Metal release from various grades of stainless steel exposed to synthetic body fluids

Release rates of individual alloy constituents have been determined from seven grades of stainless steels exposed to two synthetic body fluids, used as surrogates for different areas of potential exposure in the lung: “Gamble’s solution”, (pH 7.4) that represents the interstitial fluid of the deep lung, and artificial lysosomal fluid (ALF) that represents the more acidic (pH 4.5-5) milieu of particles following their phagocytosis by macrophages. Total metal release rates from all grades of stainless steel investigated were low (<5 μg cm⁻² week⁻¹). The more acidic environment of ALF resulted in significantly higher total metal release rates (0.3-4.6 μg cm⁻² week⁻¹) compared to Gamble’s solution (<0.1 μg cm⁻² week⁻¹).