Application of stripping voltammetry and microelectrodes in vitro biocompatibility and in vivo toxicity tests of AISI 316L corrosion products

Adsorptive stripping voltammetric procedures, using mercury film microelect rodes, were optimised and applied to quantify total iron, chromium and nick el in samples of osteoblast-like cells culture medium and mice organs (live r, kidney and spleen) obtained from, respectively, in vitro and in vivo 316 L stainless steel corrosion products biocompatibility and toxicity studies. The methods were based on the pre-concentration of the iron-catechol compl ex by adsorption at the potential of -1.80 V (vs.Ag/AgCl), of the chromium- diethylenetriaminepentaacetic acid complex at -1.00 V or -1.15 V (vs. Ag/Ag Cl) and of the nickel-dimethylglyoxime complex at -0.70 V (vs. Ag/AgCl). Th e detection limits achieved for each metal ion (i) in the culture medium we re 1.93x10(-6) mol/L Fe, 2.80x10(-10) mol/L Cr and 7.70x10(-9) mol/L Ni for a collection time of 30 s, 40 s and 10 s, respectively, and (ii) in the mi ce organ solutions were 1.37x10(-8) mol/L Fe, 1.54x10(-8) mol/L Ct and 1.58 x10(-9) mol/L Ni for an adsorption time of 25 s, 25 s and 15 s, respectivel y. The accuracy of the proposed procedures was verified by comparison of th e results obtained by adsorptive stripping voltammetry with those attained by atomic absorption spectrometry for the same set of samples and good agre ement was found. The in vitro study showed that stainless steel corrosion p roducts affect the expression of the osteogenic phenotype. The in vivo mice model, used to investigate the systemic effects provoked by the corrosion products per se, indicated that Fe, Cr and Ni are partially accumulated in the organs studied and that Ni induced the more significant morphological a lterations.