Cast Array

Microarrays, or "gene chips," have become valuable tools for studying changes in gene expression; detecting genetic mutations and polymorphisms; analyzing drug resistance and disease susceptibility; and sequencing unknown DNA. The microarray, which consists of cloned genes, PCR products, or synthetic oligonucleotides immobilized on a microscope slide, is analyzed by hybridization with target DNA or RNA that is labeled with radioisotopes or fluorescent dyes.1 For example, total mRNA isolated from

Apr 30, 2001
Hillary Sussman
Microarrays, or "gene chips," have become valuable tools for studying changes in gene expression; detecting genetic mutations and polymorphisms; analyzing drug resistance and disease susceptibility; and sequencing unknown DNA. The microarray, which consists of cloned genes, PCR products, or synthetic oligonucleotides immobilized on a microscope slide, is analyzed by hybridization with target DNA or RNA that is labeled with radioisotopes or fluorescent dyes.1 For example, total mRNA isolated from two different cell populations and reverse transcribed into cDNA with two different fluorescent labels can be hybridized with an array of known DNA sequences. The fluorescence for each dye is measured separately to determine the relative abundance of each specific transcript in the two samples.

Unfortunately, many laboratories do not have access to this technology because computer-controlled robots that generate high-density arrays are very expensive. The new MicroCASTer from Schleicher & Schuell Inc. of Keene, N.H., is an economical, 8-pin, hand-held arrayer that uses free-floating micro-slotted pins to transfer samples from 96-well source plates to nylon membrane-coated glass slides, depositing 500 µm spots. Up to 768 spots can be placed in under 20 minutes, and a special index system allows preparation of duplicate slides with excellent reproducibility. Breck Parker, senior scientist at S & S, helped to design the MicroCASTer so that it would be "quick, simple, and economically convenient ... for someone who couldn't [previously] access the technology or for [the researcher] who only wanted to array a few samples without queuing for and programming the robotic arrayer."

Also available to complement the MicoCASTer is the CAST™ Slides Microhybridization Kit. Along with optimized prehybridization and hybridization buffers, this kit includes unique hybridization chambers which allow superior mixing of solutions compared with regular glass coverslips, thereby reducing cross-hybridization and promoting a greater level of specificity.

-Hillary E. Sussman (hes01@health.state.ny.us)
1. B. Sinclair, "Everything's great when it sits on a chip," The Scientist, 13[11]:18, May 24, 1999.

For More Information
Schleicher & Schuell Inc.
(800) 245-4024
www.arraying.com