IN-VITRO BIOMINERALIZATION BY OSTEOBLAST-LIKE CELLS - II - CHARACTERIZATION OF CELLULAR CULTURE SUPERNATANTS

The quantification of total calcium, phosphorus, iron, chromium and ni ckel in cell culture medium by electrochemical or spectroscopic means may require digestion of samples. Nevertheless, when pH adjustment is performed for values higher than about 6.5, the formation of two phase s occurs: a white precipitate and a clear solution. Analysing both pha ses using microelectrodes, atomic absorption spectrometry (AAS), diffu se reflectance infrared Fourier transform (DRIFT) spectroscopy, X-ray dispersive (XRD) analysis, scanning electron microscopy (SEM) and ener gy dispersive spectroscopic (EDS) analysis, it was observed that iron, chromium and nickel are not co-precipitating with the white solid pha se. If quantification of calcium, phosphorus and magnesium is intended , a ten-fold dilution at least, must be performed to avoid most of the se elements going into the precipitate. This knowledge is crucial if a mineralization study is going to be made. (C) 1998 Elsevier Science L td. All rights reserved.