ECL Instrumentation

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. 

Keywords Nonaqueous electrochemical media Electrochemiluminescent cell Lab on a chip Light detection Charged coupled device cameras 

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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)...

Several immunoassays can now be performed with imaging-based ECL instruments manufactured by Meso Scale Discovery (Chap. 3, Fig. 3.7) [22, 23]. Approximately 150 immunoassays are currently available from this company. These include phosphoprotein and intracellular markers, cardiac markers, vascular markers and growth factors, fertility markers, Alzheimer s disease markers, hypoxia markers, toxicology, metabolic markers, bone markers, bioprocess assays, and cytokine and chemokine immunoassays. Further description and discussion on the particular immunoassays of interest may be found in Ref. [22]. 

Combination of assembled microcell [134] or Au chip electrode [132] with a positive-intrinsic-negative (PIN) photodiode detector lead to advancement in the miniaturization of ECL instrumentation for DNA quantification. Though, noise level and sensitivity of sihcon PIN diode are less sensitive than a PMT [134]. A highly sensitive DNA biosensor, fabricated by self-assembling the ECL probe of thiolated hairpin DNA tagged with ruthenium complex on the surface of a gold electrode works on a switch-off mode and ECL intensity decreases with an increase of the concentration of target DNA, and a detection limit of 9 x 10 M... 

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 basic components of a home-made ECL instrument for ECL intensity measurement generally consist of a potentiostat, an electrochemical ceU, a light detector, and a data acquisition system. Many recently produced computer-based potentiostats, such as CH660A (CH Instruments, Austin, Texas, www.chinstruments.com). Autolab PGSTATIOO (Autolab Electrochemical Instruments, the Netherlands, www.ecochemie.nl), have external signal... 

Figure 13.17 Schematic diagram of an ECL instrumental setup, (for colour version see colour section at the end of the book).

Since the first report on the CL of RnCbpylj " with aliphatic amines (21), followed by the ECL stndy of the Ru(bpy)3 + with TPrA as a coreactant (20), a wide range of ECL fundamental research and analytical apphcations involving Ru(bpy)3 or its derivatives have been reported (8). The Rn(bpy)3 + (or its derivatives) with TPrA exhibit the highest ECL efficiency, and the relevant experiments can be carried ont in an aqueous solution with a relatively wide range of pH (Fignre 13.5) in the presence of oxygen. Consequently, this system is well snitable for ECL demonstrations (174,175), as well as for ECL instrumental setup examinations. 

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