ABSTRACT
I. INTRODUCTION Albeit ill-defined, the terms ‘‘microarray’’ and ‘‘biochip’’ are now widely used in biomedical science in connection with a ubiquitous miniaturized assay technology that permits, in principle, the simultaneous, ultrasensitive, assay of tens, hundreds, or even thousands of substances of biological interest (e.g., DNA fragments, hormones, drugs, etc.) in a small sample (e.g., a drop of blood). Such a ‘‘microarray’’ comprises an array of ‘‘microspots’’ located-in known or identifiable positions-on a solid support,* each microspot comprising a minute area of a specific binding agent (typically an oligonucleotide probe or antibody) that recognizes and binds molecules of an individual target analyte. Although normally present in solution in the sample to which the microarray is exposed, target analytes may also constitute surface components of, for example, cell membranes or other small insoluble cellular structures. Microarray technology is clearly of major importance in medical research and diagnosis, but it is also potentially of value in many other areas, including, for example, the food industry, environmental monitoring, agriculture, forensic investigation, military defense, and so forth.
