Team:Freiburg/Project/Overview
Project overview: The DiaCHIP
The DiaCHIP is an innovative tool to simultaneously differentially detect antibodies present in blood sera that correspond to infectious diseases. It may greatly simplify broad band screenings, detection of autoimmune diseases and the determination of vaccination status. Essential for our project idea is the combination of on-demand protein synthesis directly in the diagnostic device, that is using a novel and label-free detection system, so simple that it can easily be rebuild and utilized by future iGEM teams.
Preparing the DiaCHIP
As the DiaCHIP relies on antibody-antigen interactions, the antigens first have to be synthesized and immobilized inside the device. Given that the whole device is a microfluidic system, it was most convenient to do this directly in the flow-chamber, where detection will finally take place. The flow-chamber consists of two glass surfaces separated by a gap that can be flushed with liquids. On the one surface DNA molecules, which code for the respective antigens. By flushing a cell-free expression mix into the chamber, the respective antigens are transcribed and translated on-demand. Proteins then diffuse until reaching the second surface that specifically captures the proteins encoded by the immobilized DNA. After several washing steps to remove remaining expression-mix the flow-chamber is coated with the immobilized antigens and ready for detection.
Measuring
With the iRIf (Abkürzung) system it is possible to record small changes in layer thickness. The binding of an antibody, present in the blood serum flushed through the chamber, to the according antigen increases the local thickness of the protein surface so that interaction events can be measured label-free and in real-time via the change of the optical properties at this spot.
But we didn't stop thinking about the device: We detected antibodies in our own blood!
