Calcium Oxalate Crystal Growth And Inhibition

It's well-known that nucleation consisted of homogeneous nucleation and heterogeneous nucleation. The organic matrix used as the template to induce inorganic crystal growth and simulate the biomineralization is actually to promote heterogeneous nucleation and inhabit homogeneous nucleation. Urinary stone is a kind of product of unusual biomineralization. It is made up of inorganic crystal and organic matrix. The major composition of crystals is calcium oxalate, it crystallizes with very different crystallization kinetics, e.g. monodinic monolydrate (COM), tetragonal dihydtate (COD) and triclinic trihydrate (COT). COM is easy to form urinary stones because it has stronger affinity for renal tubule cell membranes than COD, COT. The main composition of the organic matrix of urinary stones is protein and polysaccharide etc., they play important roles in the formation of urinary stones. Biomineralization is a complicate process, which is difficult to study in the original situation inside the organism. To prophylaxis and cure of urinary stones, imitating the biomineralization out of the organism and studying the formation mechanism of urinary stone are very important to the health of human beings.In this paper, monolayer, microemulsion and biomolecule were selected as the template to induce crystal growth of calcium oxalate. The effect factors of them were discussed.Octadecanoic acid (OA) /octadecylamine (OAM) mixed monolayer were absorbed by HSA from the observation of surface pressure-molecule area (n-A) isotherms, differentiated curves of 0A/0AM monolayers and UV-vis, FT-IR spectra and fluorescence emission spectra of 0A/0AM LB film. The property change of 0A/0AM monolayer led to the change of crystal growth induced by the monolayer. When the concentration of HSA in subphases containing CaC2O4 supersaturated solution rises from 0.00% (wt%) to 0.10%, COT, COD and COM form beneath OA/OAM monoalyer, respectively. The size of COT crystal increases with the concentrations of HSA rising, it suggests that HSA can promote the growth of COT crystal. COM only forms under certain conditions. The formation process of COMcontains mainly three stages, i.e., COT, transitional crystals and COM. The transition from COT into COM takes about 480 h. 1,2-bis(O-aminophenoxy) ethane-N,N,N,N-tetracetic acid (2-BAPTA) is synthesized and used to prohibit the formation of COM, it suggest that 2-BAPTA may play an important role probably in prophylaxing and prohibiting urinary stone in the future.P-Octyl polyethylene glycol phenylether(OP)/ iso-octyl alcohol(IOA)/ cydohexane(CH)/ water reverse microemulsion was selected as simulation system and surfactants in microemulsion were used as template to induce CaC2O4 crystal growth. In OP/OIA/CH/water reverse microemulsion, CaC2O4 crystallized on the Ca2+-rich (101) axis of COM. Crystal growth of CaC2O4 was induced mainly by amino acids after the addition of certain concentration of amino acids (tryptophan, tyrosine, asparticacid) to OP/OIA/CH/water reverse microemulsions. The charges properties taken on the surfaces of amino acids had important effects on crystal growth. CaC2O4 crystallized on the (020) axis of COM when positive charges were taken on the surfaces of amino acids. Amnio acids could promote CaC2O4 to crystallize on the Ca2+-rich (101) axis of COM when negative charges were taken on their surfaces. Trp, Tyr and Asp could promote orientation growth of (101) face of COM more and more easily. The experiments suggested that Trp, Tyr, Asp or protein containing these amino acids in human body may promote the formation of urinary stone.Different from many kinds of crystal morphologies of CaC2O4 formed in bulk aqueous solution, uric acid template prohibited the formation of COT, but promoted the orientation growth of (020) face of COM and (100) face of COD. While the mixture of citrate and uric acid obviously inhabited crystal growth of COT, COD and orientation growth on (020) face of COM. CaC2O4 crystallized on the Ca2+-rich (101) axis of COM. It implies that the mixed t...