| 1. |
- Karhula, Sakari, et al.
(författare)
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Effects of articular cartilage constituents on phosphotungstic acid enhanced micro-computed tomography
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Contrast-enhanced micro-computed tomography (CEμCT) with phosphotungstic acid (PTA) has shown potential for detecting collagen distribution of articular cartilage. However, the selectivity of the PTA staining to articular cartilage constituents remains to be elucidated. The aim of this study was to investigate the dependence of PTA for the collagen content in bovine articular cartilage. Adjacent bovine articular cartilage samples were treated with chondroitinase ABC and collagenase to degrade the proteoglycan and the collagen constituents in articular cartilage, respectively. Enzymatically degraded samples were compared to the untreated samples using CEμCT and reference methods, such as Fourier-transform infrared imaging. Decrease in the X-ray attenuation of PTA in articular cartilage and collagen content was observed in cartilage depth of 0-13% and deeper in tissue after collagen degradation. Increase in the X-ray attenuation of PTA was observed in the cartilage depth of 13-39% after proteoglycan degradation. The X-ray attenuation of PTA-labelled articular cartilage in CEμCT is associated mainly with collagen content but the proteoglycans have a minor effect on the X-ray attenuation of the PTA-labelled articular cartilage. In conclusion, the PTA labeling provides a feasible CEμCT method for 3D characterization of articular cartilage.
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| 2. |
- Nissilä, Tuukka, et al.
(författare)
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Cellulose nanofiber aerogels impregnated with bio-based epoxy using vacuum infusion : Structure, orientation and mechanical properties
- 2018
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Ingår i: Composites Science And Technology. - : Elsevier. - 0266-3538 .- 1879-1050. ; 155, s. 64-71
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanofiber aerogels were used as preforms that were impregnated with a bio-epoxy resin via a widely used vacuum infusion process. The simple and straightforward nanocomposite processing approach resulted in an almost 70% improvement in the storage modulus of the polymer with only an 11.7 wt% cellulose nanofiber content. The nanofibers were well dispersed in the polymer matrix and the fiber structures were anisotropically aligned. The impregnation time of the aerogels was also significantly lower than that of the more commonly used nanopapers. It was thus shown that environmentally friendly and mechanically robust nanocomposites could be produced by impregnating cellulose nanofiber aerogels with a thermosetting resin using a processing approach that has potential to be scaled up for commercial use.
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| 3. |
- Prittinen, Juha, 1989-, et al.
(författare)
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Effect of centrifugal force on the development of articular neocartilage with bovine primary chondrocytes
- 2019
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Ingår i: Cell and Tissue Research. - New York : Springer. - 0302-766X .- 1432-0878. ; 375:3, s. 629-639
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Tidskriftsartikel (refereegranskat)abstract
- A lot has been invested into understanding how to assemble cartilage tissue in vitro and various designs have been developed to manufacture cartilage tissue with native-like biological properties. So far, no satisfactory design has been presented. Bovine primary chondrocytes are used to self-assemble scaffold-free constructs to investigate whether mechanical loading by centrifugal force would be useful in manufacturing cartilage tissue in vitro. Six million chondrocytes were laid on top of defatted bone disks placed inside an agarose well in 50-ml culture tubes. The constructs were centrifuged once or three times per day for 15 min at a centrifugal force of 771×g for up to 4 weeks. Control samples were cultured under the same conditions without exposure to centrifugation. The samples were analysed by (immuno)histochemistry, Fourier transform infrared imaging, micro-computed tomography, biochemical and gene expression analyses. Biomechanical testing was also performed. The centrifuged tissues had a more even surface covering a larger area of the bone disk. Fourier transform infrared imaging analysis indicated a higher concentration of collagen in the top and bottom edges in some of the centrifuged samples. Glycosaminoglycan contents increased along the culture, while collagen content remained at a rather constant level. Aggrecan and procollagen α1(II) gene expression levels had no significant differences, while procollagen α2(I) levels were increased significantly. Biomechanical analyses did not reveal remarkable changes. The centrifugation regimes lead to more uniform tissue constructs, whereas improved biological properties of the native tissue could not be obtained by centrifugation.
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| 4. |
- Prittinen, Juha, 1989-, et al.
(författare)
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Effect of gravitational force on the development of articular neocartilage with bovine primary chondrocytes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A lot of effort has been invested into understanding how to assemble cartilage tissue in vitro. Various scaffold types have been used in order to manufacture cartilage tissue with native-like biological properties, while cell-based self-assembly of cartilage without a scaffold material is another strategy utilized. Mechanical forces have also been exploited in the manufacturing process. In this study, we used bovine primary chondrocytes to self-assemble a scaffold-free constructs to investigate whether mechanical loading by gravitational force would be useful in manufacturing cartilage tissue in vitro. Six million chondrocytes were laid on top of defatted bone disks placed inside agarose well in 50 ml culture tubes. The constructs were centrifuged once or three times a day for 15 min at gravitational force of 770 x g for one, two and four weeks. Control samples were cultured under the same conditions without exposure to centrifugation. The samples were analysed by (immuno)histochemistry, Fourier transform infrared imaging, micro-computed tomography, biochemical and gene expression analyses. Biomechanical testing was also performed. Macroscopically, the centrifuged tissues had a more even surface covering a larger area of the bone disk. Fourier transform infrared imaging analysis indicated higher concentration of collagen in the top and bottom edges of the centrifuged samples. Glycosaminoglycan contents increased along the culture, while collagen content appeared to remain at a rather constant level. Aggrecan and procollagen α1(II) gene expression levels had no significant differences, while procollagen α2(I) levels were increased significantly. Biomechanical analyses did not reveal remarkable changes. In conclusion, both of the centrifugation regimes lead to a more uniform tissue constructs, while the biological properties of the native tissue could not be obtained.
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