Plasmon-Enhanced Ultrasensitive Surface Analysis Using Ag Nanoantenna.

Raman scattering and fluorescence spectroscopy permeate analytic science and are featured in the plasmon-enhanced spectroscopy (PES) family. However, the modest enhancement of plasmon-enhanced fluorescence (PEF) significantly limits the sensitivity in surface analysis and material characterization. Herein, we report a Ag nanoantenna platform, which simultaneously fulfills very strong emission (an optimum average enhancement of 105-fold) and an ultrafast emission rate (∼280-fold) in PES. For applications in surface science, this platform has been examined with a diverse array of fluorophores. Meanwhile, we utilized a finite-element method (FEM) and time-dependent density functional theory (TD-DFT) to comprehensively investigate the mechanism of largely enhanced radiative decay. PES with a shell-isolated Ag nanoantenna will open a wealth of advanced scenarios for ultrasensitive surface analysis.

[Fluorescence Properties of Single-Trp Peptide: Response to pH and Metal Ions].

Considering the important role of metal ions including copper ions are playing in human body, a novel single-Trp peptide WDAHSS was designed and synthesized in this study to achieve sensitive detection of copper ions via fluorescence spectroscopy. The intrinsic fluorescence of a tryptophan residue in WDAHSS, which was the only source of the molecular fluorescence, could be easily quenched with copper ions. By comparing fluorescence spectra of WDAHSS with those of tryptophan molecules at different pH values, the quenching mechanism of WDAHSS was explored in detail. Research showed that the histidine in WDAHSS bound copper ions with metal coordination. With participation of peptide bond, a square planar structure was formed. It was a consequent chelation of copper ions that caused the quenching of tryptophan residue. At the same time, this study discussed how pH conditions affected the fluorescence spectra of WDAHSS. Furthermore, association constants of copper ions towards WDAHSS were calculated through fluorescence measurements and fitting analyses. To enhance the anti-jamming ability to pH variation, the amino terminal of WDAHSS was intentionally acetylized, leading to a stable fluorescence emission under physiological pH conditions. Besides, WDAHSS was designed as a special structure to enhance the selectivity and biocompatibility of its sensitive detection of copper ions. Further studies on WDAHSS may help to improve the fluorescence imaging detection in vivo.

[Hepatitis B virus infection increases the incidence of immune infertility in males].

OBJECTIVE: To investigate the relationship between hepatitis B virus (HBV) infection and the incidence of male immune infertility. METHODS: Based on the levels of serum HBsAg, 3 124 infertile men were classified into an HBV-positive and an HBV-negative group and, according to the results of IBT tests, those with immune infertility were further divided into an HBV-positive and an HBV-negative group. Statistical analyses were made on the incidence rate of immune infertility and seminal parameters in the immune infertility patients of the HBV-positive and HBV-negative groups, the correlation of the number of HBV DNA copies in the serum with that in the seminal plasma of the HBV-positive patients, the association of the numbers of HBV DNA copies in the serum and seminal plasma with semen parameters, and the relationship of the number of HBV DNA copies in the seminal plasma with the incidence of immune infertility. Sperm concentration and the percentage of progressively motile sperm (PMS) were measured by computer-aided sperm analysis, sperm morphology determined by Diff-Quik staining, the level of HBsAg detected by ELISA, and the numbers of HBV DNA copies in the serum and seminal plasma calculated by RT-PCR. RESULTS: The incidence rate of immune infertility was significantly higher in the HBV-positive than in the HBV-negative group (20.3 vs 3.3%, χ2 = 187.5, P <0.01), and the percentage of morphologically normal sperm (MNS) was markedly lower in the HBV-positive than in the HBV-negative infertility patients (ï¼»3.9 ± 1.7ï¼½ vs ï¼»6.3 ± 2.2ï¼½%, P <0.05), but no statistically significant differences were observed between the two groups of infertile males in the semen volume, sperm concentration, or PMS (P >0.05). The number of HBV DNA copies in the serum was positively correlated with that in the seminal plasma (rs = 0.86, P <0.01) while both the number of HBV DNA copies in the serum and that in the seminal plasma were negatively correlated with PMS (r = －0.233 and －0.465, P <0.01) and MNS (r = －0.250 and －0.508, P <0.01). The incidence rate of immune infertility showed no statistically significant differences among the groups with different numbers of HBV DNA copies in the seminal plasma (P >0.05). CONCLUSIONS: HBV infection can increase the incidence rate of immune infertility in men and is correlated with the low quality of sperm.

