JOURNAL OF BIOMEDICAL OPTICS
·
2007
·
IF 2.87
Doriel Verdes,Thomas Ruckstuhl,Stefan Seeger
We report a new two-channel fluorescence microscopy technique for surface-generated fluorescence. The realized fluorescence microscope allows high resolution imaging of aqueous samples. The core element of the instrument is a parabolic mirror objective that is used to collect the fluorescence at large surface angles above the critical angle of the water/glass interface. An aspheric lens, incorporated into the solid parabolic element, is used for diffraction-limited laser focusing and for collecting fluorescence at low angles with respect to the optical axis. By separated collection of the fluorescence emitted into supercritical and subcritical angles, two detection volumes strongly differing in their axial resolution are generated at the surface of a glass cover slip. The collection of supercritical angle fluorescence (SAF) results in a strict surface confinement of the detection volume, whereas collecting below the critical angle allows gathering the fluorescence emitted several microns deep inside the sample. Consequently, the signals from surface-bound and unbound diffusing fluorescent molecules can be obtained simultaneously.
研究领域:
生物物理学
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光学成像
·
分子生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2019
·Vol. 321
·期 1
·161-167
·
IF 1.186
Jiang Min,Xiao Xilin,He Bo,Liu Yong,Hu Nan,Su Changlin,Li Zhiyang,Liao Lifu
In this paper, we report a method for the determination of uranium (VI) based on the using of a surface fluorescence sensor containing a europium (III) complex. The sensor was prepared by immobilizing the Eu(III)-salophen complex on a glass slide surface through Si–O covalent bonds. The sensor can generate strong surface fluorescence as a result of the Cation–Cation Interaction between U (VI) and Eu(III). We used this property to design a surface fluorescence sensing method to detect U (VI). Under suitable conditions, the linear range was 0.02–5 nmol mL −1 and the detection limit was 8 × 10 −3 nmol mL −1 . This method was successfully used in determine U (VI) in real samples with a recovery rate between 99.5 and 103.5%.
研究领域:
分析化学
·
放射化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Xiuqing Li,Hongfen Bian,Siming Yu,Wei Xiao,Jianying Shen,Caifeng Lan,Kenan Zhou,Caihong Huang,Lei Wang,Dan Du,Yuehe Lin,Yong Tang
Using an enzyme-linked immunosorbent assay (ELISA) and limited dilution methods to screen and clone antigen-specific hybridoma cells is extremely time-consuming and labor-intensive. This work features a simple and rapid cell surface fluorescence immunosorbent assay (CSFIA), designed for the detection and isolation of antigen-specific hybridoma clones. In this assay, antigens are first anchored to the hybridoma cell surface through a dual-functioning molecular Oleyl-PEG4000-NHS. Specific antibodies secreted from hybridoma cells are then captured by the antigens on the cell surface. Positive hybridoma cells are stained using a fluorescently labeled anti-mouse IgG-Fc antibody. After the addition of a methylcellulose semisolid medium, positive clones are easily picked using a pipet. These positive cell clones can be used to produce monoclonal antibodies after direct expansion. Using this method, positive hybridoma clones against both malachite green and porcine epidemic diarrhea virus are selected with high efficiency. Compared to the ELISA-based method, the CSFIA-based method achieved the capability of isolating >2-fold more hybridoma clones in <25% of the corresponding processing time. In brief, the CSFIA-based method is highly efficient and inexpensive with a simple and direct operation, which is an excellent candidate method for antigen-specific positive clone isolation in a monoclonal antibody preparation.
研究领域:
免疫学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2019
·
IF 2.994
Jin Tan,Rong Li,Zi-Tao Jiang,Shu-Hua Tang,Ying Wang
To circumvent the limitation of conventional high performance liquid chromatography (HPLC) method, synchronous front-face fluorescence spectroscopy was applied for the rapid and non-destructive determination of two major methylxanthines (theobromine and caffeine) and cocoa solid contents in dark chocolate for the first time. Total synchronous fluorescence spectra at wavelength interval (Δλ) between 30–100 nm of 21 brands of commercial dark chocolate bars with labeled cocoa solids of 50–100% were directly obtained at front-face geometry. The contents of the two methylxanthines were determined by HPLC. Partial least squares regression (PLSR) models for quantification were constructed, optimized, and validated by both full ( leave-one-out ) cross-validation and external validation. The coefficients of determination ( R 2 ) values are larger than 0.8, and the relative errors of prediction were ca. 10%. The built models were applied to the detection of four real samples and compared with HPLC method. The combination of front-face fluorescence and PLSR provides a fast and non-invasive procedure for the quantification of theobromine and caffeine in dark chocolate, as an effective alternative for the traditional HPLC method. The further application of the proposed strategy is the rough estimation of cocoa solids in dark chocolate.
研究领域:
食品科学
·
分析化学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Junmeng Lu,Weiyi Zhang,Xue Zhao,Xinglian Xu
The emulsion abilities of pale, soft, exudative (PSE)-like chicken breast protein are unsatisfied, which are urgently needed to be ameliorated. This study evaluated the improvement of pH-shifting (11.0-, 11.5- and 12.0–7.0) on emulsion properties of the PSE-like chicken breast myofibrillar proteins (MPs) and the underlined structure-driven interfacial mechanism. It was found pH-shifting promoted the exposure of buried hydrophobic groups and free sulfhydryl groups, and changed secondary structures. Emulsions stabilized by refolded MPs exhibited more uniform and dispersed distributions with more adsorbed proteins at the interface. Electrophorogram showed both disulfide and non-disulfide covalent bonds were involved during interfacial protein–protein interaction. The results from circular dichroism and front-surface fluorescence spectroscopy revealed interfacial MPs were exposed to a more hydrophobic environment and increased β-sheets enhanced their molecular interactions. In addition, interfacial proteins after pH-shifting was less likely to be replaced by Tween 20.
研究领域:
食品科学
·
蛋白质化学
·
生物物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）