Microarrays, readout

M. Knauer, N.P. Ivleva, X.J. Liu, R. Niessner, C. Haisch, Surface-enhanced Raman scattering-based label-free microarray readout for the detection of microorganisms. Anal. Chem. 82, 2766 (2010)... 

Moreover, for many of these, the microscopy techniques are not only used for research and development but also for the readout (e.g., confocal microscopes for microarrays) and even for the fabrication (e.g., AFM) of nanoarrays. Also, the continuous miniaturisation of biodevices will eventually reach the desired single molecule detection level—another strong incentive for the general use of advanced microscopy techniques. 

Polycarbonate compact discs have also been used as supports for microarray development [112]. The microarray is generated using an inkjet applicator that employs an electric current to dispense monodisperse droplets containing antibodies onto the disk. The sensing reaction is based on competitive inhibition immunoassays using fluorescent antibodies and final readout is accomplished using a fluorescence scanner. 

Readout of protein microarrays using intrinsic time resolved UV fluorescence for label-free detection. 

After purification of mRNA, it is reverse-transcribed to cDNA, which is labeled with two different fluorescent tags. Equal amounts of cDNA preparation are mixed and applied to die microarray for competitive binding. (B) Most steps for Affymetrix microarrays are similar. For labeling biotin is used and readout of expression values is based on a streptavidin tag binding to biotin. Compared to Agilent, only one sample is hybridized per array. 

Massively parallel analysis or high throughput screening allows the parallel handling of several hundred to up to billions of assays or samples within one run, and performs an according readout for each assay in parallel. Main application examples are microarrays, bead based assays and picowell-plates. 

The basic elements required for the DNA microarray are the solid substrate, the attachment chemistry of the probe to the solid support, the approach adopted to spot the probes at particular locations of the two-dimensional array, the method employed to bring the solution target to the appropriate location of the array (passive or active), and the readout modality. A brief discussion of some of these important elements is given in Sects. 3.2.1-3.2.3. 

Striebel H M, Schellenberg P, Grigaravicius P, et al. (2004). Readout of protein microarrays using intrinsic time resolved UV fluorescence for label-free detection. Pro-teomics. 4 1703-1711. 

Becker, C.F.W., Wacker, R., Bouschen, W., Seidel, R., Kolaric, B., Lang, P., Schroeder, H., Mtiller, 0., Niemeyer, C.M., Spengler, B Goody, R.S., and Engelhard, M. (2005) Direct readout of protein-protein interactions by mass spectrometry from protein-DNA microarrays. Angew. Chem. Int. Ed., 44, 7635-7639. 

Immunoaffinity Extraction on Porous Silicon Microarrays and MALDI MS Readout... 

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