A DNA microarray (also commonly known as DNA chip or gene chip technology) is a collection of microscopic DNA spots attached to a solid surface. Each DNA spot contains picomoles (10⁻¹² moles) of a specific DNA sequence called probes. Probes are short section of a gene or other DNA element that are used to identify cDNA or cRNA (called gene target) labeled with fluorophore-, silver-, or chemiluminescence which can be quantified for determination of the amount of genes that are transcribed and expressed. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously. The technology can be used to determines how the genes in our cells respond to stimulation like UV light or. It uses a tool called a gene chip to detect the differences in gene expression in old and young skin.

Utilizing this sophisticated tools of genomics, gene chip technology allowed scientists to identify exact pathways that were overly active in the older skin such as (chronic) inflammation. These include pathways that were active in young skin but were inactive in old skin as well as processes and metabolic pathways that were active in older skin but were inactive in young skin. It was discovered that there are large clusters of genes that are differentially regulated and expressed in young versus aging or photodamaged skin. Genes observed in the older skin versus young skin consistently shared certain patterns, including:

• increased expression of Immune and inflammatory response genes
• increased expression of certain extra cellular matrix (ECM) genes in older skin. It appears that photoaging results in more collagen gene changes and chronological skin aging with keratin gene.
• protease/peptidase activity is overexpressed. This leads to over-degradation of skin matrix proteins such as collagen and elastin – the underlying cause of manifestation of signs of skin aging.
• oxidoreductase activity and epidermal development process genes were decreased. This will lead to reduced ability in skin cell proliferation and renewals, and the reduced ability to combat free radical damage.

The most significant theme revealed via gene chip technology , of course, is the inflammatory response observed in chronological aging and photodamaged skin. By understanding how specific genes are modulated by the skin aging process, scientists have been able to tailor treatments to inhibit those processes that are overactive in the aging skin and stimulate those pathways with reduced activity in aging skin, identify ingredients that could positively affect genes involved in the aging mechanism. Through analysis of these pathways at the gene expression level, scientist are making progresses that will ultimately lead to advances in cosmetic anti-aging skin care treatment. The gene chip technology has provided better understanding of skin aging process never before possible which will eventually provide extraordinary potential for improving topical anti-aging skin care formulas.