You are here: MEDICA Portal. MEDICA Magazine. Archive.
Researchers show that the ageing
and cracking of protheses could be
avoided; © Hemera
Current body protheses do not last more than ten to 15 years. After this time, the operation has to be repeated in order to change prothesis. Researchers have now found a way of producing a prosthesis that could last more than 150 years.
Changing prosthesis after a couple of years is usually problematic as, in general, it is elderly people that use the procedure. Researcher Nere Garmendia, based in the Basque city of Donostia-San Sebastián, has just published a thesis which may well mean the first step to solving this problem. According to Garmendia, using a ceramic material called zirconia, carbon nanotubes and nanoparticles of zirconia, a long-lasting prothesis can be produced.
With her thesis, Garmendia wished to show that the ageing and cracking of protheses could be avoided. To begin with, carbon nanotubes were added to the zirconia matrix – a technique that greatly strengthens its resistance. With this composite material as a base research was initiated.
Garmendia explained in her thesis that working at a nanometric scale is precisely the key to achieving long-lasting protheses. In a prior experiment with micrometric zirconia it was concluded that this material would end up considerably aged after twelve years.
Nevertheless, as has been pointed out, apart from the zirconia matrix, adding carbon nanotubes and the nanoparticles of zirconia coating them, the material will not age – even after 150 years. With the nanotubes coated, Garmendia investigated the capacity for the displacement and dispersion of the composite obtained from the previous process, and also looked for its suitable point of density. Based on this and aided by plaster, she achieved the first compact pieces.
Subsequently, Garmendia specified the number of coated nanotubes each piece had to have in order to achieve the optimum density at the end of the process. According to the researcher, adding zirconia nanoparticles to the nanotubes facilitates the dispersion of the material and reduces its viscosity, apart from helping to increase its density for the last stage: the synterisation stage.
Synterisation is a process, used particularly in ceramics, in order to transform the material from powder to a compact solid. Not just any quantity is useful to achieve this maximum possible density and, thus, before synterisation, it has to be decided how many nanotubes are to be introduced and, of course, synterisation has to be subsequently carried out correctly. Finally, the material has to be synterised in argon for one hour at 1,300 degrees; not more nor less.
MEDICA.de; Source: Elhuyar Fundazioa