DNA chips are widespread as a method to analyze and identify gene sequences on a given piece of DNA. Transferring the technology to protein analysis has been difficult because the unique 3D shape of the protein molecules can be made inaccessible once they are attached to a chip. German researchers from Fraunhofer Institute for Applied Polymer Research IAP seem to have conquered the challenge and created a special gel that may become the primary component in protein chips.
“We have developed a gel – a network of organic molecules – that we can apply to the surface of the biochip,” says Dr. Andreas Holländer, group manager at the IAP. “This gel layer is only about 100 to 500 nano-meters thick and consists mainly of water. We thus make the protein believe that it is in a solution, even though it is chemically connected to the network. It feels as if it is in its natural environment and continues to function even though it is on a biochip.” Other research groups are working on similar hydrogels. The key feature of the new production technique is that it can be applied in industry, and the gel layers can be manufactured cheaply on a large scale. Usually there are two ways of producing such networks. In the first, complete polymers are chemically bound to the surface. In the second, the polymer molecules are constructed unit by unit on the surface. “Our technique is a mixture of the two known methods. We use larger molecular building blocks to build up the network on the surface,” explains Falko Pippig, who is doing his doctorate on this subject at the IAP.
As the hydrogel layers are very thin, substances added from the outside very quickly reach the protein which is in and on this layer. For example, physicians can put blood or urine on the chip and diagnose illnesses. The research scientists have already developed the process fundamentals. Protein biochips could therefore become everyday items of equipment in medical laboratories – the possible applications far exceed those of DNA chips.
Fraunhofer-Gesellschaft press release: Proteins in gel
Image: View into a spectrometer which the research scientists use to analyze the gel layers. Polymer carriers with the gel layers can be seen in the middle.
