Nephelometric assay of immunoglobulin G chemically bound to chloromethyl styrene beads

Monodisperse core–shell stable latexes with reactive methylchloride surface functionalities were prepared at two different reaction temperatures. The reaction temperature played an important role in the amount of reactive functional groups. The covalent coupling had an efficiency of more than 50%. Antibodies covalently bound to functionalized polystyrene beads were used to detect corresponding antigens by nephelometry.     

荧光素类荧光分子探针

荧光素衍生物是重要的荧光探针,在检测和生物成像等领域中显示出巨大的前景。因此,急需对功能性荧光素结构探针的设计策略进行深入研究。通常通过引入醛基或酯化到荧光素呫吨环和苯部分来构建探针,由于其高活性,这些衍生物可以与分析物复合以发生颜色和荧光强度的变化。本文总结了荧光素的修饰位点及方法,介绍了荧光素探针的合成、性质及应用,并对近五年荧光素探针对不同分析物(包括金属阳离子、阴离子、小分子和生物大分子)的检测进行分类说明,旨在为高灵敏度荧光素探针的筛选和生物检测提供参考,并推动其在分析物传感和检测中的进一步应用。     

Advancing the Drug Discovery and Development Process

The current state of affairs in the drug discovery and development process is briefly summarized and then ways to take advantage of the ever‐increasing fundamental knowledge and technical knowhow in chemistry and biology and related disciplines are discussed. The primary motivation of this Essay is to celebrate the great achievements of chemistry, biology, and medicine and to inform and inspire students and academics to enter the field of drug discovery and development while, at the same time, continue to advance the fundamentals of their disciplines. It is also meant to encourage and catalyze multidisciplinary partnerships between academia and industry as scientists attempt to merge their often complementary interests and expertise to achieve new improvements and breakthroughs in their respective fields, and the common goal of applying them to the discovery and invention of new and better medicines, especially in areas of unmet needs.     

A simple kinetic model of antigen-antibody reactions in particle-enhanced light scattering immunoassays

Polymer colloids coated by antibodies are used in diagnostic tests for the detection of antigens in biological fluids. We present in this paper a simple kinetic model for the optical monitoring of the formation of specific complexes between antigen and antibody with amplification by latex beads. The antibodies are physical or chemically adsorbed onto sulphonate polystyrene or chloromethylstyrene particles respectively. This is a very simple model combining the La Mer idea of optimum surface coverage with Langmuir adsorption of antigen molecules. The kinetic model explains reasonably well the optical response of immunolatex prepared by both methods of immobilization of antibodies on polymer carriers. According to the results obtained with this model the percentage of active IgG on latex particles is extremely low, with a maximum of a 5%.     

Tuning a Bisphenol A Lateral Flow Assay Using Multiple Gold Nanosystems

Advanced bisphenol A (BPA) lateral flow assays (LFAs) that use multiple nanosystems are reported. The assays use three nanosystems: gold nanostars, gold nanocubes, and gold nanorods, which are rarely applied in LFAs, compared with general gold nanoparticles that are referred to as gold nanospheres in this paper. These various nanosystems are bound to anti‐BPA antibodies and applied in LFAs to develop advanced BPA LFAs; the developed LFAs show differing BPA detection performance, as well as different visible colors, optical intensities, limits of detection, and application ranges. Advanced BPA LFAs that use multiple gold nano‐object shapes are successfully developed, and the geometry effects of diverse gold nanosystems coupled with anti‐BPA antibodies and the potential applications of regular BPA LFAs are explored.     

A Fluorescence‐Based Supramolecular Tandem Assay for Monitoring Lysine Methyltransferase Activity in Homogeneous Solution

The demand for practical and convenient enzyme assays for histone lysine methyltransferases (HKMTs) emerges along with the rapid development of this young class of enzymes. A supramolecular reporter pair composed of p‐sulfonatocalix[4]arene (CX4) and the fluorescent dye lucigenin (LCG) has been used to monitor enzymatic trimethylation of lysine residues in peptide substrates. The assay affords a switch‐ON fluorescence response and operates in a continuous, real‐time, and label‐free fashion. The underlying working principle relies on the higher affinity of the macrocycle towards the trimethylated product of the enzymatic reaction as compared to the substrate, which allows the assay to be carried out in the product‐selective mode. The final product incorporates a trimethylammonium moiety, a known high‐affinity binding motif for CX4. Two substrates corresponding to the H3 N‐terminal tail, namely, S2 (RTKQTA RKSTG GKAP) and S6 (QTA RKSTG GS), were selected as model compounds for methylation with the Neurospora crassa Dim‐5 enzyme and investigated by the newly developed supramolecular tandem HKMTs assay. Only the longer substrate S2 underwent methylation in solution. The potential of the assay for inhibitor screening was demonstrated by means of inhibition studies with 1,10‐phenanthroline to afford an inhibition constant of (70±20) μM .     

SERS active Ag nanoparticles in mesoporous silicon: detection of organic molecules and peptide–antibody assays

Ag nanoparticles synthesized on porous silicon samples were studied and applied as substrates for surface‐enhanced Raman scattering (SERS). The metallic nanostructures prepared by immersion plating were characterized by UV–Vis reflectance spectroscopy and scanning electron microscopy. SERS activity of the substrates was tested using Cyanine dye 1,3,3,1′,3′,3′‐esamethyl‐5,5′‐dimethoxyindodicarbocyanine iodide (Cy5‐OCH₃) as a probe molecule. The Raman spectra obtained for different excitation wavelengths indicate amplifications ascribed to plasmonic resonances with an enhancement factor up to 10⁷. CGIYRLRS peptides were chemisorbed on the Ag nanoparticles with the plasmonic resonance tuned at the excitation energy. Such oligopeptides were used as baits for a specific polyclonal antibody. The overall Raman enhancement allowed to evidence a good selectivity to the target analyte as required by most of the SERS applications on biological assays. Copyright © 2011 John Wiley & Sons, Ltd.     

Polysulfone/pyrene membranes: a new microwell assay platform for bioapplications

The use of PSU‐Py prepared by click chemistry as a platform in membrane‐bottom microwell plates for oxidase and hydrolase/oxidase‐based enzyme assays is studied. For the GOx assay, the postulated fluorescence mechanism is based on the consumption of glucose by dissolved oxygen and GOx in the microwell plates covered with the PSU‐Py membrane. For the AG‐GOx assay, maltose is used as AG substrate and hydrolyzed to glucose which is then oxidized by the GOx activity. It is shown that the PSU‐Py membrane acts as a fluorescence indicator of the enzymatic reactions, and both GOx and AG/GOx enzyme assays are successfully applied for glucose, maltose and acorbose analysis in the range 0.125–2.0 × 10^?3 M glucose, 0.05–0.5 × 10^?3 M maltose, and 0.0125–0.1 mg · mL^?1 acorbose, respectively.