Beckman-Coulter

Figure Bl.26.7. Diagram of a BET apparatus (representing an OMNISORB 100) (Beckman Coulter 1991 OMNISORP Manual).

Materials required Acetone solution or other polar solutions, standard saline solution of Isoton II, commercial products Multisizer II or 3 (Beckman Coulter Ltd, United Kingdom), Beckman Coulter Ltd or others similar technique. 

FIGURE 4.2 From top left, clockwise hand held i-STAT clinical analyzer and cartridge from Abbott Laboratories, bench top GEM 3000 clinical analyzer from IL, Inc., and large mainframe clinical analyzer UniCel DxC800 from Beckman Coulter, Inc. All these systems utilize ion-selective electrodes to determine clinically relevant electrolytes. 

FIGURE 7.8 Production of reactive oxygen intermediates by activated macrophages. Cells isolated from the livers of control (CTL) or toxicant (TOX)-treated mice were incubated with phorbol myristate acetate for 15 minutes at 37°C, followed by the indicator dye, DCFH-DA. After 15 minutes, the cells were analyzed for green fluorescence by flow cytometry on a Coulter Cytomics FC500 flow cytometer (Beckman Coulter). For each analysis, at least 10,000 events were collected and analyzed using CXP software. 

The first commercial CE instruments were introduced in 1988 by Applied Biosystems (Foster City, CA) and Beckman Coulter (Fullerton, CA). The main challenge during these days was to find out how to overcome poor reproducibility and improve separation efficiency. In the early 1990s, many instrument-building companies introduced CE systems (e.g. Isco (Lincoln, NE), Bio-Rad (Hercules, CA), Waters (Milford, MA), Applied Biosystems, ThermoQuest (Santa Fe, NM) and Dionex (Sunnyvale, CA)), but at the end of the decade only Beckman Coulter... 

Beckman Coulter MDQ General purpose 96-well sampling, numerous detectors... 

FIGURE 4 Comparison of voltage—current behavior between two different instrument models. Neutral capillary, 50 mm i.d. T 20°C, Electrolyte HS a-CD 2% (w/v), 18 crown 6 ether lOmM, methanol 5% (v/v), H3PO4 l5mM, instruments Beckman Coulter P/ACE MDQ and Agilent 3D CE (unpublished). 

Methods development strategy for enantiomer analysis using the P/ACE MDQ chiral system, Application information A-1889A, Beckman coulter, www.beckman-coulter.com... 

A number of commercial antibody-based microarrays for multiplexed cytokines analysis are now available (Beckman Coulter BD Biosciences Panom-ics Pierce S S Zyomyx and others). Cytokines are essentially biomarkers of cell injury, inflammation, and apoptosis. They are released by cells in culture in response to drug action (Turtinen et al., 2004) or are elevated in serum in various disease states. Moreover, numerous cytokines are involved in cellular response and many serve as dual effectors (Asao and Fu, 2000). As a result, anticytokine microarrays are being evaluated in drug discovery for off-target toxicity testing to replace standard ELISA plate formats. 

While Affymetrix s early entry into the DNA microarray market afforded it a formidable position, the company has competitors. In order to commercialize the in situ array, it became clear that access to certain intellectual properties, especially the Southern patent (Oxford Gene Technologies or OGT), was required. Affymetrix obtained a license through a business relationship with Beckman Coulter which originally held the first and exclusive Southern license and later relinquished its exclusivity. Beckman Coulter and Affymetrix entered into a joint venture with Array Automation LLC to automate the processing of Affymetrix chips. Now that license to the Southern technology is available from OGT, others are permitted to commercialize in situ microarrays by alternative chemical S5mthesis approaches. 

A multiplexed immrmoassay has likewise been introduced based upon the ArrayPlate format in which antibody-oligonucleotide conjugates are assembled by hybridization to complementary capture probes. Beckman Coulter introduced the A MicroArray System in March 2004. The A squared or A (array of arrays) approach involves the printing of a capture oligonucleotide "zip code" in the bottom of a rounded square 96-well... 