[Precise and Rapid Detection of Glutathione by Using Novel Fluorescent Ag Nanoclusters].

Glutathione (GSH) is an important three-peptide molecule, which has the functions of antioxidation and detoxification, and plays a crucial role in the fields of biology, medicine and food science. It is involved in many important biochemical reactions in cells and body fluid, and the changes of GSH content reflect the specific health problems of human body. Current methods of GSH detection are always complicated, time-consuming and expensive instrument depended, such as surface enhanced Raman spectroscopy (SERS), electrochemical analysis, high performance liquid chromatography (HPLC) and so on. The probe's photochemical properties can be modified by the reaction between GSH and nanoclusters, which will result in the changes of fluorescence intensity and wavelength. In this paper, a new method to realize precise and rapid GSH detection is developed by using silver na-noclusters as a fluorescent probe, and simultaneously measures the probe's fluorescence intensity and wavelength. The synthesis of the fluorescence probe reported in this paper possesses the advantages of steps-simple and pollution free, and the GSH detection method has faster response, more accurate measurement and smaller relative error over the traditional methods. The good specificity of GSH detection among other molecules with the similar structure is further proved in control group experiments by comparing the differences of their fluorescence intensities and wavelength. The measurement accuracy is fully assured due to the insensitivity of the probe to a variety of salt ions and amino acids. This technique can be further employed in the intracellular detection and imaging of GSH.

[Cloning, expression and immuno-protection analysis of a gene encoding troponin T of Schistosoma japonicum (SjTnT)].

OBJECTIVE: To clone cDNA encoding troponin T of Schistosoma japonicum (SjTnT), and evaluate the protective efficacy induced by recombinant SjTnT in BALB/c mice against S. japonicum challenge infection. METHODS: The SjTnT gene was amplified from 28-day-schistosome cDNAs by PCR and then subcloned into pET28a(+). The recombinant SjTnT protein (rSjTnT) was expressed in Escherichia coli BL21 (DE3) cells. The serum specific to rSjTnT was prepared by immunized BALB/c mice with the recombinant antigen, and the immunogenicity of rSjTnT was detected by Western blotting and ELISA. The immuno-protective efficacy induced by rSjTnT in BALB/c mice was evaluated according to the reduction in worm and egg counts. RESULTS: The cDNA encoding SjTnT was successfully cloned and expressed in E. coli. Western blotting showed that rSjTnT had a good immunogenicity. The high level of specific IgG antibodies was detected, and 33.89% worm reduction and 43.94% liver egg reduction were obtained in mice vaccinated with rSjTnT combined with Seppic 206 adjuvant compared with those in the adjuvant control group. CONCLUSIONS: rSjTnT could induce partial immuno-protection against S. japonicum infection in BALB/c mice. This study provided a basic for understanding the biological function of SjTnT.

Study on the influence of cross-sectional area and zeta potential on separation for hybrid-chip-based capillary electrophoresis using 3-D simulations.

Hybrid chips combing microchips with capillaries have displayed particular advantages in achieving UV-vis and mass spectroscopic detection. In this work, systematic 3-D numerical simulations have been carried out to explore the influence of junction interface cross-sectional area and ζ-potential distribution on sample band broadening in hybrid-chip electrophoresis separation. In this case, the ratio of cross-sectional area of chip to capillary channel (S(ratio) ) is used as the parameter of the variation in junction interface cross-sectional area. Theoretical simulations demonstrated that the decrease of the S(ratio) would increase the separation efficiency in the hybrid-chip-based CE with uniform ζ-potential distribution. ζ-potential distribution along the axial direction of the channel also affects mass transport in hybrid-chip-based CE. Therefore, the effect of ζ-potential distribution has been considered in the 3-D simulation. Theoretical simulation results reveal that ζ-potential distribution rather than the interface cross-sectional area variation (S(ratio) ) controls the sample band broadening and manipulates sample separation efficiency in the hybrid-chip-based CE with non-uniform ζ-potential distribution. Both the theoretical simulations and experimental results show that optimal hybrid-chip CE separation efficiency can be achieved at S(ratio) =1.