Facial on-line enrichment of glycoproteins by capillary electrophoresis with boronate-functionalized poly(glycidyl methacrylate) microparticles coated column.

A facial and rapid method for glycoproteins enrichment by capillary electrophoresis was developed. The 3-aminophenylboronic acid-functionalized poly(glycidyl methacrylate) microparticles (PGMA@APBA) were attached to the capillary inlet (length of ∼1.5 cm) by electrostatic self-assemble action to prepare a partially coated capillary column. The process is simple and reversible, allowing for easy renewal of the PGMA@APBA coating when its enrichment efficiency decreases. By utilizing the coated column, glycoproteins can be enriched within 2 min. The column exhibits a specific enrichment for glycoproteins and can be consecutively used for approximately 60 runs. The relative standard deviations (RSDs) of peak area of run-to-run (n = 5) and batch-to-batch (n = 3) were 1.5 % and 1.0%, respectively. The method was successfully applied to enrich glycoproteins from 1 × 1012-fold diluted real egg white sample, indicating its practical applicability.

Open-tubular capillary electrochromatography with hydroxypropyl-ß-cyclodextrin imprinted polymers: hybrid polyhedral oligomeric silsesquioxane as a coating for enantioseparation.

A hydroxypropyl-ß-cyclodextrin (HP-ß-CD) imprinted coating based on polyhedral oligomeric silsesquioxane (POSS) for open tubular electrochromatography was prepared. The mixture of methacryl-POSS (MA0735), HP-ß-CD (template), methacrylic acid (MAA, monomer), N,N'-methylenebisacrylamide (MBA, crosslinker) and toluene-dimethyl sulfoxide (porogen) was used to synthesize the chiral selective coating. The influence of synthesis parameters on the imprinting effect and separation performance, including the amount of HP-ß-CD, POSS, and MAA, was investigated systemically. The optimum polymerization was prepared by mixing HP-ß-CD, MA0735, MAA, and MBA with the molar ratio of 1 : 1.87 : 1.60 : 1.60. Five racemates were separated by the modified capillary columns using aqueous buffer. Column efficiency on the POSS-based MIPs coating column was greater than 22 000 plates/m. MIPs-POSS hybrid coating capillaries had improved resolution (3.36 times) and the greatest resolution was up to 6.15 within 10 min.

Colorimetric determination of cysteine by a paper-based assay system using aspartic acid modified gold nanoparticles.

A method is described for cysteine (Cys) determination on paper-based analytical devices using aspartic acid modified gold nanoparticles (Asp-AuNPs). The Asp-AuNPs were characterized by their size, zeta potential, and UV-visible absorption spectrum. After the addition of Cys, it will interact with Asp-AuNPs selectively and leads to the aggregation of Asp-AuNPs. A color change from red to blue can be observed on the paper-based analytical devices. The results were recorded using a cell phone and subsequently analyzed using the Photoshop software. The ratiometric color intensity at red channel and blue channel (Red/Blue) increased linearly in the range 99.9-998.7 µM for Cys (R = 0.9984), and the limit of detection was 1.0 µM. The effects of assay conditions have been investigated and are discussed. The Cys concentration was determined as (0.27 ± 0.02 mM) in human plasma, and the recovery was from 99.2 to 101.1%. Graphical abstract Schematic representation of the paper-based assay system using aspartic acid modified gold nanoparticles (Asp-AuNPs). The ratiometric color intensity method was used for the cysteine (Cys) determination.

A paper-based colorimetric assay system for sensitive cysteine detection using a fluorescent probe.

A fluorescent probe for the colorimetric detection of cysteine (Cys) was synthesized by combining resorufin with 7-nitrobenzofurazan. The resultant probe was characterized by FT-IR spectroscopy, fluorescence detection, mass spectrometry and NMR spectroscopy. After reacting with Cys, resorufin is released and the color changes from light yellow to red on paper-based analytical devices. The results were recorded using a common cell phone and subsequently analyzed using Photoshop software. The color intensity of the RGB channel increased linearly in the 0.04 to 70.04 µM Cys concentration range when the probe concentration was 2.6 mM (R = 0.9965), and the limit of detection was 16 nM. The effects of detection conditions have been investigated and are discussed. The interference deviations of 13 substances to Cys were in the range of -2% to +2%. The Cys concentration was determined as 270.8 ± 19.3 µM in human plasma, and the recovery was from 99.7% to 100.4%. The work demonstrates the potential of the method to detect Cys in real samples with low cost and high sensitivity.

