Integrated chemiluminescence-based lab-on-chip for detection of life markers in extraterrestrial environments.

The detection of life markers is a high priority task in the exploration of the Solar System. Biochips performing in-situ multiplex immunoassays are a very promising approach alternative to gas chromatography coupled with mass spectrometry. As part of the PLEIADES project, we present the development of a chemiluminescence-based, highly integrated analytical platform for the detection of biomarkers outside of the Earth. The PLEIADES device goes beyond the current lab-on-chip approaches that still require bulky external instrumentation for their operation. It exploits an autonomous capillary force-driven microfluidic network, an array of thin-film hydrogenated amorphous silicon photosensors, and chemiluminescence bioassays to provide highly sensitive analyte detection in a very simple and compact configuration. Adenosine triphosphate was selected as the target life marker. Three bioassay formats have been developed, namely (a) a bioluminescence assay exploiting a luciferase mutant with enhanced thermal and pH stability and (b and c) binding assays exploiting antibodies or functional nucleic acids (aptamers) as biospecific recognition elements and peroxidase or DNAzymes as chemiluminescence reporters. Preliminary results, showing limits of detection in the nanomolar range, confirm the validity of the proposed approach.