Design of smart temperature-sensitive terpolymeric hydrogel for multi-applications in liquid chromatography.

Hydrogels with a unique three-dimensional network structure have been widely used in a variety of fields. However, hydrogels are prone to swelling under water-rich conditions, which severely limits their application in liquid chromatography. Therefore, producing a hydrogel with reliable performance and good mechanical property is essential. Smart temperature-sensitive chromatographic packings have attracted extensive attentions in recent years. In this work, sodium 4-styrenesulfonate and 1-octadecene were introduced into the poly(N-isopropylacrylamide) hydrogel to improve mechanical property and separation performance. As a consequence, a smart temperature-sensitive terpolymeric hydrogel modified silica stationary phase (ION-hydrogel@SiO2) was synthesized for multimode liquid chromatographic separation. It was found that this new ION-hydrogel@SiO2 column exhibited excellent chromatographic separation ability for a wide range of analytes. To a certain extent, this new column has a higher chromatographic separation efficiency compared to the commercial C18 column and XAmide column. Moreover, the use of low proportion of organic phase in chromatographic separation is conducive to the realization of green chromatography. By investigating the chromatographic separation mechanism, it has been demonstrated that the hydrogen bonding interaction is primarily responsible for the temperature-sensitive behavior of the hydrogel. Finally, the ION-hydrogel@SiO2 column was used for the determination of pyridoxine in the commercially available tablet samples. In conclusion, this study presents a feasible idea for the development of novel copolymer hydrogels as liquid chromatographic stationary phases.

Incorporation of copper ion promoted adsorption of anionic dye (Acid Yellow 36) by acrolein-crosslinked polyethyleneimine/chitosan hydrogel: Adsorption, dynamics, and mechanisms.

In this study, a novel adsorbent, A-PEI/CS-Cu2+, was developed by crosslinking polyethyleneimine/chitosan hydrogel with acrolein and loading it with copper ions. The adsorption process of A-PEI/CS-Cu2+ on the anionic dye acid yellow 36 (AY36) was investigated by kinetic, isothermal and thermodynamic modeling. It was noteworthy that A-PEI/CS-Cu2+ exhibited rapid adsorption with a 90 % removal rate achieved within just 5 min, which was much faster than the adsorption rate of A-PEI/CS without load of copper ions and showed its potential for rapid adsorption applications. The maximum adsorption capacity for AY36 could reach up to 3114 mg g-1. In addition, the high concentration of saline wastewater was found to have almost no effect on the adsorption reaction in the salt effect test experiment. In five desorption-regeneration cycle experiments, the sample exhibited good recyclability and regeneration performance. The driving force of the adsorption process mainly originated from the electrostatic interaction, hydrogen bonding, and intermolecular interaction, in which the addition of copper ions led to the enhancement of the electrostatic interaction and chelation between A-PEI/CS-Cu2+ and AY36. Overall, the findings suggest the excellent potential of A-PEI/CS-Cu2+ for rapid and efficient adsorption, as well as its suitability for practical applications in wastewater treatment.

Efficiently ion-enhanced adsorption of anion dyes by acrolein crosslinked polyethylenimine/chitosan hydrogel with excellent recycling stability.

A novel adsorbent acrolein crosslinked polyethylenimine/chitosan hydrogel (A-PEI/CS) was developed with excellent recycling stability and ion-enhanced effect on removing anionic dye (acid blue 93, AB93) from aquatic environment. For AB93, A-PEI/CS was such an adsorbent with the characteristics of high adsorption capacity up to 1212.4 mg/g and continuous recyle ability of more than 15 times. After 15 desorption-regeneration cycles, the removal rate of A-PEI/CS for AB93 could still be as high as 96 % with imperceptibly downward trend. In addition, the addition of salts (KCl, NaCl and CaCl2) could promote the adsorption of A-PEI/CS, and the removal rate would be enhanced with increasing concentration of the salt. The effects of pH (2-7), contact time (30-600 min), temperature (30-50 °C) on the adsorption performance of A-PEI/CS were systematically examined. Furthermore, the physicochemical properties of the adsorbent were analyzed by FT-IR, XPS and zeta potential. The adsorption mechanism can be explained by electrostatic interaction, hydrogen bond interaction, chemical interaction. Intriguing to note that, the adsorption energy of adsorbents was investigated by molecular simulation, and the low pH and common salt environment can promote the adsorption effect, indicating that the prepared adsorbent has excellent application value in the treatment of practical high-salinity wastewater.

