Cytotoxicity of corrosion products of degradable Fe-based stents: Relevance of pH and insoluble products

FAGALI, N; GRILLO, C; PUNTARULO, S; FERNÁNDEZ LORENZO DE MELE, M

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 128 p. 480 - 488

0927-7765

Biodegradable metallic materials (BMM) have been proposed for specific objectives such as cardiovascular and orthopedic applications and are expected to disappear via corrosion after an appropriate period to ensure a complete healing tissue process. However, the high rate of the ions release leads to accumulation of degradation products in the biomaterial surroundings, as well as sharp changes in pH, that can affect the biocompatibility of these materials. In the present work, the assays protocols were designed to understand the relative importance that these factors have on biocompatibility evaluation of BMM. Mitochondrial activity (MTT assay) and thiobarbituric acid reactive substances (TBARS) assay on CHO-K1 cells, exposed to 1-5 mM of added Fe3+ salt, were assessed and compared to results due to pH effects (8.4-5.6). Soluble Fe concentration in culture medium and intracellular Fe content were also determined. The results showed that: i) mitochondrial activity was affected by pH changes in all the concentration range 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 linked to cell damage, and iii) lipid peroxidation products were detected in all the concentration range of added Fe3+. The TBARS production seems to be related to intracellular Fe concentration. Otherwise, a new point of view opens in the biocompatibility evaluation of Fe-based BMM, since the cytotoxicity would not be a function of released (and soluble) ions but of the degradation product amount and the pH falling on the interface biomaterial/cell.