| 1. |
- Augustine, Robin
(författare)
-
Biocompatibility study of hydroxyapatite-chitosan composite for medical applications at microwave frequencies
- 2008
-
Ingår i: Microwave and optical technology letters (Print). - 0895-2477 .- 1098-2760. ; 50:11, s. 2931-2934
-
Tidskriftsartikel (refereegranskat)abstract
- Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and chitosan (poly [(β-1-4) d-glucosamine]) biopolymer show good biocompatibility in vivo. They have biological origin and show excellent interactions with microwave. Microwave study of HAp made using different drying techniques and their composites with chitosan in the ISM band is presented. Pastes are made using HAp and chitosan with different ratios of mixing. The dielectric properties of this composites match with that of human fat, collagen tissues. Some of the compositions exhibit dielectric property close to that of natural bone. This makes them more biocompatible and better substitutes for natural bone. Thus composite bioceramics can be considered as phantom model constituents for imaging purposes.
|
|
| 2. |
- Augustine, Robin, 1982-
(författare)
-
Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film
- 2009
-
Ingår i: Microwave and Optical Technology Letters. ; 51:5
-
Tidskriftsartikel (refereegranskat)abstract
- Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film
|
|
| 3. |
- Augustine, Robin, 1982-
(författare)
-
Biocompatibility study of beta tricalcium phosphate bioceramics and chitosan biopolymer and their use as phantoms for medical imaging applications
- 2009
-
Ingår i: Microwave and Optical Technology Letters. ; 51:12
-
Tidskriftsartikel (refereegranskat)abstract
- Beta tricalcium phosphate (b-TCP) bioceramics and chitosan biopolymers are used as biomedical implants because of their better biocompatibility and good bioresorption characteristics. As they are biomaterials, they have good interactions with microwave frequencies. b-TCP and chitosan powder, films, pellets, and gel are prepared and studied at the S-band microwave frequencies. Dielectric parameters such as dielectric constant, dielectric loss, conductivity, and S-parameters are evaluated. Dielectric parameters of different forms of b-TCP and chitosan show resemblance with that of human tissues. Hence, these materials can also be considered as potential phantoms for specific absorption rate measurements as well as in microwave imaging applications. V
|
|
| 4. |
- Brohede, Ulrika, et al.
(författare)
-
Multifunctional implant coatings providing possibilities for fast antibiotics loading with subsequent slow release
- 2009
-
Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 20:9, s. 1859-1867
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility to fast-load biomimetic hydroxyapatite coatings on surgical implant with the antibiotics Amoxicillin, Gentamicin sulfate, Tobramycin and Cephalothin has been investigated in order to develop a multifunctional implant device offering sustained local anti-bacterial treatment and giving the surgeon the possibility to choose which antibiotics to incorporate in the implant at the site of surgery. Physical vapor deposition was used to coat titanium surfaces with an adhesion enhancing gradient layer of titanium oxide having an amorphous oxygen poor composition at the interface and a crystalline bioactive anatase TiO2 composition at the surface. Hydroxyapatite (HA) was biomimetically grown on the bioactive TiO2 to serve as a combined bone in-growth promoter and drug delivery vehicle. The coating was characterized using scanning and transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The antibiotics were loaded into the HA coatings via soaking and the subsequent release and antibacterial effect were analyzed using UV spectroscopy and examination of inhibition zones in a Staphylococcus aureus containing agar. It was found that a short drug loading time of 15 min ensured antibacterial effects after 24 h for all antibiotics under study. It was further found that the release processes of Cephalothin and Amoxicillin consisted of an initial rapid drug release that varied unpredictably in amount followed by a reproducible and sustained release process with a release rate independent of the drug loading times under study. Thus, implants that have been fast-loaded with drugs could be stored for ~10 min in a simulated body fluid after loading to ensure reproducibility in the subsequent release process. Calculated release rates and measurements of drug amounts remaining in the samples after 22 h of release indicated that a therapeutically relevant dose could be achieved close to the implant surface for about 2 days. Concluding, the present study provides an outline for the development of a fast-loading slow-release surgical implant kit where the implant and the drug are separated when delivered to the surgeon, thus constituting a flexible solution for the surgeon by offering the choice of quick addition of antibiotics to the implant coating based on the patient need.
|
|
| 5. |
- Cieślik, M., et al.
(författare)
-
Metal release and formation of surface precipitate at stainless steel grade 316 and Hanks solution interface : Inflammatory response and surface finishing effects
- 2009
-
Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 51:5, s. 1157-1162
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of surface finishing (polishing and passivation) on the release of Cr, Fe, Ni from the stainless steel 316 implant materials to Hanks solution with or without H2O2 (simulating a body inflammatory response) was investigated. The surfaces were characterized by means of SEM EDXS, XPS and Kelvin Probe measurements before and after exposure to the synthetic body fluids. The total metal ions release rates are more than 10 times higher in the presence of H2O2, independently of the surface finishing. In the absence of H2O2, formation of a surface layer consisting mainly of Ca3(PO4)2 was observed, most likely it was responsible for the observed decrease of the release rates. © 2009 Elsevier Ltd. All rights reserved.
|
|
| 6. |
- Fredriksson, Camilla, et al.
