Outline of DNA microarrays

A DNA chip, also called a DNA microarray, is an analytical tool consisting of many DNA fragments densely placed on a resin or glass substrate for detection of changes in expression of genes in samples. DNA microarrays are used in various research areas because they enable exhaustive analysis of several hundred to several hundred thousand genes with a small amount of sample and in a relatively short time. An increasing number of papers registered in PubMed (link) deal with DNA microarrays and DNA chip. Many DNA microarrays, including 3D-Gene®, are used in research aiming toward their practical use in clinical or industrial practice.

Structure of DNA microarrays

General DNA microarrays have a structure in which many types of known DNA fragments for detection are immobilized on a substrate several centimeters on a side. Several tens to several tens of thousands of types of DNA fragments for detection are immobilized on a spot surface and analysis is conducted utilizing hybridization between these DNA fragments and DNA of expressed genes.

Structure of DNA microarrays

Usage of DNA microarrays

Genes extracted from a specimen are labeled fluorescent green, reference standard samples are labeled fluorescent red, and then these are hybridized to a DNA microarray. After the hybridization, the DNA microarray is washed and read by a scanner to detect signals. Examination of the ratio of red signals to green signals after the hybridization reveals which genes are expressed and their expression levels.

Usage of DNA microarrays