A colorimetric assay system for dopamine using microfluidic paper-based analytical devices.

We report the colorimetric detection of dopamine (DA) on microfluidic paper-based analytical devices (µPADs) using an oxidation-reduction method. Here, dopamine reacts with ferric chloride forming reduced Fe2+ that subsequently reacts with phenanthroline to form the red tris(1,10-phenanthroline)iron(II) complex. The devices were fabricated by wax printing and changes in color intensity were recorded using a common cell phone. Subsequent analysis using Photoshop software, yielded a limit of detection (LOD) for DA of 0.37 µmol/L with a linear range of 0.527-4.75 µmol/L and relative standard deviation of 0.11% (inter-day) and 0.15% (intra-day) for n = 15 paper chips. The effects of detection conditions have been investigated and are discussed. Cow serum samples and human blood serum and plasma samples were detected. The work, herein, demonstrates the potential of this method as a low cost and rapid colorimetric technique to detect DA in real samples.

Using open-tubular capillary electrochromatography with part-coating column for binding constants determination of ß2 -adrenergic receptor with seven drugs.

An open-tubular capillary electrochromatography method has been developed for the determination of binding constants between ß2 -adrenergic receptor (ß2 -AR) and seven drugs. ß2 -AR was oriented immobilized onto one part of inner surface of capillary via microwave-assisted technical synthesis. According to the linear relationship between coating length and the apparent mobility of analyte, the binding constant (Kb ) can be obtained by related theories and equations. The order of Kb values between drugs such as adrenaline hydrochloride, norepinephrine bitartrate, and propranolol hydrochloride with ß2 -AR is well consistent with that reported in the literature. By the method, Kb values between four extracts of Radix Paeoniae Rubra and ß2 -AR were also successfully obtained. Subsequently, computer models were applied to interpret the CEC experiments. And the results proved to be in good agreement with the method. The work, herein, demonstrates the potential of the method in drug-receptor affinity interactions evaluation and screening of lead compounds from natural sources.

A Colorimetric Sensor for the Highly Selective Detection of Sulfide and 1,4-Dithiothreitol Based on the In Situ Formation of Silver Nanoparticles Using Dopamine.

Hydrogen sulfide (H2S) has attracted attention in biochemical research because it plays an important role in biosystems and has emerged as the third endogenous gaseous signaling compound along with nitric oxide (NO) and carbon monoxide (CO). Since H2S is a kind of gaseous molecule, conventional approaches for H2S detection are mostly based on the detection of sulfide (S2-) for indirectly reflecting H2S levels. Hence, there is a need for an accurate and reliable assay capable of determining sulfide in physiological systems. We report here a colorimetric, economic, and green method for sulfide anion detection using in situ formation of silver nanoparticles (AgNPs) using dopamine as a reducing and protecting agent. The changes in the AgNPs absorption response depend linearly on the concentration of Na2S in the range from 2 to 15 µM, with a detection limit of 0.03 µM. Meanwhile, the morphological changes in AgNPs in the presence of S2- and thiol compounds were characterized by transmission electron microscopy (TEM). The as-synthetized AgNPs demonstrate high selectivity, free from interference, especially by other thiol compounds such as cysteine and glutathione. Furthermore, the colorimetric sensor developed was applied to the analysis of sulfide in fetal bovine serum and spiked serum samples with good recovery.

Construction of a Turn Off-On-Off Fluorescent System Based on Competitive Coordination of Cu2+ between 6,7-Dihydroxycoumarin and Pyrophosphate Ion for Sensitive Assay of Pyrophosphatase Activity.

The detection of pyrophosphatase (PPase) activity is of great significance in diagnosing diseases and understanding the function of PPase-related biological events. This study constructed a turn off-on-off fluorescent system for PPase activity assay based on PPase-regulated competitive coordination of Cu2+ between a water-soluble fluorescent probe 6,7-dihydroxycoumarin (DHC) and pyrophosphate (PPi). The probe DHC can coordinate with Cu2+ and consequently display on-off type fluorescence response. Furthermore, the in situ formed nonfluorescent Cu2+-DHC complex can act as an effective off-on type fluorescent probe for sensing PPi due to the higher coordination reactivity between Cu2+ and PPi than that between Cu2+ and DHC. The subsequent addition of PPase to the mixture containing Cu2+, DHC, and PPi leads to the fluorescence requenching of the system again (an off state) because PPase catalyzes the hydrolysis of PPi into orthophosphate in the reaction system. Under the optimum conditions, the decrease of the fluorescence intensity of DHC-Cu2+-PPi system was linear with the increase of the PPase activity in the range from 0.1 to 0.3 U. The detection limit was down to 0.028 U PPase (S/N = 3). Moreover, the as-established system was also applied to evaluate PPase inhibitor. This study offers a simple yet effective method for the detection of PPase activity.

