Commercial ECL Instruments

At present, MSD Corporation is providing four models of instruments, namely SECTOR Imager 6000, SECTOR Imager 2400, SECTOR PR 400, and SECTOR PR 100 (Fig. 3.7h-i). An ultralow-noise CCD camera is used in SECTOR Imager for light collection with ultimate sensitivity, wide dynamic range, and rapid read 

Ludvik J (2011) DC-electrochemiluminescence (ECL with a cOTeactant)-principle and applications in organic chemistry. J Solid State Electrochem 15(10) 2065-2081. doi 10.1007/ 

Miao W (2007) In Zoski CG (ed) Handbook of electrochemistry. Elsevier, The Netherlands, Amsterdam, p 541 

Fry AJ (1996) In Kissinger PT, Heineman WR (eds) Labtoratory techniques in electroanalytical chemistry, 2nd edn. Deker, New York 

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Abstract The basic components of an ECL instrument consist of supply of an electrical energy for the ECL reaction at an electrode within an electrochemical cell and an optical detector for the measurement of the emitted light intensity. Although certain types of ECL instruments are now commercially available, most of the ECL studies were carried out in homemade ECL instruments according to most of the hterature. A review of some new developments in the ECL instrumentation and ECL cells is described. 

Fig. 3.7 Commercial flow cell-based (a-g) or imaging-based (h-4) ECL instrumentation a ORIGEN 1.5 b M-series M-384 analyzers by BioVeris Corp. 66 c Ml M analyzers by BioVeris Corp. d HcoLumi by Eisai, Japan e Elecsys 1010 f Elecsys 2010 g MODULAR system containing E-170 immunoassay module by Roche Diagnostics 66 h Sector Imager 6000 and i Sector PR Reader 400 by Meso Scale Discovery (Reprinted with permission from Ref. [10]. Copyright 2008 American Chemical Society)...

Figure 13.15 Commercial flow cell-based ECL instrumentation. (A) The ORIGEN 1.5, (B) M series M-384 analyzer by Igen International (now BioVeris, www.bioveris.com), (C) M-1 analyzer by Igen International, (D) PicoLumi by Eisai, Japan, (E) Elecsys 1010, (F) Elecsys 2010, (G) the MODULAR system containing E-170 immunoassay module by Roche Diagnostics (www. roche-diagnostics.com), (H) Sector HTS Imager, and (I) Sector PR Reader by Meso Scale Discovery (meso-scale.com) (modified from reference (133)).

The model immunoassay is the enzyme-linked immunosorbent assay (ELISA) in which a non-specific capture antibody is bound to a surface, such as a multi-well plate or small tube [13]. In the basic form of ELISA, a second antibody tagged with an enzyme interacts specifically with the analyte. The enzyme assay produces a colored product that is read with a spectrophotometer. There are many variations on the basic immunoassay format that serve to increase sensitivity, specificity, linear range, and speed. Many commercial instruments have been developed to take advantage of various technologies for reporter molecules. The immunoassay may be coupled to an electronic sensor and transducer, such as a surface acoustical wave (SAW) sensor. Electrochemiluminescence (ECL) is a method in which the detector antibody is tagged with a ruthenium-containing chelate [13-15]. When the tag is... 

Research in this area addresses the fundamental aspects of energy disposition in fast, very exergonic reactions (3,4), and it serves as a test for theories of electron transfer. By employing ECL-active species as labels on biological molecules, ECL has found application in commercial instruments for immunoassays and DNA analysis. The principles of these methods are outlined in Section 18.1.4. 

Figure 18.1.8 Flow cell used in a commercial instrument for ECL-based immunoassay employing magnetic beads (33-35).

The first co-reactant discovered was oxalate in 1977. The introduction of the co-reactant in ECL exhibits distinct advantage in comparison with the annihilation reaction (1) it can overcome the limited potential window of solvent and the poor stability of radical anions or cations (2) the coreactant ECL can be beneficial for some fluorescent compounds that have only a electrochemical reduction or oxidation (3) the use of co-reactant can produce more intense ECL emission when the annihilation reaction between oxidized and reduced species is not efficient (4) it can eliminate the oxygen quenching effect frequently encountered in ion annihilation reaction and facilitate the ECL in the air. All commercially available ECL analytical instruments are based on this pathway. According to the generated intermediates and the polarity of the applied potential, the corresponding coreactant ECL can be classified as oxidative-reduction ECL and reductive-oxidation ECL, respectively. 

In immunoassays, the antigen or antibody can be modified with biotin and bound to streptavidin-modified magnetic beads. The immunoassay is then carried out with either a Ru complex-labeled antibody or antigen, depending on the chosen immunoassay format (sandwich, competition, or displacement). Commercial instrumentation, available for the detection of DNA or messenger RNA by reverse transcription PCR based on Ru(bpy)3 ECL,... 

In addition, ECL experiments can also be carried out using a commercial fluorescence spectrometer coupled with an electrochemical instrument with the excitation function of the fluorimeter disabled. For example, one can have the three electrodes fitted into a standard fluorescence cuvette so that the entire cell system fits into the sample compartment of the spectrometer. The electrodes should be arranged so that the working electrode faces the detection window of the emission monochromator. ECL intensity can be measured either at... 

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