[en] Magnesium and its alloys are currently considered to be a promising metallic biomaterial. The increasing interest in magnesium alloys is due to their biocompatibility, biodegradability and in particular to their mechanical properties which can be matched more closely to those of bone than the mechanical properties of other competitor metallic biomaterials, such as stainless steel and titanium. Due to these characteristics, magnesium alloys represent a promising material to be used for biodegradable implants. Magnesium is also gaining interest in regenerative medicine, especially for the fabrication of scaffolds that support tissue formation. For their application in regenerative medicine, the scaffolds have to present a porous open-cell structure. However, despite the mentioned features, magnesium alloys must overcome their poor corrosion resistance. The main purpose of the present research work was to develop porous magnesium scaffolds for their use in tissue engineering. First, in order to identify the problems of magnesium as biomaterial, cell cultures on magnesium alloys were carried out as a starting point. In addition to the identified problems of magnesium alloys in regenerative medicine by other authors (hydrogen bubbles, pH increase), it was also detected that adhered crystals on the surface can stop the tissue growth, due to the crystals, samples were only partially covered by a cell layer. This was the reason why the crystal deposition and the corrosion behaviour in PBS solution of magnesium alloys as well as the influence of fluoride treatment on their corrosion and cell viability were analysed. Taking into account these results, novel Mg-Zn alloys with a chemical composition designed to increase their cell viability were developed. It was shown that an acceptable cell viability was achieved with the novel Mg-Zn alloys compared to Ti-6Al-4V. Furthermore, the fluoride treatment decreased the corrosion rate and increased the cell viability in all the analysed alloys. Finally, replication casting process was analysed for the manufacturing of magnesium scaffolds. The optimal process parameters for several alloys were analysed taking into account the porosity and the mechanical properties of the magnesium foams. As a final result, highly porous scaffolds manufactured with Mg-Zn alloys and coated with MgF2 for reducing their corrosion rate have been developed. Their low hydrogen evolution, measured during the present work, makes them a potential application element in tissue engineering.

[eu] Gaur egun magnesioa eta bere aleazioak metalezko biomaterialen artean oso interesgarriak bihurtu dira. Interes hau handituz doa bere biobateragarritasunari, biodegradazioari eta batez ere, bere propietate mekanikoei esker. Ohizko biomaterial metalikoekin (titanioa eta altzairu herdoilgaitzak) alderatuz, magnesio aleazioen propietate mekanikoak hezurrarekiko antzekotasun handiagoa dute. Ezaugarri guzti hauek etorkizun handiko materiala bihurtzen dute inplante degradagarrien arloan. Birsorkuntza-medikuntzan ere magnesioren interesa handitzen doa, ehun berria sortzeko erabiltzen diren zelula-aldamioen fabrikazio esparruan hain zuzen ere. Zelula-aldamioek hiru dimentsioko egitura porotsua eduki behar dute eta bere poroak elkar lotuta egon behar dira. Birsorkuntza-medikuntzaren sektorean magnesio aleazioak etorkizun handiko materialak badira ere, korrosioarekiko duten erresistentzia apala da hauen erabilpena oztopatzen duena. Ikerkuntza lan honen helburu nagusia birsorkuntza-medikuntzan aplikatzeko magnesiozko zelula-aldamioen garapena izan zen. Abiapuntu bezala zelulakultiboak burutu ziren biomaterial gisa erabiltzean magnesioak dituen arazoak zeintzuk diren jakiteko. Literaturan aurkitu ziren arazoez gain (hidrogeno burbuilen sorketa, pH igoera), ehunaren haztea gelditzen zuen kristalen atxikidura handi bat antzeman zen materialaren gainazalean. Kristal atxikidura hori dela eta, zelulek ez zuten lagin osoa estali. Horregatik, magnesio aleazioen korrosioa, zelula-bideragarritasuna, kristalen sorkuntza eta fluoruro tratamenduen eragina magnesio aleazioetan aztertu ziren. Emaitza hauek kontuan hartuta, Mg-Zn aleazio berriak garatu ziren zelula-bideragarritasuna handitzeko. Aleazio hauek zelula-bideragarritasun egokia erakutsi zuten Ti-6Al-4V aleazioarekin konparatuta. Gainera, fluoruro tratamenduak korrosioarekiko erresistentzia eta zelula-bideragarritasuna handitu zituela antzeman zen aleazio guztietan. Azkenik, magnesiozko zelula-aldamioak fabrikatzeko galdaketa prozesua aztertu zen. Fabrikazio-parametroak aztertu eta optimizatu ziren fabrikazioa, porositatea eta aparren propietate mekanikoak kontuan hartuta. Garatutako zelula-aldamioek fluoruro tratamenduarekin garatu ziren. Zelulaaldamio hauek ez zuten hidrogeno sorkuntza handia izan. Hau horrela izanik, garatutako zelula-aldamioak hautagai interesgarri bihurtzen dira birsorkuntza-medikuntzan erabiliak izateko.