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Streptococcal protein G (SPG), which is an antigen of the Streptococcus sp. cell wall, is important due to its high specificity to immunoglobulin (Ig), as compared with staphylococcal protein A. However, the cost of commercial recombinant (r)SPG has so far hindered further research into the application of rSPG. Efficient high cell density fermentation of genetically modified Escherichia coli and purification technology have previously been studied as a means to obtain rSPG. In the present study, the immunological characterization of purified rSPG was compared with commercial SPG via western blot analysis. The results of the present study demonstrated that the IgG-binding capacity of purified rSPG was markedly higher, as compared with commercial SPG. Furthermore, purified rSPG cross-linked with Q Sepharose® Fast Flow exhibited excellent affinity with IgG in murine serum. In order to obtain relatively pure and accurate rSPG, the purified rSPG was identified by Nanoflow Liquid Chromatography-Mass Spectrometry (MS)/MS spectrum. The results indicated that the two peptide fragments of purified rSPG corresponded to the Streptococcus sp. GX7805 protein G as listed in the National Center for Biotechnology Information database. The method described in the present study offers a novel practical method for the verification of rSPG in relatively pure form, in order to purify IgG or carry out immunolabeling processes. [ABSTRACT FROM AUTHOR]

Thiol-functionalized dialkylimidazolium bromide was synthesized, and used as a stabilizer to prepare monodisperse silver nanocrystals through a facile one-pot aqueous approach. It is shown that the multipurpose ligands play a vital role in improving the performance of nanocrystals. The mechanisms of dialkylimidazolium-mediated promotion were analyzed on the basis of the physicochemical properties of the specifically designed ligand. [ABSTRACT FROM AUTHOR]

The design of green and ingenious strategies for the fabrication of anisotropic nanoparticles and their assembly is particularly important in the advancement of nanoscience and nanotechnology but still remains an enormous challenge. In this work, the Ag films, with variously shaped particles as building blocks, were successfully prepared at the interface of different ionic liquids and water (ILs-H2O) under ambient conditions only by using ILs with different cationic structures. The as-prepared Ag films with different morphologies were characterized and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction. The possible growth mechanisms were also suggested for the formation of differently morphological Ag films at the ILs-H2O interface. The as-obtained Ag films could be directly applied to perform surface-enhanced Raman scattering (SERS) studies. It was found that the nanobelt-contructed Ag films prepared at the interface of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N8881][Tf2N]) and water exhibited striking SERS sensitivities and good reproducibility. [ABSTRACT FROM AUTHOR]

Understanding of the specific salt effect on the aggregation behavior of ionic liquids (ILs) is relevant to multiple applications. In this work, the influence of a series of 15 salts on the aggregation behavior of [C10mim]Br in aqueous solutions has been investigated by conductivity, fluorescence, and dynamic light scattering. It was shown that NaCl, NaBr, NaI, CH3CO2Na, NaSCN, NaNO3, NaBrO3, NaClO3, C6H5COONa, Na2CO3, Na2SO4, Na2C4H4O6, and Na3CH5O7have salting-out effect, whereas FeBr3and AlBr3have salting-in effect on the aggregation of [C10mim]Br in aqueous solutions. The effect of anions of the added sodium salts on the critical aggregation concentration (CAC), degree of anionic binding (β), and aggregation number (Nagg) of the IL basically follows the Hofmeister series, and the CAC values decrease but the β and Naggvalues increase with increasing concentration of the salts. Hydrophobicity of the anions is suggested to play important roles in the salt effect on the aggregation of [C10mim]Br in aqueous solutions. Furthermore, the IL aggregates were found to grow slowly as the increase of the salt concentrations under studied static conditions, and resulting in the increased aggregation number of the IL. These results are expected to be useful in the applications of ionic liquids. [ABSTRACT FROM AUTHOR]

Densities, conductivities, and polarity indexes of pyrene for aqueous solutions of a series of ionic liquids CnmimBr (n4, 6, 8, 10, 12 ) and C4mimBF4have been determined at 298.15 K as a function of ionic liquid concentrations. It was shown that possible aggregation appeared for the ionic liquids in aqueous solutions except for C4mimBr. The critical aggregation concentration (CAC) of the ionic liquids, the ionization degree of aggregates (), the standard Gibbs energy of aggregation (%@mt;sys@%%@ital@%G%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%), the limiting molar conductivity (%@mt;sys@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%), and the standard partial molar volume (%@mt;sys@%%@ital@%V%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%) for the ionic liquids were derived from the experimental data. The dependence of the CAC, %@mt;sys@%%@ital@%G%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%, %@mt;sys@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%, and %@mt;sys@%%@ital@%V%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@%on the length of the alkyl chain of the cations was examined. It was further suggested from volumetric data that a micelle was formed for C8mimBr, C10mimBr, and C12mimBr in aqueous solutions. Their apparent molar volumes at the critical micelle concentration (V,CMC), apparent molar volumes in the micelle phase (%@mt;sys@%%@ital@%V%@rsf@%%@sx@%%@be@%mic%@sxx@%%@mx@%), and the change of their apparent molar volume upon micellization (V,m) were calculated by application of the pseudophase model of micellization. In addition, the average aggregation number of CnmimBr (n8, 10, 12 ) has been determined by the steady-state fluorescence quenching technique, and predicted from a simple geometrical mode. It is found that the experimental values are in good agreement with the predicted ones. [ABSTRACT FROM AUTHOR]