| 1. |
- López, Alejandro, 1983-, et al.
(author)
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Low-modulus PMMA bone cement modified with castor oil
- 2011
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In: Bio-medical materials and engineering. - : IOS Press. - 0959-2989 .- 1878-3619. ; 21:5-6, s. 323-332
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Journal article (peer-reviewed)abstract
- Some of the current clinical and biomechanical data suggest that vertebroplasty causes the development of adjacent vertebral fractures shortly after augmentation. These findings have been attributed to high injection volumes as well as high Young’s moduli of PMMA bone cements compared to that of the osteoporotic cancellous bone. The aim of this study was to evaluate the use of castor oil as a plasticizer for PMMA bone cements. The Young’s modulus, yield strength, maximum polymerization temperature, doughing time, setting time and the complex viscosity curves during curing, were determined. The cytotoxicity of the materials extracts was assessed on cells of an osteoblast-like cell line. The addition of up to 12 wt% castor oil decreased yield strength from 88 to 15 MPa, Young’s modulus from 1500 to 446 MPa and maximum polymerization temperature from 41.3 to 25.6◦C, without affecting the setting time. However, castor oil seemed to interfere with the polymerization reaction, giving a negative effect on cell viability in a worst-case scenario.
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| 2. |
- Matsuoka, Atsuko, et al.
(author)
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Development of an in vitro screening method for safety evaluation of nanomaterials
- 2009
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In: Bio-medical materials and engineering. - 0959-2989 .- 1878-3619. ; 19:1, s. 19-27
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Journal article (peer-reviewed)abstract
- To evaluate the role of particle size in cytotoxicity tests of nanomaterials (NMs), we exposed Chinese hamster cells to polystyrene (PS) spheres with defined diameters ranging from 0.1 to 9.2 mu m. We found that the 4.45-mu m PS particles were most cytotoxic while sizes 0.1 and 0.2 mu m showed no cytotoxicity up to 1000 mu g/ml. In the chromosome aberration test, the 4.45-mu m PS particles induced polyploidy in amass concentration-dependent manner in 24- and 48-h treatments. The 5.26-mu m PS particles induced polyploidy only at 1000 mu g/ml for 48 h. Next, we performed the cytotoxicity test with as-grown single walled carbon nanohorns (NHas). These were suspended in DMSO and then transferred into the culture medium followed by sonication. Six suspensions differently sonicated showed the same apparent toxicity, although the total particle size distributions differed. However, the sizes of NHas particles predicted to be most toxic from the experiments with PS particles, i.e. 1.01-4.47 mu m constituted 40-60% of all particles in all six suspensions. The results suggest that the cytotoxicity of NMs in suspension depends on specific sizes of aggregates and therefore suspensions should be checked with regard to particle size distributions in assays of toxic effects. The uptake of particles into cells was confirmed by confocal microscopy.
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| 3. |
- Nordberg, Axel, et al.
(author)
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Vertebral fractures fixation with composite patch fibre reinforced adhesives
- 2007
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In: Bio-medical materials and engineering. - 0959-2989 .- 1878-3619. ; 17:5, s. 299-308
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Journal article (peer-reviewed)abstract
- Purpose: The aim is to investigate fixation of cervical vertebral fractures by patching it with a composite laminate of adhesive and fibres, in comparison with use of only adhesives. Material and methods: The composite fixation was tested on bonded roe deer vertebrae. 25 specimens were sawed in two halves, creating a generic fracture, and thereafter bonded. The adhesives used were a dental system, Scotchbond XT, and a cyanoacrylate, M-bond 200. The fibres used were unidirectional carbon fibres and randomly distributed E-glass fibres. The composites were applied as a 7 mm wide patch circumferential along the induced fracture. Reference specimens for comparison were also made. The ultimate tensile strength was tested in an Instron 5567. The failure site was examined with a microscope. Strain vectors were tracked using Digital Speckle Analysis. Results: Scotchbond XT + E-glass fibres gave best results, with a tensile strength of 3.5 N/mm circumferential length (24.3% of reference). All composites had lower stiffness than cortical bone. The dental adhesive fibre composites gave better results than the cyanoacrylate fibre composites. In all cases fibre reinforced adhesive composite gave better results than adhesive without fibre reinforcement. Conclusion: Fibre-adhesive composite is a promising technique for fixating cervical vertebral fractures.
