm, Adept, Intercoat, Spraygel, SupraSeal or remained untreated as a control. 14 days postoperatively, the lesions were explanted and histomorphologically analyzed using the European ISO score to evaluate material implants. Striking differences between the material groups were present regarding the inflammation, fibrosis, and foreign body reaction. According to the ISO score, Intercoat and Spraygel were considered as nonirritating to tissue. Adept, Seprafilm, and SupraSeal were assessed as mild-irritating materials. Interestingly, the most effective material in adhesion prevention revealed moderate inflammation accompanied by minor fibrosis. The degree of inflammation to barrier materials does not predict the efficacy in the prevention of adhesions. Histopathological investigations are crucial to improve our understanding of the cellular mechanisms during adhesion formation and elucidate the tissue response to material approaches used in adhesion prevention. This will lead to improved antiadhesive strategies and the development of functional barrier biomaterials.
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