(författare)
-
Tissue Response to Subcutaneously Implanted Recombinant Spider Silk : An in Vivo Study
- 2009
-
Ingår i: Materials. - Basel, Switzerland : MDPI AG. - 1996-1944. ; 2:4, s. 1908-1922
-
Tidskriftsartikel (refereegranskat)abstract
- Spider silk is an interesting biomaterial for medical applications. Recently, a method for production of recombinant spider silk protein (4RepCT) that forms macroscopic fibres in physiological solution was developed. Herein, 4RepCT and MersilkTM (control) fibres were implanted subcutaneously in rats for seven days, without any negative systemic or local reactions. The tissue response, characterised by infiltration of macrophages and multinucleated cells, was similar with both fibres, while only the 4RepCT-fibres supported ingrowth of fibroblasts and newly formed capillaries. This in vivo study indicates that 4RepCT-fibres are well tolerated and could be used for medical applications, e.g., tissue engineering.
|
|
| 7. |
- Jegou Saint-Jean, Simon, et al.
(författare)
-
Study of the reactivity and in vitro bioactivity of Sr-substituted alpha-TCP cements
- 2005
-
Ingår i: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 1573-4838 .- 0957-4530. ; 16:11, s. 993-1001
-
Tidskriftsartikel (refereegranskat)abstract
- In this study the effect of strontium substitution on the hydrolysis of alpha-tricalcium phosphate (alpha-TCP) toward the formation of calcium deficient hydroxyapatite (CDHA) was investigated. For that purpose substituted alpha-TCP powders with 1, 5 and 10 mol% Sr substitution for Ca were synthesized by reacting at 1500 degrees C stoichiometric amounts of CaCO3, SrCO3, and Ca2P2O7, followed by rapid quenching in air. XRD analysis of the powders revealed the presence of alpha-TCP (traces of beta-TCP) with enlarged unit cell volume at increased Sr contents, indicating the incorporation of Sr in the crystal structure. Strontium was also incorporated in the apatite phase as revealed by XRD analysis of the set cements. The hydrolysis of milled alpha-SrTCP powders and a pure alpha-TCP (control) was monitored by isothermal calorimetry and the compressive strength of set cements was tested. The results showed a decrease in the reactivity with increasing Sr content and similar final mechanical strength within the Sr series, though lower than the control. The in vitro bioactivity of the set cements after soaking in simulated body fluid for 4 weeks was also tested. The formation of a bone-like apatite layer on the surface of the set cements indicated a potential in vivo bioactivity. (C) 2005 Springer Science + Business Media, Inc.
|
|
| 8. |
- Johansson, Fredrik, et al.
(författare)
-
Nanomodified surfaces and guidance of nerve cell processes
- 2008
-
Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567 .- 1071-1023. ; 26:6, s. 2558-2561
-
Konferensbidrag (refereegranskat)abstract
- Axonal growth and guidance were studied on different micro- and nanostructured surfaces. Nanoimprinted grooves in a polymer, epitaxial III/V nanowires, porous silicon patterns, and chemically altered surfaces were all shown to induce axonal guidance. Neurons were also found to be able to attach and grow on gallium phosphide nanowires without compromising cell survival. The results are important for the construction of a new generation of neuroelectrical interfaces, including high spatial resolution electrodes. The advantages of the different nanostructured surfaces are discussed.
|
|
| 9. |
- Kjellson, Fred, et al.
(författare)
-
Effect of iodixanol particle size on the mechanical properties of a PMMA based bone cement.
- 2007
-
Ingår i: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 1573-4838 .- 0957-4530. ; 18, s. 1043-1051
-
Tidskriftsartikel (refereegranskat)abstract
- Iodixanol (IDX) is a water soluble opacifier widely used in radiographical examinations of blood vessels and neural tissue, and it has been suggested as a potential contrast media in acrylic bone cement. The effect of the iodixanol particle size on the polymerisation process of the bone cement, the molecular weight, and the quasi-static mechanical properties have been investigated in this article. The investigation was performed using radiolucent Palacos powder mixed with 8 wt% of iodixanol with particle sizes ranging from 3 to 20 mu m MMD, compared with commercial Palacos R (15 wt% ZrO2) as control. Tensile, compressive and flexural tests showed that smaller particles (groups with 3, 4, and 5 mu m particles) resulted in significantly lower mechanical properties than the larger particles (groups with 15, 16, and 20 mu m particles). There was no difference in molecular weight between the groups. The thermographical investigation showed that the IDX cements exhibit substantially lower maximum temperatures than Palacos R, with the 4 mu m IDX group having the lowest maximum temperature. The isothermal and the constant rate differential scanning calorimetry (DSC) did not show any difference in polymerisation heat (Delta H) or glass transition temperature (T-g) between radiolucent cement, or cement containing either IDX, or ZrO2. The findings show that the particle size for a bone cement containing iodixanol should be above 8 mu m MMD.
|
|
| 10. |
- Lund, Katarina, 1982-, et al.
(författare)
-
A User-Centered Evaluation Study of a Mobile Arm Support
- 2009
-
Ingår i: 2009 IEEE 11th International Conference on Rehabilitation Robotics. - : IEEE. - 9781424437887 ; , s. 678-683
-
Konferensbidrag (refereegranskat)abstract
- Evaluating Assistive Technology (AT) from a user point of view is important if we want to assess reasons for non-use and to find out how to better design products that will fit the individual needs of its end-user. This article presents a user centered evaluation study of an Assistive Device (AD), in particular the Armon mobile arm support. Seven users were interviewed using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) and Individually Prioritized Problem Assessment (IPPA). In all cases the AD had a positive effect on the ability of the users to perform important tasks in their every day lives independently. The users also reported an overall high level of content with the device whereas there were some remarks of discontent regarding the service and fitting process.
|
|