Research on drug-receptor interactions and prediction of drug activity via oriented immobilized receptor capillary electrophoresis.

Oriented covalent immobilized ß2 -adrenergic receptor (ß2 -AR) CE (OIRCE) was developed to determine the interactions between a set of natural extracts of Radix Paeoniae Rubra (NERPR) and ß2 -AR, and to predict the activity of NERPR. The inner capillary surface is chemically bonded with stable ß2 -AR coating via microwave-assisted technical synthesis. The modified capillaries were characterized via infrared spectroscopy and fluorescence microscopy. Furthermore, the bonding amounts of ß2 -AR were first obtained via fluorescence spectroscopy method. In determining the amount of bonded ß2 -AR, the regression equation A  =  576 707C + 35.449 and the correlation coefficient 0.9995 were obtained. This result revealed an excellent linear relationship in the range of 2 × 10(-4)  mg/mL to 1 × 10(-3)  mg/mL. The normalized capacity factor (KRCE ) was obtained using OIRCE in evaluating drug-receptor interactions. Related theories and equations were used to calculate KRCE values from apparent migration times of a solute and EOF. The order of KRCE and the binding constant (Kb ) values between drugs and ß2 -AR was well consistent. The results confirmed that the OIRCE and KRCE values can be effectually used to investigate drug-receptor interactions, and OIRCE has the potential to predict drug activity and to select leading compounds from natural chemicals.

China's three-year health reform program and equity in sanitation improvement: a panel analysis.

BACKGROUND: Accessible improved sanitation is critical to child health, and inequities in improved sanitation can be interpreted as health inequities across socio-economic groups. From 2009 to 2011, the Chinese government invested 4.448 billion yuan for rural sanitation improvement through a 3-year health reform program. This study assesses the inequity of sanitation improvement in rural China from 2003 to 2011 and examines whether the 3-year health reform program promoted equity in sanitation improvement. METHODS: Data from the China Health Statistics Yearbooks of 2004 to 2012 and the National Bureau of Statistics of China were used to create the concentration curve (CC), concentration index (CI), and absolute concentration index (ACI) of improved sanitation. Data of central investment for sanitation improvement in each province of China for 2009, 2010, and 2011 was gained through correspondence and used to create the CC and CI for investment. RESULTS: Although the CIs of improved sanitation are lower than the CIs of the net income of rural residents, the latter have an obvious downtrend. The CIs of improved sanitation increased from 2003 until 2008 and started to drop in 2009. As a result, by 2011, the CIs of improved sanitation had reached their 2003 levels. The ACI of improved sanitation decreased slightly from 2003 to 2008, but declined sharply from 2009 to 2011. The CIs of central investment for 2009, 2010, and 2011 are negative and the CCs of central investment are above the line of absolute equality, indicating that investments had been concentrated more on poorer provinces and regions. CONCLUSIONS: The equality of rural residents' net income has been improving each year, whereas equity in sanitation improvement deteriorated from 2003 to 2008. However, equity in sanitation improvement has increased since 2009 due to central investment in sanitation improvement during the 3-year health reform program that benefits low-income areas more. It is clear that the 3-year health reform program played an important role in promoting the level and equity of sanitation improvement.

Interactions between isoprenaline hydrochloride and bovine serum albumin (BSA) in capillary zone electrophoresis and affinity capillary electrophoresis.

