Microarray bead arrays

There are many protocols and different types of platforms available, e.g. GeneChips from Affymetrix, Illumina Bead Arrays, Arrays from Agilent, Applied Biosystems, GE Healthcare, customized spotted cDNA microarrays etc. the basic procedure for a large-scale measurement of gene expression involves the preparation of total or mRNA from the biological sample(s) under investigation (e.g. candidate tissue) and the hybridization of copied labelled RNA or cDNA to the DNA elements on the array surface (Fig. 1). 

This approach is highly efficient, as thousands to hundreds of thousands or even millions of compounds can be generated easily. In this review, we shall briefly discuss the preparation of these chemical microarrays and follow with a more detailed discussion on the various screening methods. Applications of these microarrays to various biological systems will also be described. The approaches that have been employed for preparing microarrays and the methods used to detect activity in different applications are summarized in Table 1. Schematic representations of the generation of planar chemical arrays and bead-arrays are shown in Figure 1. DNA and... 

Table 2 Planar chemical microarrays vs. OBOC combinatorial library bead-arrays...

Planar chemical microarrays OBOC bead-arrays... 

Another unique approach to microarray technology uses fiber optic bundles to support an array of microbeads that are coated with DNA capture sequences. Each bead is individually associated with a single fiber in the bundle, and hybridization targets labeled with fluorescent dyes are hybridized to the beads. The one-to-one concordance of bead to fiber in the bundle permits every bead in the hybridization array to be addressed and reported individually/94,95)... 

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