Different effects of single protein vs. protein mixtures on magnesium degradation under cell culture conditions

Abstract

Bovine serum albumin (BSA) or fetal bovine serum (FBS), as the protein component, is usually added into solution to study the influence of proteins on Mg degradation. However, the specific character of proteins used and the interaction between organic molecules in FBS do not draw enough attention. This study investigated the influence of BSA, fibrinogen (Fib) and FBS on Mg degradation in Hanks’ balanced salt solution without (HBSS) or with calcium (HBSSCa) and Dulbecco's modified eagle medium Glutamax-I (DMEM). The results reveal that the effect of BSA, Fib and FBS on the degradation rate of Mg is time- and media-dependent, as a result of the overlap of protein adsorption, binding/chelating to ions and interaction between organic molecules. The binding/chelating of proteins and/or the possible effect of proteins on the kinetics of products formation lead to the formation of different degradation precipitates on Mg surface in HBSS. The interaction between proteins and Ca2+/PO43− accelerates the formation of Ca-P salts in HBSSCa and DMEM, thereby impeding the degradation of Mg. Moreover, the interplay between organic molecules and the specific character of proteins are highlighted by the cooperative (in media + FBS) or competitive (in DMEM + BSA + Fib) effect of proteins in the presence of more kinds of proteins and the different effect of BSA and Fib on the degradation of Mg. Therefore, the addition of proteins to testing medium is necessary for in vitro tests and DMEM + 10% FBS is recommended as the in vitro testing medium to present an in vivo-like degradation for Mg.