Abstract

Filtration of a suspension of calcium carbonate (CaC0(3)) or other inorganic solutions are often part of the methodology for recovering crystals during biomimetic mineralization experiments performed by various procedures. However, the use of cellulose filter membranes (FM) may cause a problem in in vitro crystallization experiments, because constituents released from the filters into the filtrates can alter the morphology of CaC0(3) crystals. Therefore, it is possible to misinterpret data obtained when the effect of specific additives tested in the investigation of biomineralization mechanisms. Herein, we present essential information to avoid such misinterpretations of data obtained from mineralization experiments. CaC0(3) was precipitated at room temperature by the gas diffusion method in the presence of FM as support and particularly as filtrates of calcium chloride (CaCl2) obtained from various commercial FM. The occurrence or absence of morphological modifications of the calcite and vaterite crystals obtained with different FM correlates well with the different elemental compositions of the solutions where crystals are grown because of the constituents released from the filters into the filtrate. X-ray photoelectron spectroscopy (XPS) data indicate significant differences in the filter elemental composition. We assume that the observed chronological changes in CaC0(3) crystal modification could be due to incorporation into the calcite lattice of constituents released from the FM, most likely monomers, oligomers, or short-chain polymers.