A new fluorescent detection route for chloride ion was designed with Nitrogen-doped graphene quantum dots (N-GQDs), which were prepared by a traditional hydrothermal method with citric acid as carbon source and urea as nitrogen source. The prepared N-GQDs solution was light yellow, and the freeze-dried solid was black. It emitted blue light under ultraviolet light. Meanwhile, The N-GQDs were characterized by TEM, XRD, UV-Vis and fluorescence, the results indicated that the N-GQDs had good dispersibility, photostability and excitation independent emission fluorescence. After addition of Ag+ solution, Ag+ combined to the surface functional groups of N-GQDs, resulting in an obvious quenching of the fluorescence intensity of N-GQDs. Nevertheless, the fluorescence intensity recovered significantly with the addition of Cl- to the N-GQDs/Ag+ system, this was because of AgCl was formed due to the “soft hard acid base principle”. The change of fluorescence intensity had a linear response to the chloride ion concentration in the range of 8.5-300 μmol L-1, with a detection limit (LOD) of 0.1 μmol L-1. To authenticate the application, the proposed method has been successfully used for quantitative analysis of chloride ion in real samples, including artificial sweat and environmental water.

A novel dual-signal amplificatory electrochemiluminescence (ECL) deoxyribonucleic acid (DNA) biosensor was designed for the determination of Hg2+. One amplification unit was gold nanoparticles (AuNPs) modified on a glassy carbon electrode, and the other was single-stranded DNA (ssDNA) (with amino at the 3’ terminal and thiol at the 5’ terminal) labeled with a carboxyl-functionalized Ru@SiO2 nanoparticles (Ru1@SiO2) as a nanoprobe. The ECL biosensor was obtained through a strong gold-sulfur bond between Au on AuNPs modified electrode and thiol in the nanoprobe. In the presence of Hg2+, the ECL signal reduced because the T-Hg2+-T existed between the ECL nanoprobe and the complementary DNA (c-DNA), which exhibited a sensing platform for the detection of Hg2+. The results revealed that the reduced ECL intensity was linearly proportional to the logarithm of the Hg2+ concentration in the range of 1.0 pmol L-1-100 nmol L-1 with limit of detection 0.02 pmol L-1. The proposed method was applied for the analysis of Hg2+ in the river water and the results were in good agreement with that obtained by atomic fluorescence spectroscopy.

A novel electrochemiluminescence (ECL) biosensor for the determination of lipopolysaccharide (LPS), a biomarker of endotoxemia, was designed. The nanoprobe (Ru1@SiO2-peptide) with a specific peptide (CIGKLHSAGK) labeled with a carboxyl functionalized Ru@SiO2 (Ru1@SiO2) was prepared by the acylation reaction. The ECL peptide biosensor was obtained by the strong gold-sulfur bond between Au on the gold electrode (AuE) surface and thiol group in the peptide. In the present of LPS, the peptide on the ECL biosensor can capture effectively LPS and the LPS/peptide/AuE was fabricated. When the Ru1@SiO2-peptide nanoprobe was bound, a sandwich compound of Ru1@SiO2-peptide/LPS/peptide was formed, and Ru(bpy)32+, in the sandwich compound, will do the ECL performance. The effective ECL amplification of Ru1@SiO2 exhibited excellent analytical performance to LPS with a wide detection linear range of 1.0~500 ng mL-1 and the detection limit was 0.3 ng mL-1. The biosensor could provide an evaluate of LPS expression on the bacteria surface and guide a new path to the clinical analysis of LPS related diseases.

A simple and sensitive electrochemical impedance spectroscopy (EIS) biosensor was designed for the determination of lipopolysaccharide (LPS). The gold nanoparticles (GNPs) were electrochemically deposited on the glassy carbon electrode as a base electrode and the biosensor was fabricated by self-assembling a special peptide (GIGKLHSAGKF) used as molecular recognition onto the GNPs surface according to the Au–S bond. Polyethylene glycol and 6-mercapto-1-hexanol were used to block the remaining sites of the modified electrode surface. When binding of LPS, the biosensor had a good response to different concentrations of LPS and the charge transfer resistance of the biosensor was directly related to the logarithm of LPS concentrations in the range of 0.01 pg mL-1-1.0 ng mL-1 with a limit of detection of 2.0 fg mL-1. The characteristics of the electrochemically deposited GNPs and the optimization concentration and the self-assembly time of peptide, as well as the performance of the EIS biosensors for LPS were investigated. The biosensor was used for real serum sample determination with satisfactory results.

