Papers by Keyword: Dialysis

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Authors: Jian Guo Liu, Chang Zhen Chen, Jing Liu
Abstract: The objective of this work is to develop a novel dialysis process for the isolation of phosvitin from hen egg yolk avoiding the use of organic solvents and polyvalent metals. This bioseparation process consists of NaCl precipitation, heat treatment and dialysis, which was proposed on the basis of the property difference (especially solubility and thermostability) among yolk proteins. The native molecular mass of the purified phosvitin estimated by fast protein liquid chromatography on a Superdex 75 column was about 165 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed two bands around 35 kDa. The nitrogen to phosphorus atomic ratio of the purified phosvitin was 2.8 ± 0.2, with a yield of 87.1%. The phosvitin product had α-helix of 36%, β-sheet of 28% and random coil of 36% at pH 7.0, consistent with the literature values. This shows that the purified phosvitin folded with a reasonable secondary structure.
Authors: Sheng Min Zhang, W. Zhou, Jian Liu, L. Cheng, P.P. Chen
Abstract: A novel synthesis of nano-fluoride-substituted hydroxyapatite (nano-F-HAP) was successfully realized through dialysis process within 4 h, which required much shorter time than the methods reported so far. In new preparation, a dialysis was employed to purify unwanted ions. The removal efficiency of impurity ions in dialysis was evaluated by calculating the concentration of the representative irons NH4 + between the inner slurry and outer distilled water. Results showed that total dialysis efficiency came to 94.5%. The final products were characterized by XRD, HR-TEM, and FT-IR. The XRD and FT-IR results strongly supported substitution of F- for OH-, and the TEM pictures further indicated that the final crystals are about 100nm in length and about 20 nm in diameter without obvious aggregation. Therefore, comparing with traditional purifying processing, such a new synthesis provides a promising application for scale preparation of fine nano-F-HAP crystals.
Authors: Naoko Tomita, Isamu Rokugawa, Hiromi Toyama, Takao Yamamoto, Toshiaki Dobashi
Abstract: Anisotropic gelation has been studied by immersing chitosan in aqueous acetic acid sandwiched by a pair of square cover glasses into aqueous sodium hydroxide. The shape of the gel front line initially remained a square, whereas it approached a circle with immersion time. The time course of the distance between the side of the cover glasses and the gel front line xs was expressed initially as scaled proportional relationship (xs/L)2 =2K(t/L2), where t is the immersion time, L; the length of the side of the cover glasses and K; a constant. The characteristic behavior was independent of chitosan concentration.
Authors: Sheng Min Zhang, W. Hu, W. Zhou, J. Li, Y.H. Liu, Z.Y. Qiu
Abstract: Nano-sized zinc-substituted hydroxyapatite (nano-ZnHA) has stimulatory effect on bone formation and inhibitory effect on osteoclastic bone resorption in vivo. Nano-ZnHA with serial zinc fractions (0, 2, 5, 10 mol%) were synthesized by an improved precipitation method based on dialysis process. Transmission electron microscopy observation indicated that the increase of Zn fraction led to smaller crystallite. X-ray diffraction of the products revealed that some typical characteristic peaks of HA displayed when the Zn fraction was below 10%. Fourier transform infrared spectroscopy showed that the bending peaks of the group-OH in HA became wider with the increase of Zn fraction and it disappeared at 10 mol%. The current work demonstrated that zinc could substitute for calcium into hydroxyapatite in the limited range of composition by using dialysis process.
Authors: Shu Chen, Quan He, Jian Tang, Shan Bai, Yun Fei Long
Abstract: Fine CdS nanodots (~5 nm) have been prepared in aqueous solution under the control of ds-DNA via a novel alternating dialysis procedure, which have been characterized by TEM, UV-vis, fluorescence (FL) and resonance light scattering (RLS) spectra. The resultant well-dispersed CdS nanodots present a strong FL peak at 339 nm and RLS bands around 394 nm. Interestingly, it was found that the quenching of FL and the enhancing of RLS intensity are dependent on the concentration of Hg2+, both of which showed good linear relationship over the range of 0.01-100 mmol/L, with a detection limit (3s) as low as 0.91 nmol/L. Good selectivity of this method for Hg2+ analysis has also been checked over other metal ions.
Authors: Jian Guo Liu, Xue Fang Zhang, Jing Liu
Abstract: In the present work, a new dialysis process was proposed to isolate phosvitin from chicken egg yolk, which consists of NaCl precipitation, heat treatment and dialysis. The effects of several key operating parameters on the purity of phosvitin were examined. Under optimized conditions, the phosvitin purity obtained was about 86.3%, with a yield of 87.2%. The resulting phosvitin product had β-sheet of 78.5% at pH 2.0, consistent with the literature value. This shows that the purified phosvitin folded with a reasonable secondary structure.
Authors: Ying Ying Pei, Yang Xu, Yi Ze Sun, Da Yong Gao, Wei Ping Ding
Abstract: Bound solute dialysis in artificial liver support systems is one of approaches to remove protein-bound toxins from patients with liver disease. In this study, a theoretical mass transfer model for bound solute dialysis considering detailed local ultrafiltration was presented. Then, the numerical simulation was performed and the theoretical results were compared with the experimental data in two dialysis modes under various operating conditions, open-loop dialysis mode (OLM) and closed-loop dialysis mode (CLM).Our results show that the theoretical results agree well with the experimental data. The theoretical model presented here can be used to accurately predict the clearance of albumin-bound toxins and optimize the treatment strategy for clinical application.
Authors: Zhen Qing Hou, Shui Fan Zhou, Fei Cui, Yi Xiao Hang, Yun Feng Yi
Abstract: Hydroxycamptothecin (HCPT) loaded PLA nanoparticles were prepared by a facile dialysis method. Three main influential factors, PLA concentration, ratio of HCPT to PLA (wt/wt), dialysis bags with different molecule weight cutoff, were evaluated using an orthogonal design, gave the nanoparticles with an average diameter of approximately 226.8 nm and fine drug loading content (5.16%, w/w). The in vitro drug release studies exhibited a slow and prolonged release profile over 30 days. It is concluded that the new method to prepare HCPT-PLA nanoparticles resulted in improved formulation characteristics including small size, high drug loading capacity, and long sustained drug release.
Authors: Y.H. Liu, Sheng Min Zhang, L. Liu, W. Zhou, W. Hu, J. Li, Z.Y. Qiu
Abstract: Nano-sized β-tricalcium phosphate (nano-sized β-TCP) was synthesized by dialysis process using Ca(NO3)2·4H2O and (NH4)2HPO4 as starting materials. The time needed for the whole process is much shorter than other reported methods. In this new synthesis, dialysis was used to remove the unwanted ions, and the removal efficiency of impurity ion was evaluated by comparing the representative ion NH4 + between the original slurries and deionized water outside of the dialysis tube. The resulting powders were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), and chemical analysis. Results showed the final products are pure β-TCP. The pictures of high resolution-transmission electron microscope (HR-TEM) further indicated that β-TCP crystals are around 100nm in diameter.
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