[Separation and purification of flavonoids from Smilax glabra by macroporous adsorption resin].

OBJECTIVE: To investigate the process of separating and purifying flavonoids from Smilax glabra. METHOD: With the yield of flavonoids as index, the optimum process of separating and purifying flavonoids from S. glabra Roxb was screened by static and dynamic adsorption tests. RESULT: The static saturated adsorption capacity of D101 macroporous resin to flavonoids of S. glabra was 45.6 mg x g(-1) (dry resin). The optimum conditions of dynamic adsorption and elution were as that the pH, the concentration, the adsorption velocity of the extracting solution, and the adsorption capacity were 6.00 +/- 0.20, 4.2 mg x mL(-1), 2 mL x min(-1) and 15 mL, respectively. The adsorbed resin column was washed by 100 mL 60% ethanol with pH value of 8.00 +/- 0.20 at the eluting velocity of 3 mL x min(-1) after washed by 100 mL distilled water. CONCLUSION: The flavonoids of S. glabra was able to be easily separated and purified by D101 macroporous resin under the optimum conditions above, and the recovery rate was higher than 90%. The content of obtained flavonoids reached 62.6%, which was 2 times of the content before purification.

Selective adsorption and recycle of Cu2+ from aqueous solution by modified sugarcane bagasse under dynamic condition.

Tetraethylenepentamine modified sugarcane bagasse was prepared and applied to test its feasibility in removing and recovering Cu2+ from wastewater under dynamic condition. Results showed that the Cu2+ could be selectively absorbed from wastewater by the modified SCB fixed bed column. To understand the adsorption mechanism, Cd2+ had been selected as the model interfering ion to investigate how co-ions influence the adsorption of Cu2+ on the sorbent. It was observed that the adsorption capacity of the sorbent for Cu2+ (0.26 mmol g-1) was significantly higher than that of Cd2+ (0.03 mmol g-1), even when the Cd2+ initial concentration was 100 times higher than that of Cu2+ in the binary system. This finding indicated that the presence of Cd2+ in the solution exerted negligible influence on the adsorption of Cu2+ on the modified SCB. The selectivity of the modified sorbent was further confirmed in the Cu/Cd/Mg/Pb/K quinary system. Further analysis to dynamic adsorption experiment illustrated that, due to the presence of amine groups, the modified SCB showed strong coordination ability to Cu2+, which allowed the other adsorbed ions (e.g., Cd2+) desorbed. This high adsorption selectivity toward Cu2+ suggested that this prepared sorbent would be a promising candidate for removing and recovering Cu2+ from wastewater.

[Apoptotic effect of bcl-XL antisense oligodeoxynucleotide mediated by lipofectin on cell strain CNE-2Z].

BACKGROUND & OBJECTIVE: Recent studies have shown that overexpression of bcl-XL was detected in human nasopharyngeal carcinoma (NPC) cell strain CNE-2Z, suggesting it may play a pivotal role in tumorigenesis of NPC. The current study was designed to explore the effect of bcl-XL antisense oligodeoxynucleotide (ASODN) on CNE-2Z. METHODS: A 20-mer gapmer ASODN with a full phosphorothioate backbone targeting a sequence unique of the bcl-XL coding region was artificially synthesized. Bcl-XL ASODN was transfected into CNE-2Z cells through lipofectin. The survival rate was assessed by MTT assay and internucleosomal fragmentation of genomic DNA was detected by agarose gel electrophoresis. Apoptotic changes after treatment with ASODN were observed by fluorescence microscopy and flow cytometry. RESULTS: MTT assay showed that the proliferation of CNE-2Z cells decreased significantly after treatment with ASODN/Lip as compared with control (P < 0.01). ASODN/Lip reduced the proliferation of CNE-2Z in a dose-dependent manner. After treatment with ASODN/Lip for 36 hours, most cells stained with Hoechst 33258/Pl exhibited apoptotic cell morphology such as cell shrinkage, nuclear condensation, and nuclear fragmentation under fluorescence microscope; a apoptotic peak appeared on flow cytometry; a ladder-like pattern of DNA fragmentation appeared on agarose gel electrophoresis. CONCLUSION: ASODN can inhibit proliferation of CNE-2Z cells and induce apoptosis of CNE-2Z cells. The results suggest that bcl-XL is a promising target for gene therapy of NPC.