Chapter 11 - Protein microarray technologies: An array of applications

Abstract

Microarrays are solid phase-based assay systems consisting of an array of miniaturized test sites arranged in rows and columns. These microspots are usually less than 250μm in diameter. Protein microarray technologies generate an enormous amount of quantitative information with considerable savings in labor and sample volumes. In protein arrays, capture molecules need to be immobilized in a functional state on a solid support. Capture molecules can be printed onto chip surfaces with contact printing arrayers equipped with tiny needles to place sub-nanoliter sample volumes directly onto the surface. Alternatively, non-contact deposition technologies, which employ capillaries or ink jet technology to deposit nanoliter to picoliter droplets onto the surface can be used. Micropatterned protein arrays have also been produced with photolithographic methods. As far as microarray detection is concerned, captured targets are mainly detected by fluorescence using CCD cameras or laser scanners with confocal detection optics. In today's world, microarrays are robust, reliable research tools with which a multitude of parameters can be screened from minimal amounts of sample. The acceptance of protein microarrays, due to the efficiency of sandwich immunoassays, is constantly growing, and they have become useful screening tools in biomarker screening programs, where panels of disease-specific biomarkers are generated.