Microplate imager

Zeiss have developed a high-throughput reader system (the Plate Vision multimode reader) for microwell plates that is capable of fast time-resolved fluorescence (Fast-TRF) imaging with nanosecond resolution [ 189] (Fig. 28), which has found applications in pharmaceutical screening. This microplate imager is suitable for time-resolved RET assays. Kinase assays, for instance, can be performed with antibodies labeled with a Ru(batho)2bipy complex or... 

Fig. 16 Fluorescence images of LIVE/DEAD assays of the L929 cells encapsulated for 4 days (a) in the miniaturized PMBV/PVA hydrogel formed in the microfluidic chip, and (b) in the bulk PMBV/PVA hydrogel formed in the 96-well microplate. Green fluorescence indicates live cells and red fluorescence indicates dead cells. Scale bar 100 pm...

A new suspension array concept based on sedimentation and microscopic imaging was introduced by Moser et al. [98], Magnetic microbeads settle to the bottom of a microplate well by magnetic forces and form randomly ordered arrays, which are examined by fluorescence microscopy and automated imaging analysis. Each bead carries specific capture molecules and can be identified by a defined luminescent code. 

The method may also be used the other way round with GOx as the enzyme label, glucose as substrate, and [Eu(Tc)] as the fluorescent indicator. In that type of assay, the presence of enzyme-labeled antibodies is indicated by an increase in the observed fluorescence intensity. It should be noted that commercially available fluorescence microplate readers, preferable equipped with time resolution, are also suited for the screening of all the microwell plate-based assays presented in this chapter. Nevertheless, the imaging process is much faster, accomplished in the order of one second, and enables ratiometric measurements. 

After 5 min, the time necessary to obtain a steady state of the enzymatic reaction, photon emission from the microplate is measured with the CCD camera using the same setting (i.e., height of the camera, integration time, binning) adopted for mouse imaging acquisition. 

Fig. 10.10 Selective fluorescence responses of the ATP and GTP sensors. Experiment was conducted on a microplate for fluorescent ATP and GTP-binding RNPs generated by mixing 7mC-Rev (lpM) and the RNA subunits (1 pM) of ATP-binding RNP (A01, A14, A23, A32, and A34) and GTP-binding RNP (G08, G23, G10, G16, and G05) in the presence of 0.1 mM ATP, UIP, CTP, or GTP. Lanes marked pep and blank contained 7mC-Rev and only a reaction buffer, respectively. Fluorescence intensities of samples were measured with excitation at 355 nm and emission 390nm. Images of the fluorescence intensity of wells were shown with intensities being weak in black color and strong in white...

Fig. 5 An actual resonant band image of 5 rows of 7 sensors in a 96-well sensor microplate containing living cells obtained using the arrayed angular interrogation system. The broken circle indicated that the cell density was not even across this specific sensor, which was confirmed by light microscope imaging (Reproduced with permission from ref. [18])...

Multimode CCD image detection (UV/Vis, TRF, TR-FRET luminescence, fluorescence) simultaneously from all wells of a microplate... 

Microplate reader/imager, e.g., PHERAstar (BMG Labtech), Envision (Perkin Elmer), ViewLux (Perkin Elmer). 

Hendrickson O. D., Warnmark-Surugiu I., Sitdikov R., Zherdev A. V., Dzantiev B. B., and Danielsson B., Development of microformat imaging microplate and membrane immunoenzyme assays of the herbicide atrazine, Int. J. Environ. Anal. Chem., 85(12-13), 905-915, 2005. 

Optical spectroscopy requires either spectrophotometers, to measure absorbance, fluorimeters, to measure fluorescence, or microscopes, which can measure fluorescence or absorbance of single cells or small groups of cells. Fluorimeters and spectrophotometers usually require solutions or suspensions of material in conventional cuvettes microscopes provide two-dimensional images from smears, slices or siufaces. Other devices that record signals resolved in two-dimensions include gel scanners and microplate readers. Essentially these devices sample the object in an organized manner (detectors can be set up to record absorbance or fluorescence) and information is stored in an electronic array that maps precisely the physical layout of the original object. 

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