Team:BIOTEC Dresden

Detection of cell surface cancer markers is a key diagnostic step during cancer therapy as it allows the efficiency of a therapy to be determined. Current antibody-based flow cytometric detection methods are the gold standard; however, they are expensive and may not be adequately sensitive when the marker of interest is expressed in low quantities. For our 2010 iGEM project, we hope to develop SensorBricks as a reliable and modular system for antigen recognition, signal amplification and quantification. Initial steps of SensorBricks will focus on the detection of CD33, a key marker of leukemia cells.

There are three major components in SensorBricks: (i) monoclonal antibodies that bind to an antigen of interest, (ii) a LuxI-Protein A fusion construct which non-specifically binds antibodies and produces the autoinducer N-Acyl homoserine lactone (AHL), and (iii) a Escherichia coli based biosensor which in the presence of AHL strongly amplifies the production of green fluorescence protein (GFP). By coupling signal detection to a genetic circuit, we will be able to amplify the signal in a quantifiable manner, allowing the identification of cancer markers expressed in minute quantities. The presence of CD33+ cells in the collected blood of a patient will trigger the production of AHL, which in turn, activates the production of GFP in our E. coli biosensor. As such, we will be able to correlate the concentration of CD33 as a function of GFP fluorescence.

The modularity of SensorBricks is a key feature as it allows the same system and protocols to be used in combination with any antibody of choice to detect any antigen of interest.