Microgenomic technologies enable expression array analysis from extremely limited cell mass. An integrated system of specialized separation techniques, advanced isolation and amplification protocols, and novel quality assurance checks is used in concert to achieve meaningful expression array data from minute samples with confidence. This application note provides a workflow for laser-cut and laser-capture microdissected pure cell populations through to microarray-based expression analysis using state-of-the-art technologies.
Microgenomic technologies provide the tools necessary to examine expression profiles from samples as limited as a single cell. Laser capture microdissection (LCM) is an advanced separation technology that enables the isolation of desired pure cell populations from heterogeneous tissue samples (Veritas Laser Microdissection System, Arcturus Bioscience). LCM utilizes an infrared laser pulse system which adheres cells of interest to a transparent thermoplastic film, preserving essential cellular and morphological characteristics, while maintaining the integrity of biomolecules such as DNA, RNA, and proteins. UV laser cutting (LC) may also be utilized in conjunction with LCM, allowing for the rapid isolation of larger populations of cells, while still maintaining cellular characteristics critical to downstream analyses, such as gene expression profiling. Highly efficient RNA isolation kits and linear amplification kits generate microgram amounts of amplified RNA (aRNA) from minute amounts of total RNA, providing sufficient quantity of probe for microarray analysis. Advances in microspectrophotometry allow quantity and purity assessment at several points during probegeneration.Theretentionsystemofthe NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies) uses surface tension to hold 1L samples in place during