Capillary zone electrophoresis (CZE) and affinity capillary electrophoresis (ACE) were developed to investigate the interactions between isoprenaline hydrochloride (IH) and bovine serum albumin (BSA). In CZE, the binding constant (Kb) was 4.07 x 10(4) M(-1) (298 K) and 4.76 x 10(4) M(-1) (310K) using the Scatchard analysis. The number of binding sites (n) in this interaction was approximately one (n approximately equal 1). Furthermore, thermodynamic parameters, such as changes in Gibbs free energy (deltaG), enthalpy (deltaH), and entropy (deltaS) of the binding procedure were also obtained. At 298 K, deltaG, deltaH, and deltaS were -26.30 kJ x mol(-1), 10.02 kJ x mol(-1), and 0.12 kJ x mol(-) x K(-1), respectively. The deltaG at 310K was -27.76 kJ x mol(-1), whereas the deltaH and deltaS at 310 K were identical with that at 298 K. In ACE, a more reliable parameter, mobility ratio (M), was applied in the calculation of Kb. Kb (310K) obtained through this method was 9.80 x 10(4) and 9.24 x 10(4) M(-1) when IH and BSA were added to the buffer in varying concentrations, respectively. The obtained Kb may help in gaining some insights on the possible drug/protein interactions and in the early evaluation of the pharmacokinetic profile of the drug during cardiovascular drug screening.

Diaqua-bis-(2,2'-bi-1H-imidazole)-man-ganese(II) benzene-1,4-di-carboxyl-ate.

The asymmetric unit of the title compound, [Mn(C(6)H(6)N(4))(2)(H(2)O)(2)](C(8)H(4)O(4)), contains one-half each of the centrosymmetric cation and anion. The Mn(II) atom is coordinated by four N atoms [Mn-N = 2.2168 (14) and 2.2407 (14) Å] from two 2,2'-biimidazole ligands and two water mol-ecules [Mn-O = 2.2521 (14) Å] in a distorted octa-hedral geometry. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds consol-idate the crystal packing, which also exhibits π-π inter-actions between five-membered rings, with a centroid-centroid distance of 3.409 (2) Å.

Poly[(µ-3,5-dinitro-benzoato)(µ-3,5-dinitro-benzoic acid)rubidium].

The asymmetric unit of the title compound, [Rb(C(7)H(3)N(2)O(6))(C(7)H(4)N(2)O(6))](n), comprises an Rb(+) cation, a 3,5-dinitro-benzoate anion and a 3,5-dinitro-benzoic acid ligand. The Rb(+) cation is nine-coordinated by O atoms from four 3,5-dinitro-benzoate anions and three neutral 3,5-dinitro-benzoic acid ligands. The metal atom is firstly linked by four bridging carboxyl groups, forming a binuclear motif, which is further linked by the nitro groups into a two-dimensional framework along the [110] direction. A short O-H⋯O hydrogen bond between two adjacent carboxy/carboxylate groups occurs.

Poly[(µ(5)-3,5-dinitro-benzoato)rubidium].

The asymmetric unit of the title compound, [Rb(C(7)H(3)N(2)O(6))](n), comprises an Rb cation and a 3,5-dinitro-benzoate anion. The Rb cation is eight-coordinated by O atoms from five 3,5-dinitro-benzoate anions. On the other hand, each 3,5-dinitro-benzoate anion links five Rb cations with the carboxyl-ate groups as µ(3)-bridging. The metal atom is firstly linked by the carboxyl-ate groups into a chain along the c-axis direction, which is further linked by bonds between the Rb and nitro O atoms, giving a three-dimensional framework.

Tris(3-hy-droxy-imino-1-methyl-indolin-2-one) monohydrate.

There are three independent 3-hy-droxy-imino-1-methyl-indolin-2-one mol-ecules and a water mol-ecule in the asymmetric unit of the title compound, 3C(9)H(8)N(2)O(2)·H(2)O. The crystal packing is stablized by O-H⋯O and O-H⋯Nhydrogen bonds between 3-hy-droxy-imino-1-methyl-indolin-2-one mol-ecules and the water mol-ecule and weak π-π stacking inter-actions [centroid-centroid distances in the range 3.446 (2)-3.983 (2) Å], forming a two-dimensional network.

Spiro-[1,3-dioxolane-2,3'-indolin]-2'-one.

The title compound, C(10)H(9)NO(3), was synthesized by the condensation reaction of isatin (systematic name 1H-indole-2,3-dione) with glycol in presence of p-toluene-sulfonic acid. The indol-2-one ring system is essentially planar [N-C-C-C torsion angle = 3.1 (2)°], and the 1,3-dioxolane ring is slightly distorted. The crystal structure exhibits inter-molecular N-H⋯O hydrogen bonds.

1-(Morpholino-meth-yl)indoline-2,3-dione.

In the title compound, C(13)H(14)N(2)O(3), the morpholine ring displays a chair conformation, with the (2,3-dioxoindolin-1-yl)methyl group in an equatorial position. The crystal structure is stabilized by inter-molecular C-H⋯O hydrogen bonds.