- Microarrays are powerful analytical tools used to simultaneously measure the expression levels, presence, or interactions of thousands of biological molecules—most commonly nucleic acids or proteins—on a single, miniaturized platform.
- The underlying principle involves the immobilization of specific capture probes (such as DNA oligonucleotides, cDNA fragments, or antibodies) onto a solid surface, typically a glass slide, silicon chip, or membrane, arranged in an orderly grid format. Each spot on the array represents a unique sequence or target molecule, enabling highly parallel detection and analysis.
- In the context of DNA microarrays, which are among the most widely used types, the goal is to assess gene expression or detect genetic variations. The array is hybridized with fluorescently labeled nucleic acids—usually complementary DNA (cDNA) or RNA—extracted from a sample. If the sample nucleic acids contain sequences complementary to the immobilized probes, hybridization occurs. After washing to remove unbound material, the array is scanned with a laser, and the fluorescence intensity at each spot corresponds to the abundance of the target sequence in the sample.
- Protein microarrays operate on similar principles, but instead of nucleic acid hybridization, they rely on antigen-antibody or protein-ligand interactions. These are used to study protein expression, enzyme activity, post-translational modifications, or antibody profiling. Protein arrays are more challenging to develop due to the need to maintain protein structure and function after immobilization, but they provide unique insights into the functional proteome.
- Microarrays have revolutionized molecular biology and genomics by enabling large-scale, rapid, and multiplexed analyses. They are widely used in applications such as disease diagnostics, pharmacogenomics, toxicogenomics, biomarker discovery, and cancer classification. The data generated from microarray experiments are rich and complex, often requiring bioinformatics tools for normalization, pattern recognition, and interpretation.
- Despite the emergence of next-generation sequencing (NGS) technologies, microarrays remain valuable due to their cost-effectiveness, speed, and suitability for routine applications where known targets are being studied. Their continued development and integration with other platforms underscore their importance in high-throughput molecular research.