A novel electrochemiluminescence (ECL) biosensor for highly sensitive and selective detection of Ag+ is developed based on the sensitive “turn-on” structure-switching trigeminal structure of deoxyribonucleic acid (DNA-TS). DNA-TS consists of three oligonucleotides hybridized to form three double-stranded DNA like Y-shaped DNA structure. The formation of DNA-TS makes the ECL sign Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2 of reporter probe approach to the electrode surface and thus increase the ECL signal intensity. The “signal-on” ECL biosensor could detect Ag+ concentration in the range from 1.0 × 10-11 to 3.2 × 10-9 mol L-1, and the limit of detection is 3.0 × 10-12 mol L-1. The strategy is sensitive and rapid. This approach could be extended to the design of sensors for other desired heavy metal ions as well. Such ECL sensors are promising for sensitive detection of other heavy metal ions.

Chitosan-Ru2(bpy)32+-SiO2 composite nanoparticles (CRuS NPs) were prepared by reverse microemulsion method for the electronic attraction between negative charge of hydroxyl groups in chitosan and positive charge in Ru2(bpy)3 2+. Based on the multi-walled carbon nanotubes (MCNT)/Nafion composite membrane technology, CRuS NPs was effectively and steadily immobilized on the surface of a glassy carbon electrode. The CRuS NPs synthesized were characterized by transmission electron microscope (TEM), UV-Vis spectroscopy and fluorescence spectroscopy, while the modification was confirmed by cyclic voltammetry and electrogenerated chemiluminescence (ECL). The ECL studies revealed that the sensor had a good response to different concentrations of tiapride hydrochloride and the increased ECL intensity was directly related to the logarithm of tiapride hydrochloride concentrations in the range from 0.01 to 3.0 µmol L-1 with a detection limit of 6.0 nmol L-1. The sensor was successfully applied to the determination of tiapride hydrochloride in pharmaceutical.

Abstract Purpose: To investigate the impacts of albumin synergized with hydroxyethyl starch (HES) on early microvascular albumin leakage after major abdominal surgery in rabbits. Methods: Forty male Japanese rabbits were randomly divided into four groups: the control group, the saline group, the albumin group, and the Syn group (hydroxyethyl starch+albumin). The latter three groups were performed gastrectomy plus resection of pancreatic body and tail and splenectomy. The serum albumin concentration was detected before and 48h after surgery, and the conditions of mesenteric microvascular leakage in these 4 groups were observed under microscope 48 h after surgery to calculate the leakage rate. Results: Compared with the saline group, the albumin group and the Syn group exhibited significantly increased serum albumin concentrations 48h after surgery (P<0.05). The albumin leakage rate was the most obvious in the albumin group, followed by the saline group, while that in the Syn group was the minimal, and there existed significant differences among these groups (P<0.05) . Conclusion: Simple administration of albumin in the early stage after major abdominal surgery could increase the albumin leakage, while the synergization of albumin and hydroxyethyl starch could reduce the albumin leakage.

Water storage change has implications not only for the hydrological cycle, but also for sustainable water resource management in especially semi-arid river basins. Satellite/remote sensing techniques have gained increasing application in monitoring basin and regional hydrological processes in recent decades. In this study, the latest version of GRACE (Gravity Recovery and Climate Experiment) is used to estimate total water storage change in the Hai River basin (HRB) of Northern China for the period January 2003 to December 2006. Time-series comparisons show a good agreement between the estimated storage change from the GRACE satellite data and in situ hydrological measurement data at especially the seasonal cycle with R = 0.82 and RMSE = 17.25 mm. The good agreement suggests that GRACE detects storage change in the 318 866 km² HRB study area. It also implies that the in situ hydrological measurements of soil moisture and groundwater sufficiently characterise storage change in the semi-arid river basin. Change in soil moisture storage is less than that in saturated storage, suggesting that storage depletion in the basin is mainly in the saturated zone. Both the GRACE and hydrological measurement data indicate storage loss in the range of 12.72 to 23.76 mm/yr - a phenomenon that has been detected in previous studies in the basin. GRACE hydrology data could therefore be handy in monitoring storage dynamics and water availability in the study area. As GRACE data are available for virtually every region of the world, their application in conjunction with hydrological models could improve hydrological studies. This may lead not only to water balance closures, but also to sustainable water resource management at basin to regional scale.