Modulation Of Colloidal Selenium On The Growth Of Calcium Oxalate Crystal

In this paper, the interaction between elemental selenium nanoparticles （nanoSe⁰）and calcium oxalate （CaC₂O₄） crystals was investigated. We discussed the mechanismof CaC₂O₄crystals’ growth, which were modulated by free nanoSe⁰sol,nanoSe⁰-gallic acid （GA） sol and nanoSe⁰-bovine serum albumin （BSA） sol,respectively.The effects of nanoSe⁰sol on the nucleation, growth, aggregation and phasechange of CaC₂O₄crystals were investigated by scanning electron microscopy, X-raydiffraction, and Fourier transform infrared spectrometry. The results showed that themodulation effect related to the component of nanoSe⁰sol and its concentration.Free nanoSe⁰sol inhibited the nucleation of calcium oxalate monohydrate （COM）and promoted its growth in the range from0.01to0.02mmol/L, promoted theaggregation of COM crystals and induced the formation of COT crystals in the rangefrom0.04to0.06mmol/L, and inhibited the growth of （010） face on COM in therange from0.12to0.4mmol/L.GA could inhibit the nucleation and aggregation of COM and promoted itsgrowth. NanoSe⁰-GA sol could inhibit the growth of （010） face on COM. It alsopromoted quadrilateral COM with blunt edges in low concentration （0.005mmol/LnanoSe⁰-0.02mmol/L GA）, promoted the polymorphism in middle concentration（0.02mmol/L nanoSe⁰-0.08mmol/L GA and0.04mmol/L nanoSe⁰-0.16mmol/LGA） and induced the secondary nucleation of COM in high concentration （0.05mmol/L nanoSe⁰-0.2mmol/L GA,0.06mmol/L nanoSe⁰-0.24mmol/L GA and0.1mmol/L nanoSe⁰-0.4mmol/L GA）.BSA promoted the nucleation and growth of COM in low concentration(<1.0×10^-5mmol/L) and induced the formation of COD and COT crystals in highconcentration (>2.0×10^-5mmol/L). The nanoSe⁰could interact with BSA and made thestructure of BSA become more orderly, and promoted the nucleation of COM on thesurface of BSA. In high concentration (1.6×10^-3mmol/L nanoSe⁰-2.0×10^-5mmol/LBSA,3.2×10^-3mmol/L nanoSe⁰-4.0×10^-5mmol/L BSA and4×10^-3mmol/L nanoSe⁰-5.0×10^-5mmol/L BSA), nanoSe⁰-BSA promoted the round or heart-shapedaggregation of CaC₂O₄crystals which contained COM, COD and COT.