Peptide chips for improved cancer diagnostics
Short synthetic protein fragments, i.e. peptides, are an important tool for researchers and medics. However, peptide production is expensive and time-consuming. Scientists at the German Cancer Research Centre (DKFZ) have now succeeded in generating peptides on a microchip – faster and thus cheaper than with previous methods.
Synthetic peptides are indispensable for numerous biochemical and diagnostic detection processes, including the detection of antibodies that enable scientists to diagnose diseases. Dr. Volker Stadler, Dr. Ralf Bischoff and Dr. Frank Breitling have developed a new method to generate peptides directly on a microchip. The method is very efficient: while conventional peptide chips yield a density of 22 peptides per square centimeter, the new DKFZ microchip delivers 40,000 different peptides per square centimeter.
If magnified many times, the microchip looks like a giant chessboard. The protein fragments are assembled on the squares step by step from their building blocks, the 20 amino acids. It is possible to select a different sequence of these building blocks on each square. To start with, the amino acids are integrated into solid pellets. Electrical fields direct the pellets to the right place on the chip. When there are matching amino acids on every square, the pellets are melted and the amino acids released. Thus, it is possible to add one building block to all 40,000 peptides on the microchip at the same time. Other methods need several steps to achieve the same result.
Researchers hope that it will one day be possible to produce microchips with several thousand peptides for just a few cents. Using conventional methods, the production of such high quantities of peptides costs several thousand euros. “Our method will facilitate research projects that have previously been too expensive,” explains Ralf Bischoff.
Potential applications for this method include medical diagnostics. The peptide chips are capable of detecting antibodies in a patient’s blood that help to determine the disease. The microchips can also be applied to selectively search for peptides that could be used in cancer treatment or may be potential candidates for vaccines against infections.
Literature: Mario Beyer, Alexander Nesterov, Ines Block, Kai König, Thomas Felgenhauer, Simon Fernandez, Klaus Leibe, Gloria Torralba, Michael Hausmann, Ulrich Trunk, Volker Lindenstruth, Ralf Bischoff, Volker Stadler, Frank Breitling: Combinatorial Synthesis of Peptide Arrays onto a Microchip. Science 318 (5858), p. 1888. DOI: 10.1126/science.1149751
Source: German Cancer Research Centre in the Helmholtz Association - 7.1.2008