In the past couple of decades, the mass spectrometer has moved out of its original domain in the chemistry lab to become an important tool for the biological sciences. The original technology has been adapted to a wide array of biological compounds and is now used routinely for genomic and proteomic applications. New studies suggest that the technique may be on the cusp of another great leap forward, according to a study published in the October 15 issue of Science by a group of researchers at Purdue University.

The study describes a new mass spectrometry ionization method called DESI - desorption electrospray ionization - which seems poised to springboard mass spectrometry (MS) to wider markets and even perhaps the consumer market.

Sample preparation has long been the limiting factor for MS analysis. Generally, samples are mixed with a matrix and ionized in a vacuum by laser ablation, or they are ionized under atmospheric conditions by an ion spray. Once ionized, the molecules are identified by their charge-to-mass ratio. Both procedures require complicated methods of sample preparation, making them unsuitable for application in the field.

DESI obviates sample preparation by ionizing the sample directly off a surface with a stream of solvent, under ambient temperature and pressure. The ionized sample is then sucked into the mass spectrometer and analyzed. The method works for a variety of compounds - including peptides and proteins - present on metal, mineral, or polymer surfaces, as well as small organic molecules.

In the Science paper, the Purdue group shows that they could detect an antihistamine on the skin of a person who had taken a pill 40 minutes earlier, and even traces of the explosive RDX present on a leather surface.

The potential applications of the new technology are numerous, including environmental screening, point-of-care applications in healthcare, and for homeland defense and safety screening. According to John Hurrell, president of Inproteo LLC, an Indiana-based venture aiming to commercialize DESI, applications also exist in the food industry and in online process control for manufacturing of pharmaceuticals. Discussions are under way with major diagnostics companies and manufacturers of MS equipment.

HUPO Offerings

Other advances in the area of MS technology were announced in October at the 2004 Human Proteome Organisation (HUPO) Conference, held in Beijing. Bruker Daltonics announced the Prespotted AnchorChip, a disposable AnchorChip MALDI (matrix-assisted laser desorption/ionization) target for gel-based and LC-MALDI-based expression proteomics, also aimed at facilitating sample preparation.

The Prespotted AnchorChip is available in a 384-sample microtiter plate format - and includes an additional 96 calibrant spots that have all been pre-spotted with matrix. Each chip is packaged under inert gas in a container that can also be used for sample archiving after the analysis. The Prespotted matrix and the calibrant spots are designed such that users can apply aqueous peptide and protein digest samples directly to the target for analysis. Each chip has individual bar codes to facilitate sample tracking.

According to Michael Schubert, vice president for R&D at Bruker Daltonics, the new disposable format is crucial for high-throughput validation and comparison studies in the pharmaceutical industry because it reduces the problem of cross-contamination and makes MALDI sample preparation simpler and less labor intensive.

Bruker also unveiled the ultraflex II, a MALDI-TOF and TOF/TOF mass spectrometer that the company says offers further advances in the sensitivity, resolution, and mass accuracy of TOF/TOF systems. The new machine is aimed at expression proteomics, quantitative proteomics, and biomarker discovery. The ultraflex II can be used for peptide de novo sequencing, the analysis of post-translational modifications, and even top-down protein primary structure determination. (Details of the Prespotted AnchorChip and the ultraflex II can be found at http://www.bdal.com.)

Robert M. Frederickson is a biotech writer based in Seattle.

Automated Gel Casting

NextGen Sciences noticed that many researchers are moving toward larger gel formats to increase resolution, but pouring gradient gels by hand leads to considerable variability. Also, large pre-cast gels are expensive, have short shelf lives, and are available with a limited choice of gradients. So the company developed the a2DEoptimizer, a system to automate gel casting to user-friendly gradients, for improving manual 2D electrophoresis by increasing reproducibility and enhancing the resolution of protein separations. The a2DEoptimizer allows researchers to create customized gradient gel profiles, and once the profiles are stored in the computer, the gels can be cast automatically by the system, giving the same result every time that profile is recalled. The benchtop system can be used with a wide range of commercially available flatbed IEF units and 2nd dimension gel tanks, is supplied with ready-to-use reagents, and uses traditional gel chemistries referenced in thousands of publications.

Vendor: NextGen Sciences

Product: a2DEoptimzer

Availability: Now

For more information: +44(0) 1480 420 974; www.nextgensciences.com

RNA Amplification System

NuGEN Technologies has introduced the third product in its Ovation family of RNA amplification and labeling kits for gene expression research. The Ovation RNA Amplification System achieves 10,000-fold amplification and creates sufficient cDNA product to perform up to 250 qPCR reactions while maintaining the relative abundance of the gene transcripts during amplification. Use of the system prior to qPCR analysis amplifies mRNA in potentially limited, biologically relevant samples, such as small biopsies or flow-sorted cells, giving researchers the ability to analyze gene transcripts of interest as well as save additional material for future reference.

Vendor: NuGEN Technologies

Product: Ovation RNA Amplification System

Availability: Now

For more information: (650) 590-3600; www.nugentechnologies.com

RNA Isolation

Agencourt Bioscience has expanded its reagents product line with the release of a kit for RNA isolation and purification. The RNAPrep kit is optimized for isolating total RNA from eukaryotic cultured cells and leverages the company's SPRI (Solid Phase Reversible Immobilization) magnetic bead technology. The kit method has been formatted to work in single tubes through fully automated plate formats with streamlined processing times of under 20 minutes. The company says that RNAPrep explicitly addresses the need for automated isolation of high-quality RNA for downstream applications, such as gene-expression analysis.

Vendor: Agencourt Bioscience

Product: RNAPrep Kit

Availability: Now

For more information: (978) 867-2600; www.agencourt.com

Contact Printing Kits

Contact Printing Kits-in-a-Bag by Platypus Technologies allow researchers to transfer a chemical or biological agent from a low-energy surface, such as PDMS, to a high-energy surface, such as gold or plain glass, through contact. Each kit includes the user's choice of three PDMS stamps; printing surfaces; and thiols to functionalize printing surfaces. Contact Printing Kits-in-a-Bag are useful for scientists to print biological molecules, such as proteins, onto a high-energy surface; to micro-pattern or nano-pattern chemicals onto a surface; to pattern self-assembled monolayers (SAMs); and to print molecules such as synthetic receptors, oligonucleotides, synthetic ligands, peptides, proteins, antibodies, viruses, or carbohydrates onto thiol SAMs.

Vendor: Platypus Technologies

Product: Printing Kits-in-a-Bag

Availability: Now

For more information: (866) 296-4455; www.platypustech.com

LIMS for Genomics and Proteomics

Applied Biosystems' new LS*LIMS software is a new workflow management and process automation solution that ABI says increases productivity, improves data quality, and integrates data from many different sources for genomics and proteomics laboratories. The LS*LIMS software provides a drag-and-drop workflow editor to map and automate bench lab operations, and the development tool kit allows researchers to customize in silico activities. The software's open architecture lets customers configure the system to meet the needs of large or small labs and provides a common user experience across Applied Biosystems instruments and applications.

Vendor: Applied Biosystems

Product: LS*LIMS Software

Availability: Now

For more information: (650) 570-6667; www.appliedbiosystems.com