Crystallization of Calcium Carbonate Vaterite Associated with Liquid Crystal in Embryonic Yolk Sacs

Calcium carbonate is often used as an efficient antacid that absorbs and neutralizes stomach acid while providing calcium for healthy bones. Taking advantage of the lack of adverse side effects of calcium, new drug delivery systems consisting of drug-supported spherical microparticles are being developed. We have reported in our previous studies that a natural process producing calcium carbonate microparticles can be found during avian development. These natural systems provide inspiration for designing more efficient microparticle facilitated drug-delivery systems. In this study, the formation and re-absorption of calcium carbonate crystals were tracked during Gallina N. meleagris embryogenesis and early postnatal development. The study demonstrated that the formation of calcium carbonate microparticles, as calcium is transferred from the eggshell into the egg sac, is a process of calcium preservation. X-ray diffraction showed that calcium carbonate crystal is mainly preserved in the vaterite isoform. Calcium incorporated into the yolk sac during this process can be easily assimilated as necessary during postnatal development. Eons of evolution have yielded a calcium preservation process that produces an iso-form of crystalline calcium most readily absorbed by the organism. Our previous results indicate that this biological system is likely a lyotropic process, the method that is currently being used for the production of microparticle drug delivery systems. In this work, our data suggests that calcium carbonate crystal can also initiate its crystallization from the center of liquid crystal, recognizable by a chimeric thermal phase transition. Our work provides valuable information for designing more efficient microparticle for drug-delivery.