Novagen (ProteoPlex ), S S (FAST Quant), BioSource (Cartesian Array ), and BD Biosciences (BD Clontech Ab Microarrays) have introduced or will soon introduce protein microarray slide formatted products in which antibodies are directly immobilized. Beckman Coulter s protein array products for performing micro-ELlSAS in standard 96-well plate formats are based upon the self-assembly (by hybridization) of oligonucleotide-antibody conjugates to complementary oligonucleotides arrayed in individual wells. HTG s protein array technology was described previously. 

Aroxmd the same time, Beckman Instruments (now Beckman Coulter) had begun an array-based product development program focused on the use of modified plastics. Silzel and coworkers (1998) and Matson et al. (2001) of Beckman Coulter were among the first to pursue printing of antibodies onto a plastic surface in a microarray format. Silzel et al. immobilized biotinylated monoclonal antibodies onto an avidin-coated polystyrene surface and performed micro-ELISA-based isotyping of IgG species. Matson et al. 

Others such as Macas et al. (1998) successfully adapted the Biomek 2000 (Beckman Coulter), a commonly used liquid handling robot, to prepare microarray slides using a specially constructed print head and quill pins. Up to 28 microscope slides could be placed on a work surface for printing. Biomek s HDRT head was adapted to accept microarray quill pins held between two parallel plates with holes drilled on 9-mm centers to dip into 96-well source plates. The quill pins were spring-loaded similar to the design... 

This author and coworkers at Beckman Coulter first described the use of a low form 96-well plastic microplate for automated micro-ELISA immunoassays (Matson et al., 2001). The polypropylene plate was first modified by a radiofrequency plasma amination process (Matson et al., 1995) followed by conversion to an acyl fluoride surface chemistry for rapid covalent attachment of biomolecules. Proteins (1 to 2 mg/mL) were prepared in 50 mM carbonate buffer, pH 9, containing 4% sodium sulfate (to improve spot uniformity) and printed using a conventional arrayer system. Approximately 200-pL droplets of monoclonal antibodies (anti-cytokine) were deposited into the bottom of the microwells using a Cartesian PS7200 system equipped... 

An altemahve approach is the "mass-sensing" multianalyte microarray immunoassay first described by researchers at Beckman Coulter, Fullerton, CA (Silzel et al., 1998). As early as 1991, other groups at Beckman Coulter had adapted commercially available ink-jet printers (e.g., the Hewlett Packard Deskjet) for deposihng oligonucleohdes or proteins such as streptavidin onto substrates to create arrays (Matson, xmpublished data). Piezoelectric... 

The protein microarray represents an emerging technology. While we have described its potential utility, several key problems remain to be overcome before this tool is fully adopted by the research and biopharmaceutical commxmities. The most likely first embodiment will be an antibody "protein-detecting" microarray. This is understandable based upon the availability and suitability of antibody libraries originally developed for ELISA. We have discussed many demonstrahons of antibody arrays in this chapter but commercial introductions (Pierce, Beckman Coulter) have been limited. 

Robert (Bob) Matson, Ph.D., is a senior staff scientist in the Advanced Technology Center at Beckman Coulter, Inc., Fullerton, California. He has been involved in the development of both nucleic acid and protein array-based technology for the past 13 years. His initial introduction to array technology began in collaboration with Sir Edwin Southern in developing an in situ oligonucleotide array synthesis platform for the corporation. Later work by Dr. Matson and his research team produced some of the first plastic microplate-based microarrays. Beckman Coulter recently launched the pi te based upon the microplate "array of arrays" concept. 

Prior to joining Beckman Coulter, he served in several technical management roles including R D director at BioProbe International, R D director at Costar-Nuclepore, and R D group leader, chemistry, at BioRad Laboratories. 

The siRNA libraries are obtained as a 10 pM stock and we prepare a 1 30 dilution resulting in 333 nM daughter plate concentrations. Although this step can be done manually using multichannel pipets, it can be greatly expedited by the use of a liquid-handling system, such as the Biomek EX Workstation (Beckman Coulter Brea, CA). 

Fig. 5.2. rpm-g graph for fixed-angle (type 45 Ti) and swinging-bucket (SW 28) Beckman Coulter ultracentrifuge rotor... 

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