CONICET | Buscador de Institutos y Recursos Humanos

Fe-based biodegradable metallic materials (Fe-BMMs) have been proposed for cardiovascular applica-tions and are expected to disappear via corrosion after an appropriate period. However, in vivo studiesshowed that Fe ions release leads to accumulation of orange and brownish insoluble products at thebiomaterial/cell interface. As an additional consequence, sharp changes in pH may affect the biocompat-ibility of these materials. In the present work, the experimental protocols were designed with the aim ofevaluating the relative importance that these factors have on biocompatibility evaluation of BMMs. Mito-chondrial activity (MTT assay) and thiobarbituric acid reactive substances (TBARS) assay on mammaliancells, exposed to 1?5 mM of added Fe3+salt, were assessed and compared with results linked exclusivelyto pH effects. Soluble Fe concentration in culture medium and intracellular Fe content were also deter-mined. The results showed that: (i) mitochondrial activity was affected by pH changes over the entirerange of concentrations of added Fe3+assayed, (ii) at the highest added Fe3+concentrations (≥3 mM),precipitation was detected and the cells were able to incorporate the precipitate, that seems to be linkedto cell damage, (iii) the extent of precipitation depends on the Fe/protein concentration ratio; and (iv)lipid peroxidation products were detected over the entire range of concentrations of added Fe3+. Hence, anew approach opens in the biocompatibility evaluation of Fe-based BMMs, since the cytotoxicity wouldnot be solely a function of released (and soluble) ions but of the insoluble degradation product amountand the pH falling at the biomaterial/cell interface. The concentration of Fe-containing products at theinterface depends on diffusional conditions in a very complex way that should be carefully analyzed inthe future.