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| 4. |
- Pulkkinen, Hertta, et al.
(author)
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Cellulose sponge as a scaffold for cartilage tissue engineering.
- 2006
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In: Bio-medical materials and engineering. - : IOS Press. - 0959-2989 .- 1878-3619. ; 16:4 Suppl, s. S29-S35
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Journal article (peer-reviewed)abstract
- One goal of functional tissue engineering is to manufacture scaffolds infiltrated with chondrocytes which are suitable for transplantation into the lesion areas of articular cartilage. Various research strategies are used to fabricate cartilage transplants which would have the correct phenotype, contain enough extracellular matrix components, and have structural and biomechanical properties equivalent to normal articular cartilage. We have investigated the suitability of viscose cellulose sponges as a scaffold for cartilage tissue engineering. The sponges were tested alone, or with recombinant human type II collagen cross-linked inside the material. Scanning electron microscopy and confocal microscopy were used to study the structure of the scaffold during four weeks of cultivation. Cellulose and cellulose/recombinant type II collagen sponges were biocompatible for at least four weeks in cultivation, and gradual filling of the scaffold was observed. However, the constructs remained soft during the observation period, and were devoid of extracellular matrix composition typical for normal articular cartilage.
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| 5. |
- Salvo, P., et al.
(author)
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Fabrication and functionalization of PCB gold electrodes suitable for DNA-based electrochemical sensing
- 2014
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In: Bio-medical materials and engineering. - 0959-2989 .- 1878-3619. ; 24:4, s. 1705-1714
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Journal article (peer-reviewed)abstract
- The request of high specificity and selectivity sensors suitable for mass production is a constant demand in medical research. For applications in point-of-care diagnostics and therapy, there is a high demand for low cost and rapid sensing platforms. This paper describes the fabrication and functionalization of gold electrodes arrays for the detection of deoxyribonucleic acid (DNA) in printed circuit board (PCB) technology. The process can be implemented to produce efficiently a large number of biosensors. We report an electrolytic plating procedure to fabricate low-density gold microarrays on PCB suitable for electrochemical DNA detection in research fields such as cancer diagnostics or pharmacogenetics, where biosensors are usually targeted to detect a small number of genes. PCB technology allows producing high precision, fast and low cost microelectrodes. The surface of the microarray is functionalized with self-assembled monolayers of mercaptoundodecanoic acid or thiolated DNA. The PCB microarray is tested by cyclic voltammetry in presence of 5 mM of the redox probe K3Fe(CN6) in 0.1 M KCl. The voltammograms prove the correct immobilization of both the alkanethiol systems. The sensor is tested for detecting relevant markers for breast cancer. Results for 5 nM of the target TACSTD1 against the complementary TACSTD1 and non-complementary GRP, MYC, SCGB2A1, SCGB2A2, TOP2A probes show a remarkable detection limit of 0.05 nM and a high specificity.
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| 6. |
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| 7. |
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| 8. |
- Sundberg, Johan, 1982, et al.
(author)
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Biosynthesis and in vitro evaluation of macroporous mineralized bacterial nanocellulose scaffolds for bone tissue engineering
- 2015
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In: Bio-Medical Materials and Engineering. - : IOS Press. - 0959-2989. ; 25:1, s. 39-52
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Journal article (peer-reviewed)abstract
- Macroporous bacterial nanocellulose (BNC) scaffolds with calcium phosphate coated surfaces is a candidate for future bone tissue engineering applications. The mineralization of the macroporous BNC scaffolds was achieved by a biomimetic process, resulting in an environment resembling native bone tissues' mineralized extra cellular matrix both topographically and chemically. The deposited crystals were analyzed with electron spectroscopy for chemical analysis (ESCA), energy-dispersive X-ray spectroscopy (EDX) and X-ray crystallography (XRD). MSCs were cultured in osteogeneic medium for 21 days on the scaffolds. The results of this study show that macroporous BNC can be mineralized with hydroxyapatite and that MSCs retain their ability to proliferate and differentiate towards an osteoblastic phenotype within the mineralized BNC, showing the promise of this material in bone tissue engineering applications.
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| 9. |
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