By Michael J. Miller, Ph.D., Senior Research Fellow, Eli Lilly and Co. Microarrays are collections of miniaturized test sites, arranged on solid substrates, that permit many tests to be performed at the same time. They are composed of an orderly arrangement of protein or thousands of DNA or RNA fragments on glass, silicon or nylon substrates. This technology evolved from Southern Blotting technology, in which fragmented DNA is attached to a substrate and then probed with a known gene or DNA fragment, using fluorescent tags to allow visual detection. Microarrays are usually fabricated using a variety of technologies, including printing with fine-pointed pins onto glass slides, photolithography, ink-jet printing or electrochemistry. Other methods may also be used, such as in situ synthesis, whereby the probes are synthesized directly on the chip instead of spotting them on the array. An example would be CombiMatrixs (Mukilteo, Wash.) CustomArray. Applications for microarrays include nucleic acid sequence identification and measuring expression levels of genes. For example, Affymetrixs (Santa Clara, Calif.) GeneChip contains the entire human genome (~50,000 known genes and gene variants) on a single chip, while CombiMatrixs CustomArray contains probes that can detect influenza A and Avian H5N1 (bird flu) strains. Both of these platforms are commercially available. A biosensor can detect an analyte that is comprised of a biological component combined with a physicochemical detector component. Nineteenth-century miners used a canary in a cage as a biosensor to detect lethal concentrations of gas. Today, the most widespread example of a commercially available biosensor is the blood glucose monitor, but future uses will include remote sensing of airborne bacteria and detection of pathogens. The biological component of a biosensor may contain tissue, microorganisms, organelles, cell receptors, enzymes, antibodies, nucleic acids or whole cells. The detector element works in a physicochemical manner and may include
Products & Services
Microarray Scanners are used to perform microarray analysis by acquiring images of laser induced fluorescence.
Biosensors and Microarrays
Biosensors, microarrays, biochips and lab-on-chip (LOC) products are microscale devices for biological, biochemical and chemical arrays. They consist of microfluidic channels and a biodetector or microsensor arrays.
Lab-on-a-Chip (LOC) Devices
Lab-on-a-chip (LOC) devices are integrated semiconductors that serve as a laboratory for the testing and analysis of very small chemical and clinical samples.
DNA sequencers are used to automate the DNA sequencing process.
Gel Electrophoresis Equipment
Gel electrophoresis equipment, instruments and supplies are used to separate macromolecules, either nucleic acids or proteins, on the basis of size, electric charge, and other physical properties.
Topics of Interest
Electrochemical detection for microarray IVD applications Alternative methods offer advantages over traditional fluorescence. Amit Kumar and Kilian Dill Microarrays can analyze large numbers of...
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Using 4-D diagnostic tools for genetic analysis 4-D microarrays offer a number of advantages compared with traditional 2-D arrays. Mridula Iyer, Reena Philip, Hoyt E. Matthai, Eric Eastman, and Andrew...
By Michael J. Miller, Ph.D., Senior Research Fellow, Eli Lilly and Co. use viability stains and/or cellular markers to detect and quantify microorganisms without the need for cellular growth.