Crystalline-magnetism action in biomimetic mineralization of calcium carbonate

The influence of minor environmental factors, such as the geomagnetic field, on the biomineralization of nacres, is often ignored but a great deal of research has confirmed its important role in the normal mineralization of calcium carbonate. Although the geomagnetic field is weak, its cumulative effects need to be considered given that the biomineralization process can take years. Accordingly, the authors of this paper have investigated the effects of weak magnetic fields (25 Gs or 50 Gs) on calcium carbonate mineralization and analyzed the mechanism involved. The results show that even a weak magnetic field conduces to the formation of vaterite or aragonite, in the induction order of precursor → vaterite → aragonite. The stronger the magnetic field and the longer the time, the more obvious the induction effect. The effect of a magnetic field is strongest in the aging stage and weakest in the solution stage. Inductions by egg-white protein and by a magnetic field inhibit each other, but they both restrict particle growth. These findings highlight the importance of minor environmental factors for biomineralization and can serve as a reference for biomimetic preparation of a CaCO3 nacre-like structure and for anti-scale technology for circulating cooling water.