Capillary electrophoresis with laser-induced fluorescence detection as a tool for enzyme characterization and inhibitor screening

Single-step Trypsin Inhibitor Assay on a Microchannel Array Device Immobilizing Enzymes and Fluorescent Substrates by Inkjet Printing

In this paper, we report a single-step trypsin inhibitor assay on a microchannel array device immobilizing enzymes and substrates by inkjet printing. The microdevice is composed of a poly(dimethylsiloxane) (PDMS) microchannel array that immobilizes trypsin and fluorescent substrates as reactive reagents at the two bottom corners of a microchannel. Inkjet printers allow simple, accurate, and position-selective immobilization of reagents as nanoliter spots. Therefore, plural reactive reagents, such as enzymes and substrates, can be separately immobilized at different positions in the same microchannel without mixing, and thus allowing for single-step operation by simply introducing a sample solution through capillary action. Furthermore, reproducible fabrication and mass production of the device could be expected. In this study, the efficiency of an acidic solution as a spotting agent for protease immobilization to prevent decrease in the fluorescence intensity was confirmed. Additionally, single-step trypsin inhibitor screening was performed using three inhibitors. Finally, we investigated the storage stability of the device and confirmed that it remained stable for at least 10 days.

Application of Capillary Electrophoresis with Laser-Induced Fluorescence to Immunoassays and Enzyme Assays

Capillary electrophoresis using laser-induced fluorescence detection (CE-LIF) is one of the most sensitive separation tools among electrical separation methods. The use of CE-LIF in immunoassays and enzyme assays has gained a reputation in recent years for its high detection sensitivity, short analysis time, and accurate quantification. Immunoassays are bioassay platforms that rely on binding reactions between an antigen (analyte) and a specific antibody. Enzyme assays measure enzymatic activity through quantitative analysis of substrates and products by the reaction of enzymes in purified enzyme or cell systems. These two category analyses play an important role in the context of biopharmaceutical analysis, clinical therapy, drug discovery, and diagnosis analysis. This review discusses the expanding portfolio of immune and enzyme assays using CE-LIF and focuses on the advantages and disadvantages of these methods over the ten years of existing technology since 2008.

Matching the power of high throughput screening to the chemical diversity of natural products

Covering up to 2013. Application of high throughput screening technologies to natural product samples demands alterations in assay design as well as sample preparation in order to yield meaningful hit structures at the end of the campaign.

Advances in capillary electrophoretic enzyme assays

In recent years, capillary electrophoresis (CE) has become a frequently used tool for enzyme assays due to its well-recognized advantages such as high separation efficiency, short analysis time, small sample and chemicals consumption. The published applications cover all aspects of enzyme characterization and analysis including the determination of the enzyme activity, substrate and modulator characterization and identification, as well as the investigation of enzyme-mediated metabolic pathways of bioactive molecules. The CE assays may be classified into two general categories: (1) pre-capillary assays where the reactions are performed offline followed by CE analysis of the substrates and products and (2) online assays when the enzyme reaction and separation of the analytes are performed in the same capillary. In online assays, the enzyme may be either immobilized or in solution. The latter is also referred to as electrophoretically mediated microanalysis (EMMA). The present review will highlight the literature of CE-based enzyme assays from 2006 to November 2009. One section will be devoted to applications of microfluidic devices.